New 88cc motor in ATC70 running issues?? Expert advice needed

[max]

I have a new 88cc motor with 22mm racing carb. It starts up and idles perfect. But it wont take any throttle (wants to stall). When I choke it she idles way up. But takes a little throttle (but will still want to stall). I have played with needle and made one A/F adjustment. Not too much of a change at all. Am I looking at more of a air/fuel adjustment or main jet issue?

Only reply if you have experience with bigger motors on 70's

Thanks
Max

[Vealmonkey]

Have you pulled the plug? If the plug is sooty black or chalky white, jetting issue. Some of these so called racing carbs, aren't the best of quality. Also check all you connection joints from the carb to the head to make sure of no air leaks. Make sure your throttle cable is properly adjusted, barely any slack. Also before running the engine, make sure the throttle cable is raising the carb and that the carb slide or throttle cable isn't sticking. I've seen it happen before.

[max]

Veal. I have checked the plug. It looks fine. Almost like its not getting enough fuel. But with this carb on the little 88 motor i would think it should be fine.

I have checked for air leaks with the manifold....no problems.

Every time i have to make a A/F adjustment i have to pull the carb. It sucks. I have ordered 4 motor/carb aftermarket kits. Have not had one where we had to make any adjustments. I just didnt want to think into this whole situation to deep if someone ran across something simple or FOR SURE!

[Vealmonkey]

Are you running with the air filter on the engine or air filter off the engine. Try running without the air filter and see if it runs different. Try running without the gas cap and see if it runs different. And just cause it's a new carb, doesn't mean that it couldn't have issues. Make sure fuel line isn't kinked or collapsing in on itself. Install one of those cheap clear plastic fuel filters to make sure you have enough fuel in the line and have good flow.

[max]

Havent messed with the gas cap yet. I did put a new seal on it though. HMMM! I have plenty of gas to the carb. Filter on and off didnt really have any affect. Im gonna mess with the gas cap as i have seen them cause plenty of major running issues. Thanks for chiming in Veal. I will keep ya posted!!

[oscarmayer]

^ updates?
is this one of the TB 88cc upgrades to a 70cc engine? if so, you may need a carb jet kit. we had to rejet the carb for my son's racing quad. BTW, 22mm is really larg eon a 88cc 4-stroker. we run a 22mm on a 125cc racing engine making over 17hp. You may jsut ave too mcuh carb desptie what some of the other places tell ya. Also, if it's the mikuni, it's too big, if it's a china man 22mm it's really more liek a 19 mikuni so it's ok. ours on my son's is a 22mm mikuni. WE had a 24mm but it would start and idle great then when you gave it gas it died. simular to your issue. the problem was the air outflowed the fuel, when jetted up, there was a hugh flatspot most of the way through mid-range.