Bought A Foreman 350d With Some Issues

[superrman77 68]

So guys I purchased a 1988 Foreman 350d.  Initially it was running very rich and you had to stay on the throttle to keep it running.  The engine would slightly rev up and down on it's own.  So I dug into it the other night.  Keep in mind I am a rookie when it comes to working on these machines.  I took the carb off and took it apart.  I gave it a good cleaning and ran it through the ultrasonic cleaner a few times.  I looked through all the jets and they were open.  So I put it back together and set my pilot screw 2 1/2 turns out.  I got it back on the quad and it fired right up.  I let it run for 40 min or so and it runs like it should other than the revving up and down on it's own.  Any clue on what could be causing the engine to rev?  I did go through the throttle cable and found no issues. 

[retro 4,072]

Remove & check the rubber intake manifold boot for cracks and reseal it to the head, see if that helps. You can spray some carb cleaner or whatever ya got in an aerosol can around that manifold to check for leaks if you can get to it... before taking it off the head.

[Fishfiles 20,147]

I am no 350D guy , but think they have a  fuel pump , could the problem be fuel flow 

[shadetree 5,969]

sounds like a fuel pump issue, or fuel cut-off relay issue to me.

[Howols 11]

Could be the choke plunger not sealing well.  I had the same problem and a new OEM plunger fixed it.

[Goober 1,555]

Sound like fuel flow issue. 
Does your fuel pump buzz constantly? theres a fuel flow test you can do. A new OEM pump (~$150)—totally worth it don’t cheap out on an aftermarket knockoff

 

is your tank rusty? Sometimes sludge and rust can build up in the fuel suction lines restricting flow—you can clear them with a 1 foot stout piece of pipe cleaner or a piece of cutoff throttle or brake cable. There are intake screens at the end of those lines so watch out don’t pierce them with the cable

 

check your petcock too. Sometimes it gets clogged with debris sucked into it. That debris can cut the petcock seal.

 

clogged fuel filter

 

cracked fuel lines (petcock and fuel intake) can lead to loss of suction 

[superrman77 68]

Thanks for the replies.  I sprayed around the intake and didn't see anything.  Supposedly the fuel pump was replaced with an Oem but who knows.  I have a new fuel relay laying around if I need it.  I'll keep digging into it.

Thanks 

[shadetree 5,969]

2 hours ago, superrman77 said:

Thanks for the replies.  I sprayed around the intake and didn't see anything.  Supposedly the fuel pump was replaced with an Oem but who knows.  I have a new fuel relay laying around if I need it.  I'll keep digging into it.

Thanks 

if its a china fuel pump from ebay ( about 20 bucks ? ), they wont last no time. and now after checking with partzilla, i see they jacked their pump prices up another 30 bucks !!, i bought one the other day, about 130, now they are over 167 !..lol.