Honda 'surging' at partial throttle

[arceeguy]

Hmmmmm - after re-reading this thread and picking up the fact that this is a brand new engine - the carb should not be in need of a cleaning.

However, it does still exhibit signs of running lean at partial throttle. A properly running engine, even with governor, should not surge IMO. If the temperature is very cold, it could upset the fuel mixture as these engines are jetted lean for emissions reasons - and cold air will exacerbate the problem. Honda may offer different jetting to compensate for varying operating conditions. (low temperature, high altitude, etc.)

 

[Sketch]

I saw in several threads where people thought the treatment (can't remember what it was called) could cause a brand new engine to need it's carb cleaned. I can certainly remove the bowl and maybe dig a little deeper.

I will also try what I saw recommended to check fuel flow - just get a jar (or in my case, nice stretch of gravel on a country road...) and disconnect the line and see what it looks like. The see-through filter certainly looks totally clean inside.

And yes, I have confirmed with a couple more tests, at WOT there is no surge going on.

Thanks for the help.

 

[Egor]

The carbs are poor. I had to fool around with every part of the thing to get mine to run. It is the dumb C.A.R.B laws they have them leaned out so much to meet the law it makes for a just barely running engine. I put a small piece of wire in the air bleed hole to fatten up the mid range, now it just about perfect. It needs the two small holes next to the butterfly in the runner enlarged. That would not be easy. Try running the choke part way on and see if it gets better, that is the indicator. Have fun, Dave

 

[ocscully]

Sketch,

Any update on what you found to be the problem or what you did that seemed to fix the problem?

ocscully

 

[loquin]

Which Honda are you talking about, BTW? I don't think the GX35 has a governer, but, the GXH50 does.

 

[Old Bob]

No govenor on the GX35, in any case surging is not normal operation for a govenored engine, as mentioned before its a mixture problem.

 

[professor]

My 2 cents- I bet if you richen the main jet, the problem goes away. My HF was real lean - had to choke for a long time before it would take throttle. Opened the jet 3 thousandths and all is well.

 

[Danny3xd]

Not a suggestion but I am re-learning that a brand new engine always seem to have some sort of growing pains. Just a thought.

If I remember correctly my new GX50 had a bogging problem that disappeared after a few hrs.
Another thought/question, does she vibe hard at mid range?