Latest update. I took apart my sportsman 800 efi today. I took the spark plugs out and they looked good and clean. I checked the T-Bap sensor and traced the wires and it was clean and no visible damage to the wires. Next i took the throttle body off. The rumor about the ethanol gunking up is true. When i took the throttle body off there was black gunk on the engine side of the throttle body. I cleaned the throttle body out and got to thinking if that gunk was on my throttle body what do my injectors look like? We all know if the injectors were gunked up it would cause a sputtering. I didnt make it to the injectors yet. Just sharing what i have found so far. Any other suggestions would be helpful. Thanks

 

Yeah, that ethanol is really rough on small engines and boat motors too. If you want to hedge your bets against bad gas, start adding Sea Foam to the tank. Best thing I've found and not too expensive to use. I put it in everything I own that burns gasoline.

 

What does Sea Foam do? I am pretty new to Atv 's when i ask this but mine does not have a fuel filter on it. I got a direct line to the injectors. Should i look at trying to place an in line filter on my atv? I also thought about running some 103 octane in it. Would that be ok or would i burn my rings up? Thanks

 

Dexter, I have the same bike as you, and I had the exact same issues as you, an it was my spark plug boots getting wet, I took the boots off, and blew around the plugs with compressed air, and then I removed the plugs, and I rubbed the end that goes into the boot with steel wool, to clean up the slight bit of corrosion that was on there, and then I put quite a bit of die electric grease in the boot, and I also put some on the plug, and then reassembled everything, it was fine for 2 or 3 months, then I pressure washed it with the side panels off, and it must have got a little bit of moisture in there, because is started doing the same thing, so I just popped the boots off and added some more die electric grease on it, and it has been fine for well over a year

 

sea foam just "cleans up" the fuel, and dissapates some of the water in it, and as far as running 103, I'd just run some Premium gas (93), I wouldn't go quite as far as 103

 

Should I find some kind of inline filter to put on my fuel line since i dont have a fuel filter?

 

What would cause a sportsman 800 to idle high? Would it be a Bad T-Bap sensor?

 

not 100% sure, but was thinking there is already a fuel filter inthe fuel tank. good to know about the black gunk you mentioned w/ this crap fuel as i will next year put some fuel injection cleaner thru the bike. as far as putting higher octang in the tank, it's a pretty much a wast of money as the higher octang is more high performance engines(which these are not) w/ high compression rates. although the higher octang fuel is known to last a lttle longer in loosing points when the fuel has been sitting. what happens to the ethenol gas is that the shelf life isn't very long and the octang level starts to drop very quicky. example if you have 89 octang gas and it's been sitting for a couple of weeks it might be down to 87 octang level when you go to use it. this is why it's so important now to use a GOOD gas stablizer. imo

 

I found this stuff called Stabil that is suppost to offset the ethanol in gas and clean the engine's. I think this will be my next move. Still looking for answers on the high idleing if anyone has any opinions.

 

Can anyone tell me if the T-Bap sensor would be the cause of high idling on a sportsman 800? My sportsman is idling around 1600 and i know thats way too high.