# Craftsman 28cc Piston jams at top of stroke



## John Lolli (Nov 3, 2005)

I have a craftsman brushwacker - 28cc model 358.796221. It starts in full throttle mode then quits suddenly and the piston seems to be jammed at the top of the stroke. I can take a wooden dowel and tap the piston back down but it jams again on the next pull. Any ideas where to look first. thanks - john lolli


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## hankster (Jan 1, 1998)

One of two things I would guess.

The ign. module may have come loose and it is hitting the magnets on the flywheel.

It may have some debris at the top of the cylinder that is jamming the piston at TDC. Many times if you look down the spark plug hole you can see damage on top of the piston. If that is the case you'll have to remove the cylinder to see what is causing it.


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## John Lolli (Nov 3, 2005)

Hankster -- thanks for the response -- what is the proper gap for the flywheel and magnets ?


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## hankster (Jan 1, 1998)

About .010 to .015. I just normally take a post-it note, fold it so it is "3" thick and use that instead of a feeler gage... feeler gages don't bend real well around curves.


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## John Lolli (Nov 3, 2005)

I took it apart. First thing I found was a broken gas line from the tank. It was so brittle. Now, it is definitely the flywheel rubbing on the magnets however I tried the post it trick and could not get enough gap so I opened the gap up to the max and the engine spun fine. I dont know if it will run this way and will find out after I get the fuel line. I imagine that I can buy the fuel line in bulk as opposed to going to sears or poulan -- at least I hope I can. It couple be possible that there is some play involved. When I gapped the ignition using the post it, I thought I had fixed it but then it hung up again on the magnets. I will try a feeler guage unless you folks have another suggestion. The magnets are real strong and it may work in the max position.


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## Viper32 (Sep 18, 2005)

John Lolli said:


> I took it apart. First thing I found was a broken gas line from the tank. It was so brittle. Now, it is definitely the flywheel rubbing on the magnets however I tried the post it trick and could not get enough gap so I opened the gap up to the max and the engine spun fine. I dont know if it will run this way and will find out after I get the fuel line. I imagine that I can buy the fuel line in bulk as opposed to going to sears or poulan -- at least I hope I can. It couple be possible that there is some play involved. When I gapped the ignition using the post it, I thought I had fixed it but then it hung up again on the magnets. I will try a feeler guage unless you folks have another suggestion. The magnets are real strong and it may work in the max position.


I always use a Business Card to set the gap, has worked perfectly for me for years.

Viper


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## bugman (Aug 12, 2004)

i've always used a dollar bill............., get it as close as you can without rubbing or catching, i doubt it'll run that way you have it now, it needs that coil close to the mag for a good strong spark to ignite the fuel.


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## hankster (Jan 1, 1998)

If you set the gap properly with the post-it (or even a card) then it shouldn't hit the flywheel. Could be a cracked crankcase that is allowing enough flex so when the magnets pass it is pulling the ign. module into the flywheel. Turn the engine over slowly by hand and look to see if the ign. module is being pulled into the flywheel when it passes.

You should also check that the primer is working properly. Those units are so old that we find the rubber plunger in the primer is brittle most of the time. Parts are no longer available to fix the primer on those models.


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## John Lolli (Nov 3, 2005)

Cracked Crankcase -- hmmm. When I first tried to loosen the screws on the ignition, I was surprised as the screws were very tight. I had to use a 3/8 ratchet and screwdriver attachment to loosen them. The ignition could have been pulled to the flywheel magnets because as I said -- the magnets seemed very strong. I will look for the cracked crankcase. The primer did appear to be working.


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## John Lolli (Nov 3, 2005)

Fuel lines were brittle and broke - replaced fuel line from tank (inlet ?). Does this line go to the right side or left side nipple with the burshcutter in the upright position (Handles facing up), There are two nipples one for the primer line and one for the inlet line.


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## John Lolli (Nov 3, 2005)

I got the fuel line info from another post on this board. I got engine started however it has jammed up again. I tore the unit down and found metal filings etc inside the block. The bearings on the connecting rod at the crankshaft side are gone. They were falling out. The crankshaft appears to have been rubbing on the piston skirt. 

Now, how do I change the connecting rod. There are no cap bolts. I have separated the block but not completely as I cant remove the key on the crank and cant get the crankshaft bearing over the key. How do I get the key out ??? Also, if I could get the centrifical clutch off I could mybe separate the block from that side. How do I get the clutch off ?? Lastly, it almost looks like the crankshaft is in two pieces which would explain how to remove the connecting rod ?? If that is not the case, how do I remove the connecting rod ???


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## John Lolli (Nov 3, 2005)

Well got the whole thing completely disassembled. Just learned that the parts are no longer available from sears or poulan. Anyone have a 28cc engine laying around they want to sell.


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## hankster (Jan 1, 1998)

As noted in an earlier message, few (if any) parts are available for this unit. It is unlikely you will be able to adapt another style engine to this unit. Best bet would be to scrap it and get another.


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