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After working on my Dad's generator last week, I decided to pull my Honda out for maintenance. It's an EM5000s, and hadn't been run in about a year. Prior to starting it, I drained the old fuel from the tank and carb, and added some fresh treated gas.

Using the choke, it started on the first pull and went right to "full throttle" (auto throttle off). Ran great, sounded great for about almost a minute. Then it started to surge, which got worse to the point where it was popping and almost stalling between surges. Pulling the choke out some helps, but obviously something isn't right. It seemed to run alright with auto throttle on (idle, no load).

Seems this is a common problem many people are having, with all brands. I've done a lot of searching and reading online, but everyone has their own theory and terminology when it comes to different parts (mixture screws/idle screws/pilot jet).

I'd like to eliminate all possibilities before I tear into the carb. I've already taken the plastic idle screw out (#1 in the photo), and removed the plastic pilot jet (#2) for inspection. The horizontal thru-hole in the jet is perfectly clean, and the o-ring on the end is in good shape. There is a hole in the bottom/end of the jet, but it doesn't seem to go anywhere. I gently inserted a small wire in the bottom end, it felt like it was tacky inside, but I didn't want to press too hard. The idle screw is exactly where it was before removing it, same number of turns out. Was wondering what the part labeled #3 is for. Is it something that can be removed and cleaned? If so, how does it come out? Would be great to know what the correct terminology is for each part.



Thanks again for any advice. I'd like to avoid doing anything drastic with this unit unless it's absolutely necessary... It may be 13 years older than my Dad's, but it was also about three times as expensive.

Carb probably needs cleaned or rebuilt. Could probably just replace. And drain gas before storage.

Try putting it under a load and just let it run, it may just work itself out.

mi79 said:

Was wondering what the part labeled #3 is for. Is it something that can be removed and cleaned? If so, how does it come out? Would be great to know what the correct terminology is for each part.

Click to expand...

#3 is the fuel/air mixture screw; it rarely requires any adjustment, and has anti-tamper "ears" built in to prevent it from being turned too much and effecting the emissions of the engine.

Sure sounds like there is still some debris or gunk inside, blocking or restricting fuel-flow. The main just is suspect, as it has a very, VERY tiny hole that is easy to get plugged up.

A few tips:

Use a real carb jet cleaning tool, not welding rods or the like, to clean out the small holes.
Replace all gaskets when working on the carb; it only takes a tiny leak for vacuum to form and cause poor running performance. Be sure the bolts holding the carb body, gaskets, etc. are secure too, to avoid a vacuum leak.

Seems I may have corrected the problem, but as usual I'm not exactly sure what it was. I ended up re installing the plastic pilot jet after clearing the tiny hole in the end. As usual, it would begin to surge as soon as the auto choke turned off (after almost a minute of running), but it was worse than before.

I decided to dig into the carb, but when I disconnected the fuel line from the carb I noticed there wasn't any fuel in the line (fuel valve was off). Not even a drop came out. I figured I should test the flow of fuel from the valve through the line. When I did this there was very little gas flowing out. Tapping on the valve with the plastic end of a screwdriver must have dislodged something in the valve, as it started flowing normally. I had tested the valve prior, but that was when I drained the tank by removing the debris cup.

Regardless, I put everything back together and ran it for over 5 minutes with a space heater and trouble light connected. Seems to be running well, no surging.

I now have a monthly reminder in my calendar to start and test the machine.

Thanks again for all of the help.

I have a Dayton (Grainger) generator with a 11hp Honda motor. I was having similar issues. It would run best on partial choke, but would surge whenever the choke was taken off. I ended up taking the carb off and cleaning the gunk out of the bowl. I also ran a fine wire that I use to clean out paint guns, through the main jet which was partially plugged. I put it back together, prayed, pulled the starter cord and now all is well. Now I religiously add Stabil, run the carb dry, and start it periodically.
Bruce