[lexmarks567]

I have a craftsman Lawnmower model 917.388400 engine model 143.006714 Tecumseh.
6.75HP. Won't restart. It will Start right up but will pop and and after a minute stalls and won't restart.I Was told its the coil.WHen I got it back from the repair shop for a carb rebuild and busted flywheel key it ran fine.Then It start surging up and down for a minute about a few secunds after startup.Took the carb apart and It fell apart.After messing with it I got it back together.The needle is held to the float with a spring and theat kept coming off.Now It won't stay running.It will start up pop for a minute and stall and won't start back up.I think the coil went bad What do you think.

[kiwiguy]

Sounds more like fuel to me.

The coil would normally stay failed, not be intermittent in such a predictable manner..

[SouthParkXP101]

well you have spark and ignition, sounds like it could me fuel to me too are all your lines clean and clear ,what ,about the gastank is it good and clean , tecumseh, has had a bead reputaion with lawn mowers especally craftsman, next time you buy a mower or such it should come with a Briggs&Stratton ,and in my opinion is the best engine you can get that is small i have a 23 year old briggs magnetron that runs better than any other small engine

just an option next time you buy

[lexmarks567]

Well he said that if it won't restart the coil is bad.If it stalls and restarts the carb is bad.

[SouthParkXP101]

Originally Posted by lexmarks567

Well he said that if it won't restart the coil is bad.If it stalls and restarts the carb is bad.

well one thing to look at is is it worth it?
you can get a new craftsman which is really made by MTD along with murray and others, but however its better if you just buy a new one than replace the coil or carb, you can get a 6.75 HP push mower 22in cut for under 200 hundered dollars

[wfl80]

if the coil is bad you wont get any spark at the spark plug--check several times

[SouthParkXP101]

ok what you should do is , reomve the spark plug and see if you have fuel , tell me wether or not you do

[lexmarks567]

Oh the thing runs.I had it going earlyer.The thing is.It will start but will pop then after a minute stalls.Won't restart without priming.After talking to my buddy he said check the flywheel key see if its cracked or broken.

[ezymony]

The flywheel key is aluminum it is made to shear if you hit something while mowing to keep from damaging the crankshaft. Sometimes it will not shear all the way into but that will cause the problems you are having. I would not put a lot of money into a tecumshe engine they are not very durable the carbs are hard to get right once you start having trouble with them.

[SouthParkXP101]

Originally Posted by ezymony

The flywheel key is aluminum it is made to shear if you hit something while mowing to keep from damaging the crankshaft. Sometimes it will not shear all the way into but that will cause the problems you are having. I would not put a lot of money into a tecumshe engine they are not very durable the carbs are hard to get right once you start having trouble with them.

i agree he would be better off woth a briggs and stratton

[lexmarks567]

Lucky i got 2 back up baggers to use while this is down.I will try to access the flywheel key and post back sometime tommorrow if I have time to access it.

[lexmarks567]

Also the flywheel key is new it was installed back in the spring at the repair shop.

[kiwiguy]

If the flywheel key is shorn and the flywheel has "moved" relaive to it's correct shaft position, there will be either no ignition or poor ignition.

That you have to reprime the carb says that it's more a carb fault to me.

[glenhe]

Hey Dude! Just take the spark plug out and make sure it is shined up. Take a wire brush and wire brush it. I have a spinning brush I put in my drill and I am telling you if a sparkplug is fouled or gapped wrong, your engine will not run right. I am telling you I have had even brand new plugs that I have put in and they got black and would not run right. Always buy more than one plug, because they can be bad from the shelf. I have had mowers not run right after doing all the work you have done too, and all I had to do is pop a new plug in and it then purred like a kitten. They need to be gapped correctly and be clean and unfouled. Also they are correct that the flywheel needs to be in the correct place but from what I read you already replaced the keyway in the flywheel and once that is done it should be lined up. You also stated that the carburetor had already been rebuilt so I tend to believe that is not the problem either. It was also stated that it has run before so the coil should be ok. When you tighten the coil down in position you should move the flywheel back and forth and make sure there is a postcards clearance between the flywheel and coil. If the coil hits, it can brake the keyway again.

[lexmarks567]

Originally Posted by glenhe

Hey Dude! Just take the spark plug out and make sure it is shined up. Take a wire brush and wire brush it. I have a spinning brush I put in my drill and I am telling you if a sparkplug is fouled or gapped right, your engine will not run right. I am telling you I have had even brand new plugs that I have put in and they got black and would not run right. Always buy more than one plug, because they can be bad from the shelf. I have had mowers not run right after doing all the work you have done too, and all I had to do is pop a new plug in and it then purred like a kitten. They need to be gapped correctly and be clean and unfouled.

this is what i get for not updateing. after this thread it went back to the repair shop spent another $74 having the carb redone only to have it surge again. took it back AGAIN and this time he took the carb apart and found the o-rings disintegrating clogging the jets. $25 right there. so now no more problems.