Chainsaw Dead

[Lawrence]

My chainsaw was fine just three weeks ago, but refuses to do anything now. I've cleaned and reset the plug ( it was wet and carboned). I checked the bore through the exhaust port - looks clean. unscored with top ring intact). It feels like the compression is ok. My guess is the spark (or lack of it) or the carb (but there seemed to be plenty of fuel on the plug. What is the best way to test the spark without giving myself a shock? Any other ideas? The machine is a Dynamac, about 9 years old from Machine Mart.

Thanks

Lawrence

[JimK]

get a mate to hold the plug (out of the plug hole but still connected to the HT wire) against an exposed metal part of the saw (if there is one?) - he holds it whilst you pull the starter cord - it will spin easy as you have the plug out so no compression...

ISTR any shocks are not going to harm you (or mate :>) unless they/you have a heart pacemaker.....:>(

Cheers JimK

[tony sayer]

Better still wind a bit of wire around the metal screw part of the plug and connect that back to the metalwork of the saw that way theres less likelihood of having either yourself or M8'ty dancing around;)...

[Andrew Mawson]

anything now.

checked the

What is the

Best test for chainsaw compression is will the start cord hold the weight of the saw. Rough and ready but seems to work in practice.

AWEM

[Weatherlawyer]

Sounds like you have a mixture problem. Either that or sediment. Check the air filter.

[Jules Richardson]

I just went through this with my lawn tractor a few weeks ago - compression seemed reasonable, but after systematically ruling out everything else, I pulled the piston; turns out there was a huge gouge down the side of it, and a matching on in the bore, so something had got in there. It was right at the bottom of the stroke, and not visible by just looking down the bore with the piston in place.

That's just a FYI; chances are it's a spark or fuel issue, so do check those first (secure the plug with a wire, as others have said). For testing, dump some fuel direct into the cylinder and see if it'll try to run, or dump carb cleaner / propane / wd40* into the air intake and try firing that way.

• one of the few things it's good for... :-)

Other potential gremlins: bad head gasket, bad valve seating, timing out due to sheared flywheel key (assuming magneto-derived spark from magnet in the flywheel).

cheers

Jules

[Lawrence]

Spot on. Air filter it was. After a wash and blow out, the machine fired first pull.

Thanks for all the suggestions.

Lawrence