lawn-boy problems


Old 10-19-05, 06:46 PM
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lawn-boy problems

Have an M-Series Lawn-boy that I am having trouble starting. Two stroke.

When I pull the cord nothing happens. Sometimes it backfires (with the choke closed).

Before this, I replaced the magnito/spark plug wire because the spark plug wire had gone bad. The mower had been getting progressively harder to start all Summer so perhaps my problems were more then just a bad magnito.

Used a business card to gap the magnito from the flywheel and it seems to be working right because I am getting a spark.

I also checked the flywheel key and it looked fine. Replaced it just to be sure.

I took apart the carburator and everything seems to be moving fine.

Took off the muffler to make sure it wasn't clogged. It isn't.

I poured a shot of gasoline directly into the spark plug hole, replaced the spark plug and tried it that way. Nothing. Tried doing the same thing by throwing gas in the carburator throat. Still nothing. Read in quite a few places that if the thing starts up briefly when you do this then you have a fuel delivery problem. But what if it still doesn't start?

Any suggestions?

Thank you for your time,
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Old 10-19-05, 07:31 PM
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have you tried a new plug? make sure the compression is good, 90 should be around the lowest. air leaks can cause problems as well. spark plug may be fouling
Old 10-20-05, 02:06 AM
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Sounds like low compression to me too. Have you checked it?
Old 10-20-05, 02:57 AM
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Being a 2-stroke, and related to the low compression, I'd pull the muffler back off and take a good look at the piston and cylinder. I'll guess you have scoring beyond reasonable repair.
Old 10-20-05, 05:55 AM
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I do have a brand new plug.

I was wondering about the compression. When I pull the cord I can feel the thing drag in bursts, which I understand is indicative of good compression. But on the other hand when I put my thumb over the spark plug hole and pull, I feel pressure but it doesn't go so far as to blow my thumb off. My understanding was that it was supposed to.

Tonight when I get home I will pull off the muffler again and take a look at the piston and cylinder to check for scoring.

Would it be conceivable that you could run into compression problems after trying to start it over and over again. Trying to wrap my head around why I would suddenly have compression problems after replacing the magnito.

As far as timing on the thing goes, like I said, the flyway key looked fine. I was wondering if there was anywhere else in a two stroke engine where timing could be affected, like in the crankcase (I'm new to engine repair).

Thanks again for the responses,
Old 10-20-05, 11:04 AM
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Join Date: Sep 2005
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you can get a repair shop to test the compression, as for internals, a 2 cycle is pretty simple, crank, rod and piston. for air leaks, it can cause a lean condition burning em up.

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