2005 Ranger 500- missing under load, fouling plug
Bought a 6X6 Ranger two months ago. its in pretty rough shape and I've slowly been fixing it up. Took it out camping and had a blast with it, ran good the whole time.
2 weeks later went out again, first day ran fine, 2nd day power was down and had a miss/stutter when under moderate-heavy load. Swapped in the plug from my quad(same number), still the same and quad ran fine.
Got home and checked cam, looks good as is air filter. Figured maybe it was starving so replaced the fuel pump. No change. Pulled the plug again and its black and sooty so I guess its not starving. Pulled air filter right out, with no air filter and cap off filter box engine bogs BAD. With cap on, no air filter runs the same as with filter.
Pulled carb and checked over, all looks good, in fact carb looks brand new as compared to rest of machine.
So is it an ignition problem that is fouling the plugs from unburnt fuel when it misses
Is it a carb over fueling issue? When we did have it out and it was running good we did often smell raw fuel coming from it but the gas cap was cracked to we figured it was from that.
Any suggestions on where to go from here would be greatly appreciated.
I'm tempted to pull the carb from either my 1998 Magnum 500 or 2001 Sportsman 500 and swap it in and see what happens. Any idea which is a better fit?
Also I notice when I first start it up cold it runs decent then gets worse as it heats up.