Lawnmower engine surging - how to fix?
 

At idle the engine in my 2 year old Honda powered mover is surging something fierce. When I engage the blade, it still does it but not as much. I have stuck my fingers into the levers and cables to rev it up a bit, but I can tell it's still surging.

It's got plenty of oil and the air filter is clean.

How do I fix this myself? I don't want to take it to the shop. The grass will be to my ass by the time I g et it back.

I would say Italian tune up. Use it, it will either get better or worse. Either way you'll have done your part.

disconnect the govenor. you should see a bar moving back and forth opening the throttle blade when its about to die, and closing it as it revs. you can disconnect it and maybe run a throttle controll from a local hardware store. this is how B&S motors work, pretty sure the honda is similar

This happened to my lawn mower a couple months ago. I ended up taking it to a shop and they rebuilt the carb for about $60. Now it works like a champ. They blamed the problem on inactivity... I hadn't used the mower in about a year. :) They said even if you don't mow your lawn, you should still start it monthly to keep things in check.

calling Robert Coates!!!

Throw a new spark plug in it first. I even went a step hotter since it was burning so rich.

If that doesn't work, try rebuilding the carb. There aren't many parts. You can probably do it without parts or a manual.

Same problem with my Poulain about 2 years ago. Checked spark plug and governor and both were fine. Did a "rebuilt" of the carburetor and that solved the problem completely. The kits are available from the local hardware store (Lowe's for me). In my case it was just a rubber membrane with some holes cut out of it. Removed 4 screws to split the carburetor horizontally and replaced the rubber piece, while keeping track of which loose pieces were above and which ones were supposed to be below the membrane. Hopes this works for you too.

While reading up on this on the internet before my fix, I read a warning not to run it while it is surging. The surging is caused by the mixture being way too rich and that can wash the oil from the cylinder and do permanent damage to the engine.

I hadn't thought about the washing the cylinder wall issue. Guess it's time to rebuild the carb in addition to the plug.

I say clean out the carb. Used to have this same problem on a Briggs, it would need the occasonal cleanng

Re: Lawnmower engine surging - how to fix?
 

Lawnmower guy here...

The carb is probably plugged up a bit, which causes the engine to run lean, which causes the the engine speed to fall off, and the governor forces the carb to open more, thus the surge cycle begins.

Solution? Clean/rebuild the carb, or buy a new one. If you'll reply with the frame and engine serial numbers, I can get you a price on a new carb. For many Honda mowers, the carbs are cheap enough to simply replace, and easy, bolt-on job.

Try removing the float bowl and cleaning the jets, before going to the trouble of rebuilding the carb. I had a Honda a few years back and had to clean the crap out of the bowl frequently. No fuel filter and a poor tank venting system ensured a constant addition of crap to my fuel.

Sold it and bought a John Deere and never looked back.

JR

Honda engine here, on a commercial grade walk behind snapper...I installed an inline motorcycle filter. I've noticed the float bowl has a drain plug, but never had to use it. I also turn off the fuel to the carb after every mowing, let the carb run dry... So far, so good...no problems. Contaminated fuel in the float can cause problems...

Techron. A couple of caps full. Worth a try. Fixed mine.

Throw it away and move into the city.

Ding! Ding! Ding!! After rebuilding ym carb twice I started using gas treatment in my mower tank never had another problem for 8 years. Doing the same with my new one hopefully I'll never need another rebuild.