ok so i was reading through the thread Max Gara had on the same generator, and i came across this site while looking for solutions to the generator running.
ok so a friend of mine Ian has a GMC 750w genny, and he has the exact same issues he was thinking it was the coil and so i said i will take a look,
so it has a coil and a cdi module and a stator so it seems like its adopting the same set up as a motorcycle so i checked all ignitions areas even removed the flywheel and no issues has nice spark, checked and cleaned carb, no issues there checked and cleaned muffler yes was caked up with oil and carbon but i had it running for half an hour before it stopped working which i was amazed it actually would run with no work to it at first. well anyway so i checked the tank nope no issues i cleaned the sediment bowl that near the tap nope had a little bit of dust and rust flakes but no issues as it had run before i dug into it deeply. i had the front panel off no issues there the switch works as it should.
had the head off some carbon but no issues and thus reinstalled after cleaning,
tried different plugs still the same it would fire for a couple of seconds and then stop..
this is where it gets funny, so i had some atf in a squirty bottle so i though ok squirt some down the carb and well it was a little smoky but it would wanna run but still not continue to run... so dumb fool me forgot i got a compression tester. did the compression test 95psi... so did a google and see what is ok for a two stroke... and well well 120-150psi so she is down quite low, its low enough according to a google search to barely want to run if it can run. ok so i never took notice of the bore at the time as the motor looks like its only done so many hours and looked in a reasonable condition... well yeah maybe not the case so id say its done a fair few hours and the rings are at the rooted stage, so him mucking with the ignition would prove useless and a waste of money.
so i got the bad news to tell him about it, now cause its such a long time since it was made im gonna bet you cant get a set of rings. so watch this space i have a few more tricks i can try to get it to run once again.
i hope that max gara is still on here he can follow in on this topic, i dont like to walk away from a engine until ive exhausted all my possibilities im around 12hrs of mucking with it so far so each arvo for about 4 hrs i work on it.
but off the subject i have got another motor he gave me to keep a 5hp briggs and that will not wanna stay running and leaks badly around the updraft carb so im putting my money down that its a compression issue as well as everything seems fine on that engine.
Tony.
