Recently picked up a 93 fourtrax 300 4x4 that had been sitting for several years. Took the carb apart and it was a mess. Lots of corrosion to the aluminum body. I went ahead and cleaned it up and put a rebuild kit in it. Got the ATV running but it doesn't rev up very high.
So I'm going to get another carb to try. The question is are the aftermarket carbs on ebay any good or should I be looking for a decent OEM carb?
No i would never use an aftermarket carb. You can’t get them to fit your throttle and choke cables or rebuild kits for them.
I would definitely find a used OEM carb–Keihin VE90E right? i bought a parts only VE90E for my 93. But i also put in a quality OEM starter valve, primer pump and Shindy rebuild kit. I cleaned it with swabs dental brushes and pipe cleaners. So i have $100 in parts alone; not cheap but works great.
Maybe you didn’t get a good clean on it or it’s not tuned correctly? Just like swamp mud the residue sticks to the passages. Is the passage plug installed? Hole in the vacuum piston diaphragm? Take it all apart and add to this thread so we can see what you’re doing.
Tuning. Set the pilot jet just like the manual says–2 turns out? You have to preset the throttle cable on the handlebar to a slightly tighter than neutral position. Make sure the carb idle screw is barely touching the throttle arm. Put on the cable and get it screwed down onto the carb–this usually puts tension on the throttle cable opening up the throttle–then you can back off the throttle cable at the handlebar to a more neutral position. Install the choke cable and now you’re ready to install the carb.
Oh this pic doesn’t show the passage plug—it was missing when I bought the carb!!!