03 sportsman 600 power problem

hello. I have an issue with my 03 sportsman 600 that my mechanic cannot figure out. i'll do my best to explain. i hop on my quad when engine is cold. start it up and i run it down that road say about 40-50 mph. everything is fine until i hit somewhere around 1 mile. then all of a sudden i have no power. the engine acts like it has a fuel restriction. it putters and putters. it does not die, it just does not let me rev very high. maybe 15mph is the top speed at this point. if i push the throttle more it just putters. this only happens at high speed down the road. i never have a problem putting around my property. i can run it all day just pulling a trailer at low speeds and have never had a problem. if i park the quad and let the engine completely cool down and try it later in the day, again everything is fine till about 1 mile down the road.

this is very annoying. so far the only thing I've done is change the fuel filter. my mechanic has no suggestions for me. others have pointed to vapor lock. then others say, "no way, do you know how hot the fuel would have to be for it to be vapor lock?"

so I'm look for suggestions. has anyone had this problem and successfully fixed it?

thanks
adam

Sounds like your pickup coil is going bad. I'm sure it is an electrical issue by the "cool down and its fine" statement.

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Originally Posted by Matt150

Sounds like your pickup coil is going bad. I'm sure it is an electrical issue by the "cool down and its fine" statement.

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thanks, I'll investigate that.
adam

the problem still persists. when I run down the road and it starts acting up, I can pull the choke and it clears right up. then of course when I slow down and stop, the engine dies. so I have to remember to push the choke in before I stop.

adam

your gas tank may be vapor locking (and it dosnt take excessive heat to vapor lock) your vent may be plugged...when this happens remove the gas cap and see if the problem clears up...if it does remove front plastics and see were the little vent line from the top of the tank is blocked of or just replace it

Quote:

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Originally Posted by spyshot

hello. I have an issue with my 03 sportsman 600 that my mechanic cannot figure out. i'll do my best to explain. i hop on my quad when engine is cold. start it up and i run it down that road say about 40-50 mph. everything is fine until i hit somewhere around 1 mile. then all of a sudden i have no power. the engine acts like it has a fuel restriction. it putters and putters. it does not die, it just does not let me rev very high. maybe 15mph is the top speed at this point. if i push the throttle more it just putters. this only happens at high speed down the road. i never have a problem putting around my property. i can run it all day just pulling a trailer at low speeds and have never had a problem. if i park the quad and let the engine completely cool down and try it later in the day, again everything is fine till about 1 mile down the road.

this is very annoying. so far the only thing I've done is change the fuel filter. my mechanic has no suggestions for me. others have pointed to vapor lock. then others say, "no way, do you know how hot the fuel would have to be for it to be vapor lock?"

so I'm look for suggestions. has anyone had this problem and successfully fixed it?

thanks
adam

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intake boot between carb and enginge is cracked. it will be sealed up when cold and stiff but as it warms the crack opens causing a lean condition which is aided by pulling the choke. you may have to remove intake boot to see cracks.

I had that problem with my 500, turned out to be bad fuel pump.