Yamaha EF2400is Surging Idle

I would recommend putting some SeaFoam (Available at WalMart) into the tank and run the generator enough to get it into the carb then let it set overnight and see if that helps. I add SeaFoam (1oz.) to the tank everytime I add gas. I previously used StaBil but found SeaFoam to work more efficiently since my generator may set a month or two between uses, usually starts on 2nd. pull.

You can find Honda parts at most any gardener tool and repair shop. Can't say if that is true for Yamaha's, but parts for Honda's abound. Including new carbs, if it gets down to that.

I second trying a bit of Seafoam first before giving up hope. You'll more than likely need a pair of 2K watt units to effectively run your AC, a 3K watt unit should be able to do it and Champion does have an inverter 3K watt genny that is priced well below what blue or red offers. Our genny is of 2007 vintage as well and I have always used Stabil and Seafoam to keep it purring along.

Join the club. There are very few Yamaha service centers, and the ones I looked at ship the generator somewhere far away, so it may take weeks to get anything done. I like the 3000iSEB, but were I to go for another generator set, it would be a Honda eu3000i, or a eu2000i pair. Maybe even a eu2000i triplet set so the A/C units that marginally start on 3000 watts wouldn't be an issue.

I've found that Star-Tron seems to work better than Sta-Bil, provided you get a good brand of gas (Chevron.) However, Sta-Bil is far better than nothing. As for cleaning/curing hunting, "Start your Engines" by the Sta-Bil makers seems to have done the trick for me, but I'm sure SeaFoam will help as well.

Thanks for the replies.

I will definitely try the SeaFoam.

But, I don't feel too bad about all this, I've had the generator for over 7 years and it has served us fairly well.

Sounds like it's worth paying the Honda price for Honda quality and service.

We've got a trip to Wisconsin coming up in June, just need to be ready for that :-)

Bad gas?

OP here:

I did fill the tank with fresh gas and SeaFoam, ran it a bit, and then let it sit for 48 hours. It's been running most of this morning, and still surging at idle and on small loads.

Despite my desire to take an 8# sledge hammer to it, I ordered a new idle jet for it, with a glimmer of hope that will fix it.

I'll post back once I install the new jet.

If it was mine and I didn't have a container of carb solvent (I do), I'd take the carb off and take it to a small engine shop for a rebuild. There are probably some orifices clogged in the carb or another issue. I'd also clean the rest of the fuel system and replace/install a gas filter. The price of repair to the carburetor will be a factor of 10 less than a new generator. You'd also get more $$ if selling a working gen set than one with a problem.

Yes it has to be a small clog remaining in some area of carburetor. I'd take it apart and dip the metal parts again. If that didn't work, I'd somehow scrounge up another carburetor. There must be some discount source of Yamaha parts somewhere??

Time for fuel injection on this stuff. All my fuel injected small engines=no more of these problems. Sit for six months without starting=fire right up.

"Time for fuel injection on this stuff."

Amen to that.