Scotts 21" push mower

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  #1  
Old 06-27-04, 11:06 AM
Azis
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Scotts 21" push mower

Scotts #'s (LM21SW) Model 907254
Briggs motor is missing part of the cowl so not sure I have all the numbers...
Family YBSXS.1901VE Model#? 274474
The original problem was it would not run without putting fuel in the carb. I removed and cleaned the carb (had to soak in carb cleaner for a spell) and got it runnining. However it is very hard to start. The primer bulb is incorparated in the air filter housing, the plastic ring that fits over the bulb looks like it should snap in to hold a seal. The ears on the ring are a bit, well not their . The bulb also has a hole in the end of it.
The carb has no choke and no throttle When priming I can see some fuel getting pumped to the carb but sounds like a lot of air syphoning with it.

So my ? how important is the sealing of the primer, is it part of the carb circuit or just the starting. Once started the thing is just a monster.
Also the owner said that every since he unboxed it, it has started hard, main problem being when pulling it hits a compresion block and nearly pulls your shoulder out. At first I thought it might be the drive wheel making contact so I pulled the plug and it will pull freely all day long. Is there possibly a slight timing adjustment? I did not see the old plug, (it was replaced before bringing it to me to look at) but I dont see any signs of oil or excess fuel in the cylinder.
 
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  #2  
Old 06-27-04, 08:05 PM
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I couldn't make anything of that model#. Are you sure it has no throttle?? How does it regulate engine speed? The reason you have to put fuel in the carb is obviously because of the condition of the priming circuit. You'll want to have the bulb retainer in place, and the gasket between the filter housing and the carb has to be in good shape. Also the bowl gasket needs to be intact and in good shape for the primer to work like it should.
 
  #3  
Old 06-28-04, 08:34 AM
mormiston
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I believe this is made by John Deere for Scotts the model I have is 6213. It has a B&S 6.5 Intek Edge motor model No - 121602

I find it hard to start, four to five pulls before it goes, usually starts with a burst of power and then flattens out. It typlically will start spluttering half way through the yard. Sometime this is accompanied by white smoke, and after a while it will die completely. Cleaning the plug will get it going for a short while but performance degrades from there.

I have taken the head and the carb off several time for cleaning. Seems to be quite a bit of carbon on the exhaust valve and oil on the plug.

The carb also seems to get a bit dirty.

Currently I have pulled the motor down and checked the rings, piston and barrell all looks OK no scoring.

The carb has been cleaned again, but there appears to be no adjustment screws for mixture or idle.

While I have it apart is there anything anyone can think I should look for in terms of why this engine is so unreliable and hard to start.

Thanks
Matt
 
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Old 06-28-04, 10:04 AM
Azis
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Cheese,
It does have a throttle butterfly, but is not operator controled and only runs at full throttle. I do have this one starting on the first or second good pull(good pull being about all my 130lb frame can throw at it ) that no compresion kick back happens whether supplement fuel is added or not seems to make no difference since cleaning the carb.

Matt,
If you have the piston removed and can find the overhaul/rebuild specs, you can check the ring gap and measure the cylinder bore. Valve guides would be the another place to check for oil fouling. If the ring and bore measure out maybe just a hone job on the cylinder. If you have it torn down that far, a valve job is faily painless and inexpensive.
 
  #5  
Old 07-06-04, 01:53 PM
mormiston
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Hi Guys

I have this mower back together after getting hold of the owners and repair manual. Unfortunately, I have had no luck fixing the start problem, I can't get so much as a kick or a puff out of it. The spark plug is fine, I get could spark, the fuel is primed, with the air cleaner off I can see it sucked into the carb, but I still don't get any ignition.

Any last thoughts before this mower is RIP. Personally I am not fond of carbs I cannot adjust. I have a Craftsman with an adjustable carb and after a clean and tune it runs great.

Thanks
Matt
 
  #6  
Old 07-07-04, 12:49 AM
Azis
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I was at the same point with the one I had, I had soaked the entire carb in the NAPA special juice for 30 mins, reassembled and same luck you have now. I removed again and soaked again for about an hour this time, now it does start but takes 2 or 3 good tugs when cold.
 
  #7  
Old 07-07-04, 01:08 AM
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Have you guys checked valve clearances?
 
  #8  
Old 07-07-04, 06:05 AM
mormiston
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Checked the piston and rings, valve clearance and seating and tappets. No luck
My sense is these are a good engine let down by a poor carb. No adjustment screws make these difficult to deal with.

Looking at the carb closely it appears like the fuel never even enter the throat of the intake chamber. I know the bowl is full but the fuel seems to stop flowing right about there. The spark plug doesn't even have the smell of gas on it.
 
  #9  
Old 07-07-04, 10:24 AM
johntcc1
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I had a similar problem with my sears mower. Same issue with the fuel bowl being full. Turns out a minute piece of debris was blocking the fuel jet. I mean it was smaller than the dot on this page. After cleaning it out, haven't had a problem since.
 
  #10  
Old 07-07-04, 01:48 PM
mormiston
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Thanks. I pulled the carb down as much as possible and degreased it, I then blew it out with compressed, this got some ugly looking muck out of the jet. I'm pretty sure it is clean, it just doesn't make sense any priming the sparkplug with a little fuel, didn't even get a pop.
 
  #11  
Old 07-08-04, 12:53 AM
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Matt, is there any chance the flywheel nut didn't get tightened well enough when you had it apart, and now the flywheel key is sheared? If you don't even get a pop when the cylinder is primed with gas, then you have some other problem.
 
  #12  
Old 07-08-04, 07:45 AM
mormiston
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I don't think so. I can feell the piston reach TDC and compress whatever in the chamber. If I understand this correctlt the crank shaft and ram rod would not move at all if I had sheared the Flywheel key.

It is a strange one.
 
  #13  
Old 07-08-04, 09:23 AM
Azis
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Uhmm no that is not correct...the flywheel key aligns the flywheel with the crankshaft so that the magnet passes the coil at the precise moment needed for the spark plug to ignite the fuel/air mixture in the chamber slightly before at or after top dead center, in other words it is ignition timing. Since the flywheel still spins and passes the coil, it will still produce spark at the plug, however if not aligned (or keyed) it will not spark at the correct time. Alot of the time with a sheared key, the engine will pop or backfire.
How are you testing the spark? I am with Cheese that if you have good spark (tested with the spark plug being used) and you put fuel in the chamber via the plug hole or throat of the carb, and the timing is correct you should get life. I recently had one however that I could produce spark with an inline tester and the plug looked fine, later (after assuming I had good spark but no luck starting) I rechecked spark at the plug. I got none, installed the tester again and had sparky in my tester...removed the coil for ID in buying a replacement, my parts guy was out at the time so I went to reinstall the coil, coils are marked Cyl side, this side out (or similar) when mounted correctly the wires routed a bit different, the coil had been installed upside down. Installed it per the writing and voila. I have also chased a bad plug b4 due to relying on my tester I have since reverted back to my old test method which is to use an old jumper cable, remove the plug install the high tension lead and clamp the cable to the threads of the plug the other end to a good ground on the engine. This allows hands free testing of the ignition and spark plug in use
 
  #14  
Old 07-08-04, 10:33 AM
mormiston
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Wow, thanks. I'm not sure I got all that first time round.

I have a very low tech method for testing the spark plug. I remove the plug from the head and connect it into the lead and rest it against the metal part of the engine. I then pull the cord while watching the plug spark, which it does.

I never took the flywheel off, but what you have mentioned is what the service guy said they replaced last time I took it to the shop, "the key for the fly wheel". I know the fly wheel turns when I pull the cord and that I have spark. Is there a simple way to test that my ignition timing is correct?

I'll have to check and see if the key has sheared.

Thanks in advance.
 
  #15  
Old 07-08-04, 04:27 PM
Azis
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Not a simple way I know of to check exact timing, but since you are not getting even a pop, with the piston at Top Dead Center, the magnet on the flywheel should be at the coil. Some may have marks but none I have seen or know or rather.
You mentioned checking piston, rings, valve clearance and seats??? Yet you did not remove the flywheel? Not that removal of the flywheel is necesarry to check those but how far did you disasemble and how did you check?

Make this test b4 replying....
Put 2 teaspoons of good fuel in the throat of the carb, see if you get life, if not check the key on the flywheel, unfortunatly some keys are hard to inspect by looking down the shaft. However since you are not getting even a pop, your key may be missing or completely spun around.
Let us know plz n gl
 
  #16  
Old 07-08-04, 10:27 PM
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The only way to know for sure is to remove the flywheel nut, washer, and starter cup and look at the key. The flywheel key won't stop anything from turning. It just throws the ignition off if sheared.
 
  #17  
Old 07-09-04, 09:23 AM
Azis
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Uhmmm WOW guess what I found folks.......
http://www.cpsc.gov/cpscpub/prerel/prhtml01/01106.html

Unfortunatley the recall is not for the engine or related, however looks to be a serious saftey issue. I just informed my customers that I know own these, maybe I can get some inside snuff on the engine troubles on these in the proccess.
 

Last edited by Azis; 07-09-04 at 09:41 AM.
  #18  
Old 07-09-04, 10:22 AM
mormiston
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Guys you are champions and legends. The flywheel key was sheared.

Now to answer some questions. I broke the whole mower down to the crank case, beleive it or not the only part I didn't disassemble was the fly wheel because I didn't have a puller and didn't understand the job of the key.

When I finally got it off last night, there had been a good 30 degrees movement, I never would have had a hope in starting it.

I replaced the key steel reassembled and on the second pull it started. Still knocks a little but at least now it goes.

Thanks again for the all the help, I appreciate the community helping me identify the problem.

Matt
 
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Old 07-09-04, 11:06 AM
Azis
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Good deal glad to hear it. Check out the recall also, if your model is included looks like it is a serious matter and safety issue.
 
  #20  
Old 07-10-04, 12:36 AM
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Glad we were able to help! As for being a "legend"...well, as much as I like the idea, that might be a bit much .
 
  #21  
Old 07-12-04, 07:39 AM
mormiston
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Thanks anyway, I appreciate you taking the time out to help me diagnose. Since I have it going again, I am going to get a few replacement parts and get it back to full working order. I hate it as a side bagging mower, but it does a good job as a mulcher.

Azis, I check the mower against the recall it doesn't affect mine. Thanks for sharing.

Matt
 
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