GT2550 engine surges and stalls at lower RPM's

[Lead-Cons]

Hello:

I have a GT2550 (about five years old). Just recently, the engine surges then almost stalls at lower RPM's. It will also backfire and sometimes actually stall out.

If the engine is under load (moving or with the PTO engaged) or at sitting still at higher RPM's it seems fine.

I have replaced the air filter and cleaned/reoiled the pre-filter. Cleaned and gapped the plugs. Yet still the problem continues.

I am going to replace the fuel filter next. But I hope someone here may have some ideas.

Thanks!

Tom

 

[rcbe]

would suspect dirt/water in carb or fuel supply. remove/clean/rebuild carb with new kit. drain/clean fuel tank/lines. drain/clean fuel can.

 

[OldMachinist]

Sounds like some dirt in the idle passages of the carburetor. My 23hp Kohler Command did the same thing a couple of years ago. I took the carb apart, cleaned and blew it out. It hasn't happens since. Does it smooth out if you pull the choke on a little?

 

[Lead-Cons]

I did try pulling out the choke a bit but it promptly died when I did.

I will drain and clean the tank and lines and install a new fuel filter. I am using 10% Ethanol Fuel...could this be an issue?

 

[OldMachinist]

The ethanol fuel is only a problem if it goes bad. It only takes around 30 days for it to start going bad in the fuel system.
You could try running some Seafoam additive in the fuel, its good at cleaning the small passages in the carb.

 

[Leo Rabon]

It sure could be a fuel problem with ethanol if it is 30 days old or so. It will certainly absorb moisture and thus, water in the fuel. I always add a good quality fuel stabilizer to the fuel. The other thing is I switched to 100% gasoline (no ehtanol) for my small engines. I see a world of difference and I don't have to dump fuel that is several weeks old. With the fuel stabilizer and tight cap on the fuel can, it is as good as new. Got my son switched over to 100% gasoline and he is a believer now. One other very "controversial"
item is I use "93" octane. You can get a lot of different opinions on this item but I have a relative that owns a "small engine" sales and repair service (20 years) and he advised me to do this. The octane depletes rapidly on fuel so if you have 93 octane today, you may have 90 octane within two weeks. He laughs "all the way to the bank" cleaning fuel systems, tanks, lines and carburators on small engines from the affects of ethanol. If you can't get 100% gasoline be sure to get 93 octane "whatever". You can check the internet for 100% gas stations in your state and area.

Leo

 

[Lead-Cons]

Hi all:

Here in Vermont they had stopped selling non-ethanol gas, at least locally. Then I was told the stabilizer I was using was not meant for ethanol gas so I stopped using that as well.

Since then, two stations locally are selling Premium only non-ethanol, so I guess my mowing will get more expensive. But also is there some sort of ethanol specific gas stabilizer?

If the heat breaks this weekend here (and it is supposed to) and I find the time, I will drain the tank and lines and install a new filter. Then run the non-ethanol Premium. I will write back the outcome.

Thanks again to all....

Tom

 

[OldMachinist]

The Sta-Bil marine formula is for ethanol blended fuel.

http://www.goldeagle.com/brands/stabil/products.aspx#marine_formula

 

[Leo Rabon]

For what it's worth:

If you are planning on changing the fuel filter, be sure to use a Kohler OEM, fuel filter. This is based on the many other threads I have read about the "finiky" Kohler fuel filters. They say they have experienced engine running problems with the non Kohler fuel filters and when they replaced with a Kohler OEM, the problems disappeared. I hope everything works out.