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Lawn mower seized


sjharwick's Avatar
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07-19-07, 10:07 PM   #1  
Lawn mower seized

My 20 hp Murray has always had good oil levels, so I got lax in checking it. while mowing it died, similar to cutting very high grass and bogging down. I tried to restart but the starter would not turn it over.After topping off the oil level I took off the screen and tryed to turn it with a cresent wrench on the top nut. I took out the spark plugs and spayed penatrating oil and got it to unseize. but the starter still only turned it half the way and would stop, I then would get it over the tight spot with my ratchet and the stater would turn it thru the easy part. doing this for awhile it seemed to be getting easier, and then I burn up the starter silenode. I took the heads off and the piston cylenders seem smooth and all four valves go in and out. I now can turn it with just my hands and it seems even thru-out the entire cycle. I am thinking about putting it back togeather and seeing if the starter will now turn it over, but because I have not really done anything to it (other than spraying oil into the cylinder and turning the pistons in and out), I fear it will not turn over as before when the heads were on and it could build up pressure inside, (I'm thinking maybe it has too much pressure for the stater moter to overcome? and maybe the valves need adjusted???)
I was hoping that only the piston rings had gotten stuck and released when I put the penatrating oil into the piston cylender. I also changed the oil and felt for grit in the old oil and could not find any

 
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07-20-07, 02:08 AM   #2  
You've always kept the oil level proper but have you changed the oil regularly (at least annually)? When you did have to top it off this time, how much did you have to add? Generally, the first area of seizure will be the connecting rod(s) to the crankshaft and spraying lubricant down the spark plug hole would provide no benefit in such cases. Are you sure you don't simply have a weak battery or maybe a weak starter motor? Have you tested the battery strength to know its condition? Or, perhaps even, you have corroded battery cables/ends and not getting proper electrical current flow to the battery.

 
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07-20-07, 12:49 PM   #3  
I changed the oil in the winters, this is the seventh season I've had it.
My dad suggested a weak starter as well, but I could not turn it with a wrench until after I sprayed into the sparkplug holes, and then It was a hard turn and got easier as I turned and sprayed more oil, Marvel Mistery, 10w40, ect. I guess I'll put the head covers back on and try it again.

The dip stick showed no oil, I think I added one quart to bring it to normal

I jumped the starter off my truck, thinking the added power might turn it over


Last edited by sjharwick; 07-20-07 at 12:55 PM. Reason: add more info
 
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07-22-07, 06:08 PM   #4  
If you had to add 2 pints of oil to an engine that holds only 3 pints i'd say you have a tight engine. And depending on how long you have run it with such a low oil level you may have toasted most internal engine components including the three crank bearings, connecting rod bearings, piston and cylinder. Pulling the cylinder head off would give you a good initial diagnosis and would be my first step.

 
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07-23-07, 07:10 PM   #5  
It started.... Thanks everyone for your help. I've only ran it for half a minute thus far and at half idle at that. Tomarrow I'll see if it's up to mowing my two acres of now high grass. Dad suggested I but about a tea spoon of moter oil in the gas tank, and some STP oil in the engine oil.

 
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07-24-07, 07:25 AM   #6  
Is this an opposed twin briggs?
I have had a few of these stick from lack of oil. If they free up they seem to be ok as long as the oil is not let to get low again. It needs to be checked religiously each time the mower is used. If it doesnt smoke and use oil excessively, you will prolly be aight.
I don't know about any engine oil in the gas, I don't think it will be any help for the engine sticking or any thing else for that matter. Just use a good 30W oil and keep the level at the full mark. Anything added to the fuel will likely only effect the valves any way. Personally I would not use any oil additive either unless you have a pressurized oil system (oil filter)

 
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07-25-07, 06:33 PM   #7  
It is a Murray Select wideBody LT, Briggs & Stratton Twin 20HP Diamond I/C
Model 460707, type 2278 E1, Code 9910205A

I had it running the other day by jumping the starter off directly, so I decided to buy a new solenode (I over heated the old one trying to turn over the resistant engine), now It won't start again. I'm not sure I got the wiring right on the solenode, I had it disconnected too long and should have drawn myself a picture. I put the big red wire from the battery and the small red wire from the ignition on the top post farthest away from the flat post on the bottom.
I have just the big red starter wire on the other top post, above the flat post. I have the small black wire from the ignition on the ground nut holding the solenode on the frame. and the small orange wire on the flat post (I know it's right, It has the only flat slot).
I have no spark on the spark plug when I hold my srewdriver in the spark plug wire socket and hold it next to the spark plug nub.

 
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07-25-07, 10:08 PM   #8  
Unplug the kill wire from the coil and check for spark again. If none, the coil is bad. If there is spark, the kill wire is grounded somewhere.


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07-29-07, 12:54 PM   #9  
Well Ignition coil was bad, bottom had burst out exposing wound coil wires, I replaced with new ($50). Lawn mower started right up. and I mowed for about 30 min. It was a little smokey, then it started knocking and stalled.
I'm now out ($20) for the solenode, and $50 for the ignition coil (unless the parts place will take them back, but I dought it (no returns on electrical). Of course the wife wanted me to get a new one from the start. (about 1200-1500 for the same type). I've found anouther engine for ($150)
(talk about beating a dead horse)...wish me luck.
Is it just a fluke the coil went out during all this, can turning over an engine without the sparkplug wires attached burn up the coil? (no where for the charge to go?)

 
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07-29-07, 09:16 PM   #10  
The bottom of the coil bursting out is indicative of voltage being applied to the kill wire. If the battery was ever connected backwards, or if someone connected a hot wire to the black kill wire, it would have done this. Turning it over with no plugs won't do it.

I didn't figure the engine would run long after locking up. They almost never do. Maybe you'll come out better with the used engine?


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07-30-07, 03:40 PM   #11  
what do I need to make sure of before buying another motor, I had a 20 hp will an 18 hp work ok?
Does the type need to be the same?

 
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07-30-07, 05:14 PM   #12  
An 18 should work fine, provided the engine will fit. The engine numbers don't have to be the same. I suggest using "like" engines though. If you have a "V" twin briggs intek engine, then I suggest using another "V" twin intek engine. If it's an opposed twin, I'd go with another opposed twin. Then verify that the crankshaft is the same as your old one. If so, the swap should be easy.


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08-06-07, 06:29 PM   #13  
My crankshaft pully does not seem to have a bolt inside it? It has a hollow shaft and possibly a round nub about 2-3 inches inside but I can not get any size socket to fit on to anything. I guess I need to lift the front of the mower up so I can get a better look. the replacement engine I bought had a bolt which I removed but I still need to get a pully puller to get it off.

 
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08-06-07, 09:04 PM   #14  
It's a bolt...you should be able to remove the bolt with a 5/8" socket.


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08-10-07, 07:25 PM   #15  
Thanks Cheese, 5/8 socket fit after I got all the caked on dirt off.
I now have the replacement engine on my mower, but I can not get it to run without intermentant sparys of starter fluid into the carberator. It ran fine on the other mower, although I now remember the seller adjusting or holding something in place under the carb with his fingers while it was running, though I dont remember him holding it the whole time, but I'm not sure now. When I first started it it ran wide open for a few seconds, I was trying to throdel it down, when it seemed to run out of fuel. maybe used up all that there was still in the carb. It would not even try to restart untill I used starter fluid and will run as long as I give it a shot every second or so. I'm thinking of putting my old carb, intake, and all the butterfly spring/adjusters from my seized engine on it, looks like 4 bolts will take off the intire intake with the carb attached, and 3 bolts to take off the adjusting assimally. Any suggestions, thanks

 
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08-10-07, 07:36 PM   #16  
I think you'd be ahead to just swap the carbs like you suggested, although I'd just swap the carb, not the intake.


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08-14-07, 07:03 AM   #17  
After switching out the carburetors, I still had the same problem. almost full choke to run at all and at times very fast, the throttle did not seem to do anything no matter were I put it, It was drinking gas very fast too.
It seems the governor was overriding the throttle. I think I got it fixed now by putting on a longer wire from the governor to the carburetor. now It runs with the choke in (open), the throttle idles fast or slow when I adjust it, and the governor gives it more gas when the grass gets thick, and my grass is very high by now . Thanks to everyone who helped, special thanks to Cheese, by the way I love your quote, and with the help of this site, I think He has.

 
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08-14-07, 10:06 PM   #18  
Good to hear that you've got it going! The part about the longer governor linkage has me concerned a bit though. I guess as long as it isn't over-revving, then it should'nt be hurting anything. It still indicates another problem if it doesn't work properly with the correct linkage. Don't let it overrev though. It won't take much of that.

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08-19-07, 08:08 PM   #19  
mower seems to run badly again. I put the original governor linkage back on and it is running better, the old replacement engine had set outside for a long time, maybe something in the governor was sticking?? It seems to run decent again, I mowed my two acres of high grass with it. But If I stop to get a drink or something it will not restart untill it cools off. what could cause that??
it was getting spark and fuel???

 
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08-20-07, 03:39 AM   #20  
I'm confused, is it running well or poorly now? What could cause the difficult hot re-start? Incorrect start procedure, weak ignition, valve clearance issues or vapor lock with the fuel system.

 
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08-20-07, 04:43 AM   #21  
it runs decent and will mow the grass as long as I want to. but if I turn it off it will not restart for about an hour. then it starts back up easly??

 
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08-20-07, 09:38 PM   #22  
I lean to the coil being the problem here. You verified it does have spark when it's hot? Good strong blue spark?


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08-31-07, 12:50 PM   #23  
I replaced the coil, everything seems great now. It restarts after shutting it off (even when hot), runs stronger, and is not sucking down the gas it was before, and I'm not having to pull the choke or the rig the governor linkage longer than normal just to get it to run. I guess it was just a weak spark?
Thanks for the suggestion.

 
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08-31-07, 08:31 PM   #24  
Good news. Weak spark causes several problems...some are hard to diagnose. Glad to hear you got it straightened out.


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