Kawasaki Mule 610 running rough: Ethanol????

beppington · Dec 6, 2011

I let my carb'd '07 Mule 610 sit in my enclosed barn for about 8 months without driving it, & when I went to fire it up recently it took quite a bit of cranking, then started, but instead of smoothing right out upon starting, & quickly gaining full power as it warms up, it requires partial choke (about 1/2 - 3/4) now to increase RPM above idle. It will idle fine with no choke, & I can even rev it at a standstill (no load), but without some choke it will stall out if I try to move forward. Oddly, once the engine is revved up to a cruising speed, I can actually push the choke off & it continues to runs fine ... until I let it go back to idle & try to accelerate again: more coughing/ sputtering & unable to accelerate.

So, it takes choke to accelerate, but does fine with no choke at either idle or once cruising.

I've put 2 or 3 hours on it since this all started, & it's consistently running like this. There was prob 2 gals in it when I first started it after the lay-off, & I have added new gas to it now (hoping the new gas would sorta thin out the old I guess). Even though I've read that no additives do anything to fix/ save ethanol, I already had some Sta-Bil, so went ahead & poured some of that in the tank. Do you think it will fix itself? Are there any cleaners that might fix it? Will it require a carb re-build??

Any thoughts on this problem would be great.

Edit: Oops, posted this before I saw that EE_Bota responded in my other thread. However, any other ideas would be appreciated.

Dmace · Dec 6, 2011

Your pilot jet is clogged, this is the smallest jet in the carb and allows fuel into the engine when the throttle plate is closed. Since it's the smallest jet, it's the first to get clogged. I don't agree that additives do nothing to offset Ethanol fuel. I've used Sta-bil's Marine Formula which is designed for Ethanol and it works great. Since using it, I no longer need to clean the jets on my motorcycle, snowmobile, lawn mower, etc... after storing them for months.

The Ethanol fuel is corn based so it tends to form algae after sitting. Take apart your carb and you'll notice your float bowl has a slight green tint to it. That's the algae.

Clean the carb jets, refill the tank with new gas with Sta-bil Marine Formula and you'll never have that problem again. If your not going to let it sit for more than a few days then you don't need the additive.

beppington · Dec 6, 2011

Thanks Derek!

The thing is, I never really know when I might go from driving it once or twice a week to letting it sit for 6 months. So, after a a few days of no riding ... go put some Sta-bil Marine Formula in it?

Dmace · Dec 6, 2011

beppington said:
So, after a a few days of no riding ... go put some Sta-bil Marine Formula in it?

No, it won't do much to fuel that has already broken down and formed deposits. It's cheap enough and it sounds like you don't go through much gas so I would just run it in every tank. It's 1/2oz per 5 gallons for normal use and 1oz per 5 gallons for storage.

SKIDOZER · Dec 7, 2011

Try sea foam it actually cleans and stabilizes fuel been around for years.
It works wonders in motorcycles, snowmobiles was first made for outboard motors cost more but works.
Autozone and Walmart have it.

cdaigle430 · Dec 7, 2011

You definatelty want to add a fule stabilizer if leaving it sit for that long. If this is an EFI machine please disregard next comment. If you have a fuel shut off, before you park it and turn the engine off, turn the fuel shutoff-off and let the engine use up the remaining fuel in the carb. Been doing that to my ATVs and equipment for 14 years and have had no carb issues whatsoever. My husqvarna tractor does not have a shutoff and even though I put fuel stabilizer in it I need to have the carb rebuilt next year.

Dmace · Dec 7, 2011

Shutting the fuel off won't do anything but make it harder to start. The fuel in the tank will still create deposits if there is no additive to prevent it.

TOMMYHPX4X4 · Dec 10, 2011

i add stabil to all my gas cans that way if i do use it all up or store whats left i feel safer.better to add it before than fix problems later when you need the machinery. that ethanol eats up stuff in the carb really bad most times you will have to take it down and get a rebuild kit and just redo it.stick with stabil and another thing shop around where you buy your fuel there are lots of stations that sale pure gas with no ethanol. if it's a daily driver like a car or truck ethanol isn't that bad but set something up for a week or two maybe more and you could do alot of damage to the fuel system.