engine will not start

[jonbo]

I have a Manco avenger with a Robin 6.5ph engine
It worked great for a while and then lost power and eventually quit running. I took it to a repair shop and he replaced the spark plug and got it running.... for about 30 minutes after i got it home. Now it will not start all. It acts like it is trying to start but just backfires a little and that's it. I have checked that gap on the magneto, replaced the plug and checked for spark. all is good. I chock it and try to start it and it just backfires.
Any ideas?

 

[firemanjim]

I'm sorry no one got to you any sooner... It sounds as if you have a dirty carb. No biggie! Just take it apart and clean it. Replace, and be on your way! If you took it to a small engine guy, don't EVER go back to him.... He should have been able to get it running and it stay running....

 

[minibiker]

Is it hard to pull ? could be a broken flywheel key

 

[Want1make1]

have you looked at the air filter?

 

[BirdFanatic]

Was it losing power over a good time period or did it just lose power really quickly if it did it slow id guess compression and if it did it right away check ur gas tank and clean ur carb

 

[Poboy kartman]

Is it hard to pull ? could be a broken flywheel key

I suspect this too...backfiring is usually timing related....

Another thought: Just to throw it out there....I've never seen a Robin Subaru...but if that's an OHV engine (like I think) ....your valve lash could be off...and your exhaust valve not opening properly....

EDIT: What I normally do is remove the air filter....shoot a little carb or brake cleaner in the carb and crank it...if it runs for a few seconds and then dies.....it's the carb....if it acts the same....it's something else....