Briggs and Stratton Slow Cranking
#1
06-08-12, 10:21 AM
Briggs and Stratton Slow Cranking
I have a Montgomery Ward riding lawn tractor with Briggs engine 12.5 Hp engine model 289707-0154-01. The engine cranks very slowly and stops when it reaches the compression stroke. I thought it might be the battery because it was about 4 years old so I replaced it. No different after replacing the battery. I read that the cam lobe which provides compression release wears prematurely on the briggs motor with the overhead valves and causes this problem. My problem is that my engine is not an OHV engine. I have checked valve clearances and both exhaust and intake appear to be withing spec; .005 on the intake and .007-.008 on the exhaust. Is there a compression feature on the cam lobe of this engine as well? If so, does this mean that the cam needs to be replaced?
I suspect also that the starter may be bad. Voltage at the battery is 12.56 V. Voltage on the outlet side of the solenoid when key is in start position is the same. When I check valtage at the starter lug it drops to 6.8V when the key is in start position. If I disconnect the cable at the starter, I get 12.56V at the starter when key is at start position. Does the voltage drop at the starter indicate a bad starter or is the starter drawing too much current due to compression build-up?
Pmart60
I suspect also that the starter may be bad. Voltage at the battery is 12.56 V. Voltage on the outlet side of the solenoid when key is in start position is the same. When I check valtage at the starter lug it drops to 6.8V when the key is in start position. If I disconnect the cable at the starter, I get 12.56V at the starter when key is at start position. Does the voltage drop at the starter indicate a bad starter or is the starter drawing too much current due to compression build-up?
Pmart60
#3
06-08-12, 06:01 PM
New battery does not always mean good battery. I would have it load tested first. Then check and see if the cable from the solenoid to the starter gets hot when you try to start. If it stays cool, then replace the starter. If the cable gets hot, replace it.
#4
06-08-12, 07:15 PM
Forum Topic Moderator
Does the engine crank fast with the spark plug out? Is there oil on the spark plug? Is there a gassy smell to the engine oil?
#5
06-09-12, 05:53 AM
briggs & stratton cranks slowly
yes cheese the engine cranks fine with the spark plug out. I thought I had it diagnosed as hydraulic lock because gas was getting into the crankcase. I disassembled the carb and found the viton piece on the needle was indeed damaged. I replaced needle and seat and thought I had my problem solved. Apparently that was only one of my problems. It is still not cranking over fast enough to start. Does this engine have a compression release built into the cam or is that only on the OHV engines? I know that on the OHV engines the valves are adjustable to compensate for cam wear, but the valves on this engine are not adjustable and the clearances seem seem to be in spec.
Pmart
Pmart
#6
06-09-12, 05:56 AM
Briggs and Stratton Slow Cranking
I suspected the starter due to the voltage drop at the starter lug and I ordered a new starter. It should be here within a couple of days. I will post the results to let you know if this fixed the problem.
#7
06-09-12, 10:09 PM
that voltage drop might be due to a bad ground. I just had a slow cranking one on a toro. Problem was the ground cable connection at the chassis. I had an L-head that would only crank slow and stop and it was due to too much intake valve clearance. The release is built into the intake cam. I had to replace the valve to get back to the lower clearance.
#8
06-09-12, 10:58 PM
Forum Topic Moderator
Weird, usually in L head engines, the valve clearances decrease, not increase like in OHV engines.
#9
06-10-12, 03:46 PM
Weird, usually in L head engines, the valve clearances decrease, not increase like in OHV engines.
I was surprised because I had not done any thing with the valves, just put rings in it and lapped the valves and lapping would decrease rather than increase the clearance.
I was surprised because I had not done any thing with the valves, just put rings in it and lapped the valves and lapping would decrease rather than increase the clearance.
#12
06-19-12, 03:40 AM
I have the exact same problem
Hi Guys
i have the exact same problems as above, i have put a battery from my car straight too ground and directly too the positive of the starter as i was unsure of the battery in it had enough power, and it still wont crank fast enough, take the plug out and she spins no probs at all, even if i take the plug most of the way out it still spins but not enough, and the plug would need to be in nice and tight, my mower is Not OHC type B&S either,its 12 hp non OHC Briggs and Stratton motor, there is plenty of spark, so im sure it would fire straight up if we could just get the motor too turn over off the starter, ive had the head off there was a bit of gunk, but no signs of wear or scratches inside block,the bore looked fine, piston was in fairly tight, didnt seem like much play, the valves were both moving fine, i didnt check clearances as im unsure of how too, ive read that these motors dont have the adjustments as the OHV engines do, so im at a loss as too why when the plug is screwed in tight it wont let the starter turn it past compression,,, or barley a few times till it stops, and i dont want too ruin the good starter trying too make it turn over, it seems like the compression is way too high with plug in, any help and onfo will be greatly appreciated,,, Troy
i have the exact same problems as above, i have put a battery from my car straight too ground and directly too the positive of the starter as i was unsure of the battery in it had enough power, and it still wont crank fast enough, take the plug out and she spins no probs at all, even if i take the plug most of the way out it still spins but not enough, and the plug would need to be in nice and tight, my mower is Not OHC type B&S either,its 12 hp non OHC Briggs and Stratton motor, there is plenty of spark, so im sure it would fire straight up if we could just get the motor too turn over off the starter, ive had the head off there was a bit of gunk, but no signs of wear or scratches inside block,the bore looked fine, piston was in fairly tight, didnt seem like much play, the valves were both moving fine, i didnt check clearances as im unsure of how too, ive read that these motors dont have the adjustments as the OHV engines do, so im at a loss as too why when the plug is screwed in tight it wont let the starter turn it past compression,,, or barley a few times till it stops, and i dont want too ruin the good starter trying too make it turn over, it seems like the compression is way too high with plug in, any help and onfo will be greatly appreciated,,, Troy
#14
06-19-12, 06:56 PM
starter seem fine with a lot of power, i just got back from local mower shop and they tell me that All Briggs motors OHV or not have the thing on the cam for decompressing for start up, but i dont know weather he is just after my hard earned $$$ as i said i could take tho motor out if they could rebuild it there answer, we need the mower too test it, i asked why cant i take it back home install then bring for testing, there answer was youd have no warranty then,,,, how can they not give warranty if im only only putting the motor back in......... sem all too suspicious too me..
#15
06-19-12, 09:23 PM
Forum Topic Moderator
No, flathead engines do not have a compression release mechanism on the camshaft. In fact, the more a flathead engine wears, the easier it gets for it to crank. How are you determining the starter is good? Can you turn the engine easily by hand? Try taking the belts off the engine pulley and see if it will crank more easily.
#16
06-19-12, 09:32 PM
Hi Cheese
i was pretty much 100% they didnt have a release mech for the cam, but the guy in the mower shop told me, ive since taken off the valve inspection plate and as i and you all told me and expected there is no adjuster,
the engine turns fine by hand i can feel when it reaches the point of comp then off again, my determination of the starter is good, is only since i take spark plug out it cranks fine and fast,even with the plug in lets say 1/4 too 1/2 way screwed in it will still spin ok, but screwed right in,, it just seems too have way too much comp for it too start it, i even disconnected it all together and free spun it, it seems fine no funny noises or anything, i even wnet as far as too jam a screw driver under it in the mower whilst the plug was out and tried putting a little force too load it up,, and it kept spinning no probs, i know it is not the battery because i used my oddesy battery from my supergharged 351, and put the positive straight too the battery and still not enough power too crank it, the guy in the shop told me that All briggs motors have them, and with these motors its on the inside,, whta ever he means by that, just helps add too my confusion. lol,,, hope we can get it sorted soon... thanks Troy
i was pretty much 100% they didnt have a release mech for the cam, but the guy in the mower shop told me, ive since taken off the valve inspection plate and as i and you all told me and expected there is no adjuster,
the engine turns fine by hand i can feel when it reaches the point of comp then off again, my determination of the starter is good, is only since i take spark plug out it cranks fine and fast,even with the plug in lets say 1/4 too 1/2 way screwed in it will still spin ok, but screwed right in,, it just seems too have way too much comp for it too start it, i even disconnected it all together and free spun it, it seems fine no funny noises or anything, i even wnet as far as too jam a screw driver under it in the mower whilst the plug was out and tried putting a little force too load it up,, and it kept spinning no probs, i know it is not the battery because i used my oddesy battery from my supergharged 351, and put the positive straight too the battery and still not enough power too crank it, the guy in the shop told me that All briggs motors have them, and with these motors its on the inside,, whta ever he means by that, just helps add too my confusion. lol,,, hope we can get it sorted soon... thanks Troy
#17
06-20-12, 09:46 AM
Forum Topic Moderator
There is a compression release on the cam grind. It's the way the camshaft is ground when they make it. I don't think I ever saw one that was worn to the point that it wouldn't crank. I doubt it is the problem, but you never know. How did this problem start? Did the engine slowly get harder to start? Did it happen all of a sudden? Do you have a buddy with a single cylinder briggs that might let you try his starter just to eliminate it, or put your starter on his engine?
Last edited by cheese; 06-20-12 at 08:25 PM.
#18
06-20-12, 03:14 PM
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cheese
There is a compression release on the cam grind. It's the way the camshaft is ground when they make it. I don't think I ever saw one that was worn to the point that it wouldn't crank. I doubt it is the problem
There is a compression release on the cam grind. It's the way the camshaft is ground when they make it. I don't think I ever saw one that was worn to the point that it wouldn't crank. I doubt it is the problem
Just as I explained Troy, You can tear the engine apart if you like, But it would be a shame to find the starter was the issue after re-assembly.
I've read many many many threads over the years (I post on four other boards) where "shops/dealer's" have given WRONG advice, Makes me wonder how they stay in business......
Good Luck
#19
06-22-12, 01:13 AM
Gday Cheese
i have another 18 hp V Twin b/s motor, but the mounting is different, tho it looks like i will be able too swap the top mounts over by Unscrewing the 2 main screws up through the starter holding it together and changing the different tops over, as they look identical apart from the mounting points(is this possible? guess ill let you know tomorrow, but at a glance it sure looks like it can be done) and check too see if it is the starter by cranking them both if it works ill then just leave it, i am going too try this 1st b4 i go too the effort of pulling it apart, with your Question on how long prob has been there, i couldnt tell you as i just picked it up from a friend who was going too render it useless, i told him id have a look at it for him before he went and bought a brand new 1 and he couldnt really tell me as i just rang and asked him. im fairly sure i can get another stater too try
31YTech tho on a different note i have a 351 cleveland 671 supercharged in my little
MK III Cortina, and am kind of familiar with weak starters, but by no means do i have the same level of experience as you guys helping on this post with these little engines, i was just letting you know what the guy up the road told me, and i assumed he was only after my money and not willing too help like you guys, i appreciate all your advice and will try it before i go too the effort of pulling it apart
i have another 18 hp V Twin b/s motor, but the mounting is different, tho it looks like i will be able too swap the top mounts over by Unscrewing the 2 main screws up through the starter holding it together and changing the different tops over, as they look identical apart from the mounting points(is this possible? guess ill let you know tomorrow, but at a glance it sure looks like it can be done) and check too see if it is the starter by cranking them both if it works ill then just leave it, i am going too try this 1st b4 i go too the effort of pulling it apart, with your Question on how long prob has been there, i couldnt tell you as i just picked it up from a friend who was going too render it useless, i told him id have a look at it for him before he went and bought a brand new 1 and he couldnt really tell me as i just rang and asked him. im fairly sure i can get another stater too try
31YTech tho on a different note i have a 351 cleveland 671 supercharged in my little
MK III Cortina, and am kind of familiar with weak starters, but by no means do i have the same level of experience as you guys helping on this post with these little engines, i was just letting you know what the guy up the road told me, and i assumed he was only after my money and not willing too help like you guys, i appreciate all your advice and will try it before i go too the effort of pulling it apart
#20
06-22-12, 01:36 AM
also i forgot too mention, i looked on youtube and seen this guy starting his 12hp ride on with a cordless drill, it did it no probs 1st was his 8hp then he started his 12hp im sure they were, so i thought ill go 1 better and simply tried my rattle gun for removing the wheel nuts off my vehicles, it didnt work, so then i thought it needs more power, got a nice square nut too fit into my 23mm socket put that into a drill, placed it on top of the fly wheel nut and then the 1st drill i got was my HILTI Hammer/Drill gave it a hit on the trigger once it got round too point of compression it slpiied in chuck, tightened it unsusally tight then hit trigger again, it broke the top of the nut off, next plan was too find a high tensile nut too fit in socket, that done, i pulled the bigger 1500w AEG Hammer/Drill out, gave that baby a pull on the trigger and point of compression, the drill clutch cut in, and both these drills have much much more power and torque than any 18v cordless drill the other guy was using on you tube, so hopefully with this info it eliminates the weak starter and you guys may be able too point me in right direction,,,, knowing my luck i will be the 1st n last guy you hear of with a worn compression release grind on the cam, that would be just the type of weird thing that haunts me from time too time lol
thanks again Troy........
thanks again Troy........
#21
06-22-12, 09:04 AM
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Troy_A
so hopefully with this info it eliminates the weak starter
so hopefully with this info it eliminates the weak starter
Do you think you could take the starter off your huffer engine weld a socket to the bendix and shove it on the harmonic balancer bolt and start it up ?
Power and torque means nothing unless you have the gear reduction to go with it, Meaning the small starter gear spinning the larger flywheel gear. Same applies with your huffer engine.
One last thing, Using a rattle gun or hammer drill or any drill for that matter on a flywheel bolt/nut to try cranking can cause a few issues. Stripped crank threads, The whole top of the crank can be snapped off or the flywheel cracked from over tightening......
#22
06-22-12, 10:13 AM
Forum Topic Moderator
Sorry Troy but it doesn't, About the only way a cordless drill put right on a crankshaft will spin a engine over is if it's worn to the point there's just enough compression to run (40-50lbs)
#23
06-22-12, 05:09 PM
Hi Guys
im trying the starter off the 18hp b/s motor later today, however i have them both off and placed them into a vice seperately, i hit the 12v power too them put a shifter on the starter on the bottom hit it with some power, and they both seem too have the exact same amount or atleast it feels like it through my arm.... a big call i know as my dosent have a torque meter connected too it... Drill Starting a 12HP Engine - YouTube
this is the link for the fellow using the drill, i made a mistake he had 2 drills and 1 12hp mower, you can clearly see it has plenty of compression on the 12 hp motor how the 1st drill finds it hard too start, as mentioned the 2 drills i used mave much much more power and torque than a cheapo Ryobi 18v cordless, i just tried my 20v cordless DeWalt drill even tho i knew it wouldnt turn it which it didnt , the drill idea, was just too throw it out there as a "possible" way of it being inside the motor and not the starter, i would have thought my Big Assed drills would of atleast turned it over, but i have been proved wrong many times in the past and im not disregarding what you guys say, i am trying all options,(besides my fav Quote is your not silly if you dont know something, ur silly if you dont listen and try the advice of others with the knowledge your after, too not know somthing dont make you dumb, too not listen and learn from those who want too teach you makes you dumb.... so ill be listing too my own quote and try all your advice.... many many thanks) the link i had seen it on you tube, ill try find them and put it on too have a look for a laugh, if it did work i would never use that method for normal start ups, it was just a quick way try eliminate the starter, which im 99% certan its ok, but with 1% doubt i must as i have take it off and check against another starter, then will i only be 100% in the analysis of it being the starter or not.
im trying the starter off the 18hp b/s motor later today, however i have them both off and placed them into a vice seperately, i hit the 12v power too them put a shifter on the starter on the bottom hit it with some power, and they both seem too have the exact same amount or atleast it feels like it through my arm.... a big call i know as my dosent have a torque meter connected too it... Drill Starting a 12HP Engine - YouTube
this is the link for the fellow using the drill, i made a mistake he had 2 drills and 1 12hp mower, you can clearly see it has plenty of compression on the 12 hp motor how the 1st drill finds it hard too start, as mentioned the 2 drills i used mave much much more power and torque than a cheapo Ryobi 18v cordless, i just tried my 20v cordless DeWalt drill even tho i knew it wouldnt turn it which it didnt , the drill idea, was just too throw it out there as a "possible" way of it being inside the motor and not the starter, i would have thought my Big Assed drills would of atleast turned it over, but i have been proved wrong many times in the past and im not disregarding what you guys say, i am trying all options,(besides my fav Quote is your not silly if you dont know something, ur silly if you dont listen and try the advice of others with the knowledge your after, too not know somthing dont make you dumb, too not listen and learn from those who want too teach you makes you dumb.... so ill be listing too my own quote and try all your advice.... many many thanks) the link i had seen it on you tube, ill try find them and put it on too have a look for a laugh, if it did work i would never use that method for normal start ups, it was just a quick way try eliminate the starter, which im 99% certan its ok, but with 1% doubt i must as i have take it off and check against another starter, then will i only be 100% in the analysis of it being the starter or not.
#24
06-22-12, 08:36 PM
Forum Topic Moderator
That's a different engine... OHV with compression release, and old as the hills, probably not the best compression, and the drill still had a hard time getting it over the comp stroke. I'm not saying it can't be done, but it isn't any kind of accurate indicator, and a hammer drill or impact will definitely not do it as well as a regular drill.
#25
06-23-12, 06:21 AM
well i didnt get time too test or change over the starters and work it out today, way too busy, but ive had some luck and got my hands on a working b/s 12hp motor that is running, im picking it up tomorrow, so soon as i get my hands on that little baby ill be testing the starter from that, as we know that it is fine and starting an identical type of engine, it was a bargin so i could not let it go, i got it for a mere $80 complete, they want that for a 2nd hand starter, so i cant go wrong with all the spares, and then i can find out if it is the starter or not, then use the new motor as a guide for measurements and valve measurements and so on, before the big job of pulling it down if it needs too be and or changing them over, tho if the 1 in the mower now needs pulling down ill be putting the $80 engine till the rebuild has been done,,,,, ill ket you guys know tomorrow afternoon how i went with it all, and may need too pick your brains a little more,,,, many thanks Troy
#26
06-23-12, 10:08 PM
Well it looks like ill have too 
pull it down and inspect what is the problem, i got my hands on the $85 engine, put 12v too it,she cranked over no worries, so i then took the original starter from the motor which it wouldnt turn over bolted it too new $85 motor, it spun it over a bit better than its original 1, even know i knew it wouldnt turn the original motor over, i bolted the $85 motors starter too the mower and it just did the same thing, hit the compression stroke and wouldnt turn it over, do you guys have any other advice or tips too try or other areas too look at, before i have too pull it down, thanks again for your help...
upside of pulling it down, atleast ill know what im doing in the future, and we may just do a little port work on the inlet and exhaust whilst she is apart if it goes that way....
pull it down and inspect what is the problem, i got my hands on the $85 engine, put 12v too it,she cranked over no worries, so i then took the original starter from the motor which it wouldnt turn over bolted it too new $85 motor, it spun it over a bit better than its original 1, even know i knew it wouldnt turn the original motor over, i bolted the $85 motors starter too the mower and it just did the same thing, hit the compression stroke and wouldnt turn it over, do you guys have any other advice or tips too try or other areas too look at, before i have too pull it down, thanks again for your help...
upside of pulling it down, atleast ill know what im doing in the future, and we may just do a little port work on the inlet and exhaust whilst she is apart if it goes that way....
#27
06-23-12, 10:49 PM
Forum Topic Moderator
Nope, if nothing is dragging the pulleys, flywheel, there is no gas or oil in the cylinder, and the starter, connections, and battery are good, I don't have any other suggestions.
#28
06-24-12, 04:42 AM
thanks for all the advice, thought id just let you guys know, the little person inside me who hates too be wrong thought he would try too use the same drills he used as a ""TRIAL"" too eliminate the starter(i didnt bother with the rattle gun),if you know your battery and other things are fine as it was in my case, its easy too turn the new motor over with all 3 drills i mentioned in the above posts, 2 were Hammer drill / drill, i think that it could be used as both drill and hammer drill may have been over looked,and the 20V De Walt cordless worked well,(tho nt a good idea for every time start ups it as mentioned could cause unwanted problems due too over tightening bolts and so on),i knew or was 99% sure it was the motor not the starter. i know the other motor is OHV but its decompression is obviously working fine,allowing the 2 cordless drills he used too start that 12hp motor and my MTD is a few years old as well (or an old girl), i do understand power and torque and reduction gearing, but i also know that the large drills i was using had more power and torque than the 12v starter would have or atleast equal too it,and not too mention that there are many 12hp motors with pull starts, so any Good Powerful Drill will obviously turn a little engine over, not necessarily start it tho, and the idea of the drill was just too see if the motor would turn over (as we now know they do), if it would then it would certinally point too a weak starter motor, some times its better too step out of the box and trial new things it can give pleasant results, ill be pulling the other motor down too see if it is the lobe on the cam worn or something different, i will keep you posted too let you know the out come,,, again many thanks for your comments and help, greatly appreciated... Troy
PS
Here is a picture of my Beast i have in the shed, she has got just off a lazy 850HP at the Fly Wheel, and a hell of a lot of fun too drive, its only 1275kgs with me sitting in it ready too race.......... Thanks again Guys..... Top Stuff!!!
PS
Here is a picture of my Beast i have in the shed, she has got just off a lazy 850HP at the Fly Wheel, and a hell of a lot of fun too drive, its only 1275kgs with me sitting in it ready too race.......... Thanks again Guys..... Top Stuff!!!
#29
06-24-12, 06:53 AM
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Well Tony,
This is very surprising, I'll have to put this one down as the first. If or when you get the cam out look at the sides of the lobe, There's no specs on how high/wide its supposed to be so it's hard to tell without a new or known good one sitting next to it.....
PS,
Thanks for the pic of your toy, Before this was all over with I was going to ask you to post one. I know it's got to be a blast to drive !!!
Here's a pic of my ole truck, A measly 725 hp at FW on the bottle.....
Good Luck
This is very surprising, I'll have to put this one down as the first. If or when you get the cam out look at the sides of the lobe, There's no specs on how high/wide its supposed to be so it's hard to tell without a new or known good one sitting next to it.....
PS,
Thanks for the pic of your toy, Before this was all over with I was going to ask you to post one. I know it's got to be a blast to drive !!!
Here's a pic of my ole truck, A measly 725 hp at FW on the bottle.....
Good Luck
#30
06-24-12, 02:29 PM
did you actually use a volt meter and due any voltage drop readings as per this MTD article.
http://www.google.ca/url?sa=t&rct=j&...I_mQsA&cad=rja
I thought I ha dposted it for you but I guess it was on another forum
http://www.google.ca/url?sa=t&rct=j&...I_mQsA&cad=rja
I thought I ha dposted it for you but I guess it was on another forum
#31
06-24-12, 04:35 PM
Nah i didnt bother with the Volt test, Also i dont see the need too do 1 now, as ive most probably found it too be the motor its self, as i have switched starters over from another 12hp B/S, but ill keep it in mind for next time tho..... and just too keep me going i simply changed the motor over too the 2nd hand $85 bargin i got my self,
i need some tyres on the back of mine like you have on ur Truck, but the bloomim RTA wont allow the size i need,,, or the 671 on top of the motor, but we can easily take that off for rego... lol
i need some tyres on the back of mine like you have on ur Truck, but the bloomim RTA wont allow the size i need,,, or the 671 on top of the motor, but we can easily take that off for rego... lol
#33
06-25-12, 12:52 AM
this is a bit like my tyres,,,,,,,, lol,,, :NO NO NO: goes tho Police officer......
Screams the passenger
is the Misses if i race at the lights,, or mash the Go Fast Pedal,,,,,,,,lol..but back too B/S motors, ive got the new 1 all bolted in powered up and fuel in her, but it just dint want too fire,plenty of spark,,but the carb may need a clean out, not sure how long its been sitting around, tho i did only get too spend no more that 15mins playing... ill have more time tomorrow, so ill get back into it then...........
#34
06-25-12, 09:53 PM
Ok Guys 
im in need of some more advice, i worked out why the new motor was not firing, it was because the carby was full of water
, i cleaned it all out of the bowl and in tje hole up the center from the float, so the fuel goes too the top of carby, i hop you understand my jibber there
...
the problem now seems too be that it is not drawing the fuel up into the cylinder too fire the engine, but if i do something that might go >>
, like i did, i got an areosol can lid you know how they have a tiny hole in them, well i filled the lid up with fuel held it over the carby and let it drip in, hit the starter she fires up right away, and will keep running whilst im letting the fuel drip in from the lid, once the lid is empty the motor die's from no fuel, i know the fuel from the tank ig getting too the carb no problem with blockage there, its definately in the carb, the bottom screw in the fuel bowl, with the needle type end, how many screws does it need to be unscrewed from tight, i assume this is a mixture or something............
Like always any help is greatly appreciated
im in need of some more advice, i worked out why the new motor was not firing, it was because the carby was full of water
, i cleaned it all out of the bowl and in tje hole up the center from the float, so the fuel goes too the top of carby, i hop you understand my jibber there
... the problem now seems too be that it is not drawing the fuel up into the cylinder too fire the engine, but if i do something that might go >>
, like i did, i got an areosol can lid you know how they have a tiny hole in them, well i filled the lid up with fuel held it over the carby and let it drip in, hit the starter she fires up right away, and will keep running whilst im letting the fuel drip in from the lid, once the lid is empty the motor die's from no fuel, i know the fuel from the tank ig getting too the carb no problem with blockage there, its definately in the carb, the bottom screw in the fuel bowl, with the needle type end, how many screws does it need to be unscrewed from tight, i assume this is a mixture or something............ Like always any help is greatly appreciated
#35
06-26-12, 12:14 AM
Forum Topic Moderator
That's the high speed mixture screw. There is no preset setting for it. You adjust it for the best high speed performance while the engine is running. I would remove the carb, take the center jet out, take the jet out from the top of the carb, and clean it all. Something is still clogged.
#36
06-26-12, 08:58 AM
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cheese
There is no preset setting for it.
There is no preset setting for it.
Tony,
What Mr Cheese means by this is there's no factory setting, If you remove this lower adjuster for cleaning open it from closed position 2 turns. This will get the engine running so it can be fine tuned as mentioned, You also have the low/idle mixture adjuster on top of the carb. Remove and clean this passageway then open it 1.5 turns, Fine tune this one at idle speed.......
#37
06-27-12, 06:08 AM
ok thanks guys, i pulled the all down today gave it a real good clean out, and what do you know............ it fired up and ran, but i shut it down a few minutes later as i had other things too get done, but atleast its going, ill give it a bit of a tune when i get some time too look at it again....... many thanks for all your help...... now too pull the other 1 down for a look... thanks Troy........
#38
09-10-12, 09:24 PM
Slow cranking etc.
[SIZE=3][/SIZE][SIZE=3]I have read almost all of this thread and have had the exactsame starting problems. I have even been in touch w/ the B&S help group andtried everything to get my 12.5 hp engine to start as it originally did. Thefirst time their were started issues was about 5 years ago but I was alwaysable to start the engine after a couple of tries. The best results I have comeup with are using jumper cables connected to a spare car battery. I connecteddirectly the ground to the frame and the + clamp to the starter post. Theengine cranks like a champ but I still need to give the carb a shot of startingfluid to get things going. I have rebuilt the carb (replaced the float/needlegaskets etc.)totally de-greased, boiled and solvent cleaned all the passagesbut still have problems starting the engine in the normal way. I have foundthat hand cranking the flywheel so that the engine is not having to crankagainst the compression cycle helps. The B&S help group states that theythink the problem is with the "compression relief mechanism". I cannotfind any mention of this function in any of the B&S literature. Oneinteresting note is that on this engine, two different cam P/N's are called outin the parts lists. IS their a cam with a comp rel "bump" and onew/o? I cannot think of any other answer as to what is going on with theoperation of this engine!! What else could explain the problem???ThomasP[/SIZE]
#40
09-11-12, 02:31 PM
Cheese,
It is a flathead. I just cut the lawn this afternoon and had the same problems as previously noted. I did forget to note in my original blurb that he compression is very strong still! I get great starter power with the jumper method. The only thing I hate to have to jump-start the engine all the time. I still had to use starting fluid to start the engine today.
It is a flathead. I just cut the lawn this afternoon and had the same problems as previously noted. I did forget to note in my original blurb that he compression is very strong still! I get great starter power with the jumper method. The only thing I hate to have to jump-start the engine all the time. I still had to use starting fluid to start the engine today.
