[347MudTruck]

I just picked up a 04 rancher from a older gentleman. Its only got 1200 miles and 240hrs. Really clean for the year, but it's running rough. I took the tank and cleaned it good and flushed it with good gas. I cleaned the carb, it was gummed up pretty bad. Also put a new plug in it. The atv will start and idle fine with the choke off but will not rev up. It spits and sputters and will die unless you back off the throttle. It will rev up somewhat with the choke pulled out some. But will still not rev all the way up. Is it worth rebuilding the carb or just buying a new oem carb? It will idle all day without the choke but will not rev up much but just a little. Any other problem that could be causing this?

 

[347MudTruck]

I pulled everything back apart today and used compressed air just incase the carb cleaner missed some gunk. But it still did the same thing, it really confused me so I tried everything that came to mind. Finally I started messing with the airbox and factory snorkel or water guard. With the end of the snorkel partially closed it runs great and will rev up like it should. Does this seem strange to anybody? Its like it was getting to much air and with it partially blocked it seems like it evens out the airflow or something.

 

[Goober]

My thought is that the carb still has clogged dirty jets. needs a good rebuild and possibly a new choke valve and primer plunger. About $100 in parts—you could replace with OEM carb if 1) maybe you don’t want to DIY or pay the shop $275 to do it for you and 2) you can find one.

carb 15yo probably due for some new seals. Get an OEM seal kit from parts links below in my signature block. Or a Shindy kit with new jets and seals for ~$25. Choke valve ~$40; Primer plunger is another $30.

Completely take it apart and clean parts with Berryman Chemtool.

there’s a couple carb rebuild threads here. As you’re looking for OEM parts i agree they offer best performance and reliability

 

[shadetree]

@ OP, you can purchase the oem plunger from partzilla, rocky mountain atv for around 55 bucks, or..buy a china one from amazon or ebay for under 10 bucks. yes I know I tell folks to use oem, stay away from china products at all cost, but this is a case where you do not need to spend high money on a part you will never ...EVER use. unless you live in Alaska ?, there will never...EVER be a reason for you to use this part.