I have 917.387321 craftsman push mower (1998). Tonight I pulled the shroud off, cleaned the engine (wiped it down) of dirt/grease, etc. I put shroud back on, drained and put in new oil and replaced the air filter. Now, when I pull rope, it jerks back out of my hand about half-way out. If I pull rope slow, I can fairly easily pull rope way out, but pulling fast/hard on it and the rope wants to jerk back. If I am at all successful at getting engine started, it sounds like it's not quite running at full power, and occasionally a minor backfire. When I release the brake handle, the engine stops NOW, rather than the usual 1 or 2 seconds it normally takes. If I remove the shroud, and put my hand on the flywheel (which has the magnet on one side and a balance weight embedding across from it), I can easily rotate it around...no resistance. I don't understand why all the sudden this is occurring. I had started the engine just minutes prior to warm the engine before changing the oil. I've never had any issues with this mower until now all of the sudden.
Cleaned, changed oil, now rope jerks back
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BKBrown
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I am not familiar with this particular mower or engine, but it sounds like you may have dislodged or moved something when you had the shroud off during the cleaning, Is there a cylinder pressure release on this engine that might have a spring either moved or dirt under it preventing it from closing ?
Is the shroud holding a part that needs to move freely ? I doubt the oil change caused any problems.
Good Luck finding your problem.
Is the shroud holding a part that needs to move freely ? I doubt the oil change caused any problems.
Good Luck finding your problem.
I continued this morning troubleshooting the lawnmower. I first pulled out the spark plug and pulled the rope...it pulled very freely, but no oil or anything came out of the spark plug hole. I put the spark plug back in, pulled rope, back to same symptoms...about half-way out with the rope and it wanted to jerk back on me. I removed the shroud, looked everything over again (for 3rd time). Brake seemed OK and was working normally, etc. Then, thinking I may have overfilled the oil, I drained about 20% of it, but no help. I started thinking more into the flywheel and whether it could have anything to do with the key (but I haven't hit anything with it...I ran it a few weeks ago just to make sure it started after winter storeage). Thinking at this point I was going to need to drain the oil to keep from it spouting out while monkeying with the flywheel, I got to thinking about the blade of which I had removed to take with me to work on Monday to sharpen on our grinding wheel. I had run the mower before WITHOUT the blade, but I don't recall having had this kind of trouble. I decided to put the blade back on, and WALLAH...the rope pulled normally. I primed the engine, pulled the rope a few times and it started up. I shut it off, restarted it again, wallah. Weird. I guess the blade needed to be on, but, I swear I've run it before without the blade. In any case. I've learned a little bit more about my mower, and more about troubleshooting in general (I'm don't consider myself a mechanic but I'm always up to a challenge). Thanks for your inputs...and maybe someone else will read this one day with the same symptoms and have a "duh" moment too.
RobertBrown
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Thanks for following up with the post indictaing the resolution to your problem. That is useful information, inertia can be a a valuable tool.
BKBrown
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Thanks for the follow up - I don't believe you said anything about the blade being removed. The blade will act as a flywheel weight and keep the engine turning in that direction, yes the lack of that spinning weight could cause your problem. Glad you figured it out ! :thumbsup:
When you grind the blade be careful not to get it too hot, it will remove the temper (hardness).
When you grind the blade be careful not to get it too hot, it will remove the temper (hardness).
The rope jerking out of your hand when cranking is most likely caused from the key that keeps the flywheel in time with the piston-valves has sheared. Remove the shroud, remove the large nut in the center of the flywheel, and then remove the flywheel. You may need to get a shop to pull the flywheel, sometimes it comes off with ease, sometimes not. A repair shop will do it in snap with a puller. There is a groove machined in the crankshaft that matches a groove in the flywheel bore. Its much better to have a sheared key than a broken crankshaft.................. the key costs maybe a buck-50. good luck
I have an identical problem that I noticed yesterday for the first time on a Poulan that I bought a couple years ago, and it has the blade on. I'm thinking wildbill has the answer for me.
The last time I used it, it ran extremely irregularly and roughly - like it was going to die. Almost felt as if the fuel was getting dumped in without appropriate regulation. As you can tell, I'm no lawnmower mechanic. I also noted at that time when I restarted it after emptying the bag, that it would backfire and sometimes sparks would come out. Anyway, I finished mowing, embarrassed whenever someone came by looking at me wondering why I was using a mower that fiunctioned like that. Now the next time I try to use the mower, I get the behavior described by the poster aabove. It pulls smoothly about halfway and then it jerks backwards in a way that is actually very dramatic and hurts my shoulder. It didn't start after a few pulls and it is too risky to my body to keep pulling the pull cord.
So is this in fact probably a broken key between the flywheel and pistons (or whatever). And secondly, is this probably why this mower has been running so bad. Or is it two separate problems.
Thanks.
Rod
The last time I used it, it ran extremely irregularly and roughly - like it was going to die. Almost felt as if the fuel was getting dumped in without appropriate regulation. As you can tell, I'm no lawnmower mechanic. I also noted at that time when I restarted it after emptying the bag, that it would backfire and sometimes sparks would come out. Anyway, I finished mowing, embarrassed whenever someone came by looking at me wondering why I was using a mower that fiunctioned like that. Now the next time I try to use the mower, I get the behavior described by the poster aabove. It pulls smoothly about halfway and then it jerks backwards in a way that is actually very dramatic and hurts my shoulder. It didn't start after a few pulls and it is too risky to my body to keep pulling the pull cord.
So is this in fact probably a broken key between the flywheel and pistons (or whatever). And secondly, is this probably why this mower has been running so bad. Or is it two separate problems.
Thanks.
Rod
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