On Mar 19, 8:26*pm, deuce wrote:
I have a Honda EB3000C generator with a Honda GX200 motor. *It's only
a couple of years old and has very low hours. *I decided to drain the
fuel and refill with fresh fuel. *It had sat for about a year. It
wouldn't start at first but I sprayed a shot of Gumout into the carb
bore and it started on the next pull. *So I let it run for about 10
minutes and it ran beautifully. *I decided to drain the carb so I
siphoned out must of the fuel in the tank, restarted the motor and
shut the fuel supply valve off. *It ran for about three additional
minutes but instead of stumbling and dying like I expected it started
to backfire very loudly so I quickly turned it off. *I thought maybe
some water had gotten into the fuel so I drained the sediment cup and
the carb bowl. *I put some fresh fuel in the tank and tried to restart
it. *It would start and run maybe 2 seconds, then backfire and die.
Thinking there still may be some water in the carb I redrained *the
sediment cup and the carb bowl and tried to restart. *Same thing, run,
backfire and die. *I added a little Heet to the fuel, repeat drain and
restart - same thing. *I'm thinking the original backfire episode may
have damaged something but before I tear into it further I thought I'd
solicit any experience anyone might have with a similar problem.
Thanks in advance.

Backfire is usualy ignition related as in timing or the ignition
module failing or a sticking valve, you might pull the plug and ground
it then have some one pull the starter to see if its a weak spark
indicating the module. Sears has a 4$ inductive spark tester , it
looks like a writing pen you touch it to the plug wire when its
running it should show if its electrical by the missed firirng
pattern. A compression test might or might not reveal a bad valve.
Misfire-backfire was my ignition module and coil on several other
motors, I dont think its fuel related, on lawnmowers after you hit a
rock and stall it the timing can shift and cause missfiring, but a gen
cant be stalled like that. New engine oil like mobil 1 , and spray in
and kill the running motor with Fogging oil might free it up if its a
valve. That 4$ sears tester will pay for itself on future plug, coil,
wire issues on any motor, it just save me 250 on my car, a guy wanted
to replace what was not wrong, it was one 40$ coil.