lawnboy compression question

[denaman]

Replaced the ignition coil on an M-Series Lawnboy. Wire was frayed. Now I am having a hard time starting it (and I was having troubles before I replaced the ignition coil, so I might have had more then one problem). When I pull the cord, absolutely nothing happens.

I do get a spark, so that is not the problem.

I wonder about the compression. According to the repari manuals I've read you are supposed to test compression by putting your finder over the spark plug hole. It should blow off when you pull the cord. Mine does not. And when you turn the flywheel counterclockwise it's supposed to recoil in the opposite direction if your compression is good. Mine does not. However, on the other hand, another manual said that your compression is good if the pull on the cord is uneven, which mine is. So then I wasn't sure. Can anyone give any further insight on how I would go about trouble-shooting this problem?

What might be most telling is the fact that sometimes when I pull the cord the engine backfires. Is that indicative of anything?

Thank you for your time, Brian

[EXT]

You may have messed up the timing. Check your manual for this.

[ds549]

when new it shouls have 150 pounds of compression on the 2 stroke engiine. 125 pounds will run but is harder to start. lucas

[Greg O]

Not on a Lawn Boy!! IIRC about 80 psi on the two strokes. "M" series, is that a four cycle?? Greg

[ds549]

when new it shouls have 150 pounds of compression on the 2 stroke engiine. 125 pounds will run but is harder to start. lucas Not on a Lawn Boy!! IIRC about 80 psi on the two strokes. "M" series, is that a four cycle?? Greg was justgoing from what iwas told at lawnboy factory school and what is stated in the m service manual . another thing to check on the m is if the ex ports and/or muffler is clogged. lucas

[denaman]

Still no luck. It either does nothing with each pull or it backfires.

Muffler is not clogged.

As far as the timing goes, I removed the flywheel and checked the key and the thing was fine. Could the timing be screwed up internally?

This is, in fact, a two stroke engine.

Brian

[ds549]

if you have good compression and spark, and it wont run with a dose of gas poured in the carb, you may want to take off muffler and see if the crankshaft seal has popped out. there is also a crank seal on the top of the engine. if it does fire up with a dose of gas then your carb may have dirt or water in it. also be sure the crankcase bolts are snug.if you dont have good compression ,nothing on the tuneup end will help. lucas