Honda EX650 Gen will not rev up

[Woodie]

Hi there,

I have a Honda EX650 generator that had been running fine for years, then one day when I went to use it to charge some batteries it would barely run at all. It ran fine the day before, then that day it would start but not rev up. I have faithfully changed the oil and cleaned the air filter on schedule since we bought it new about 5 years ago.

It will start, but it will not rev up - it just sort of sputters along. As far as I can see the choke is wide open, as is the throttle. I ran it with the air filter off and it is spitting fuel out of the carb. I have also put a brand new spark plug in it - no change in how it runs.

The local Honda repair shop suggested checking the exhaust to see if it is clogged, so I removed the muffler and header pipe and ran it without them - it still just sputters along.

I am wondering if perhaps it has a stuck or burnt valve.

I tried checking the compression and it is low - only about 30 psi, but the Honda guy told me that he thinks they have something that reduces compression when starting. Any ideas about that?

This generator ran perfectly until the day it started to barely run - there was no warning, gradual slow-down, etc. It is very weird.

I'd really appreciate any suggestions before I dive in further and pull the cylinder head off. I'd like to avoid that if at all possible!

Thanks! KW

[Airspeed]

My honda E300 was behaving similarly,
It ran great one day but the next time I used it it would start and sputter and finaly die then it wouldnt start at all,
I took it apart and found that the timing belt had streached to the point it wouldnt turn the cam correctly.
My honda lawnmower had a similar problem and I found that the key had split off the crank and the flywheel was out of time preventing it from firing correctly.
Maybe you have a problem with the timing, That could cause the symtoms you describe. Good Luck! Aaron