I bought a baja 90cc 4 wheeler today at an auction it runs but only idles, If I push the throttle it spits and sputters. I cleaned the carb twice and tried to adjust the jets but nothing helps I have rebilt car engines but this thing is kicking my tail! if anyone has a suggestion im all ears. thanks

 

This might sound silly, but did you clean the air filter? Is the choke on (or check to make sure it functions properly) You might also check the fuel filter. Is there water in the gas? The easiest way to check for water in the tank is to put the fuel petcock on reserve, and drain about 4 oz of fuel into a glass cup. If there is water, it will form little beads at the bottom of your cup.
Hope this helps

 

thanks for the reply,yes I tried all that you mentioned I talked to a guy today that told me to adjust the needle in the main throttle body that didn't work either but i'm still open to anymore ideas.

 

forgive my ignorance...
Is it a 2 stroke?

 

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Ok, I'll give a 4 stroke a try. [img]i/expressions/face-icon-small-smile.gif[/img]
Given there is no carb problem, make sure the rubber boots for the carb are not cracked. After that, A compression test. Providing all that is good, it has to be in the valve train. I'm unsure of the design, meaning I don't know if it has a cam chain/valve adjustment/timing/etc.

 

first things first, the baja has the same engine as the sunl, kazuna, and all the rest of the chinese 90cc atv's, now things it could be, carb still has dirt in it and is still plug somewhere, fuel filter needs replacing, gas cap vent plugged, spark plug fouled, fuel line pluged or kinked, needs vave adjstment, worn rings or leakey vavles = low compression,

 

I bought a new carb just to rule all those things out it didn't help! now I have moved on to the cdi box whatever that is.But I will tell you this it is the last thing I buy for this thing unless it's a match and gas.I'm still open for any ideas.

 

I'm sorry it is a 4 stroke and I have adjusted the valves,checked the time,cleaned the airfilter,cleaned the gastank,checked the gascap and anything else that I can think of but still up for any ideas thanks for your help.

 

This may not be the problem, but my son's 90cc quad stopped running, and after a little investigation the problem turned out to be the choke on the carb had came apart and was stuck on. Living in hot AZ I just removed it and now it runs great.