New, Need MAJOR Help
 

I just joined, looking for some help. I have an old tomberlin crossfire 150 go cart. A while back it started sputtering real bad, i tore the engine down to the crank and didnt find any problems. Ive cleaned the carb, rejetted for straight pipe exhaust and custom high flow intake, still no help. Yesterday i noticed a lot of...maybe exhaust fumes...comming out of the tube on the valve cover, right after i crank it up. I cant figure out whats wrong with this thing, its getting warm nd i want to ride. Any help at all is much appreciated.
Thanks

Check your valve adjustments (.003 intake,.005 exhaust), some smoking and a little oil is to be expected from that tube.Does it still sputter?

I am curious what your original jet size was and what you put in place of it.

Also, under what conditions does it stumble? Does it fire easy and idle or doesn't do anything right? Idles fine but falls on face when you stop on gas?

I was planning on checking the valve adjustments 2morrow, thanks tho i didnt know what it needed to be

I think it had a 114 original jet and i put a 130 in, but that was after it started messing up and i thought that might help it. It can crank up and idle fine, i can rev a lil and it sounds fine, but when i take off or stomp on it, it sputters real bad and i cant get up to any real speed and it dont have much power

if i get the engine back together 2morrow then ill try and take a video of it

your main jet is way to big. The only buggy we have owned that we could get away with making that big of a jet jump was in fact the American Sportworks machines like Helix and Carbide. That is because their carbs are slightly flawed. Go back to the 114 or whatever your original was and work your way from there. You need a good baseline.

Did it run fine when you first got it?

i got it brand new a few years ago so it ran perfect then, i tried it with the original back in and it didnt help any

Did it sit for a while between the time when it was running great and the time that it started running bad?

No i was driving the crap out of it, started actin up 1 day so i put it up, then the next day it was fine for a while then it started actin up again so when i got stuck and got pulled home i just hosed it off and parked it. it aint ran worth crap since then

oh and i put it back together today with the original jet, ran worse and could barely move

I might want to add that i was mudding them days and afterwards i pressure washed it, so could it be the CDI, or maybe the coil?
Sorry no video i washed my truck and didnt get around to the video

not likely the CDI. Generally speaking, when the CDI goes...it goes. When they go you simply have no spark at all. It is possible that you have an ignition problem but if I were you I would borrow a compression tester from someone and see how much compression you have. Typically when you have an weak ignition it will show under load by spitting and sputtering.

Make sure you inspect the carb boot real well as well. May be a crack there.

yea ive dont checked for cracks on that and replaced the o-ring

today i adjusted the valves to intake .003 and exhaust to .005, sprayed all the electronics down with electrical contact cleaner. now it idles fine but when i give it any gas it just bogs down and dies

Sounds like carb.

TOM

nope, not the carb, i just got done replacing the carb, baffling the exhaust for backpressure, and adjusting the valves to .003 and .004
anybody got any other ideas, still idles fine, but when you try to go anywhere more than like 5mph it sputters real bad

i might be able to get a video sometime next week since the exhaust is quieter now

Have you done a compression test yet? If so what was it? If not you need to just to make sure your making enough compression. I would also check the coil and make sure the 2 wires on back are making good contact and not corroded. Also I hope that when you cleaned it the engine was not hot.

TOM

i dont have a compression gauge but i might be taking it to my buddys stepdad who used to build and race go karts so he might have one, the wire has good contact and the engine wasnt hot when i tore it down

Edit - oh you mean when i washed the cart, no it sat for a while, maybe 45min-1hr before i washed it

alright i think this engine is very touchy, the wires on the back of the coil were so tight that i had to pry them off with a screwdriver, but then i did i sprayed it all down with electrical contact cleaner, crimped the female connectors tighter, stuck them back on and now it runs like a champ... for about 15min until i broke the chain...haha now this chain has 3 master links on it

:hooaray::lmao: Glad you got it running.

TOM