Hello,
This is my 1st post and my 1st atv. 2006 Hensim 150cc that was not running when I got it. I bought a new carb, coil, NGK plug and racing CDI. She started and ran great until about 1/2 throttle, then bogs.

The mixture screw did nothing. After reading 100's of post I concluded I needed more air or a smaller main jet(current is 105). I took off a cheap air filter bought form pep boys and she ran great besides loud popping from the tail pipe. Runs about 35 mph and I am 190lbs and feel as if there is more power there that is lost somewhere.

At this point, I have the mixture screw out 5 turns. If I screw in to 2.5ish as all recommends, she eventually gurgles and stalls. Before I took the air filter off, the plug was black(rich) and I just removed the plug and it was white(lean). Oh, looks like oil is leaking from the head too....kinda scared to hear what this means...

I am going back and forth and need some advice from all you experts. Any and all help is appreciated!

Scott

 

did you get the right size carb? Are you messing with the air/idle screw or the actual mixture screw? To adjust the mixture screw you use the idle/air screw and bring it up to a fast idle. Then you start adjusting the mixture screw until the rpm does not change. then you back it down again to factory and do it again counting the turns each time. once the rpm don't go up any more back it off about 1/4 turn. I have done it this way on 2 different machines. grab a youtube vid so you can hear what they are doing. Just did a quick Google search and it looks like most 150cc atv/scooters use a 110-120 main jet. Jetting kits on ebay are cheep

 

Zrock,
Thank for the reply! I thought i got the correct carb and I am messing with the screw on the left side near the front. The seller said the jet was a 105. I am thinking about tearing down the old carb to see what jet size is in it. So, you think if I got a 110-120 jet, it would become even more rich? She runs rich with the 105 until I added more air (took off filter...I know this is bad). I have youtubed, but to no avail. I am at 2 extremes, lean or rich.

Can I adjust the current jet within the new carb in order to reduce the flow of gas with the air filter on?
Could the new "racing" CDI and orange coil be playing a role in my issues?

I will try to bring to fast idle with the idle screw and attempt to make fine adjustments from there and report back.

I think I am in over my head!

 

i would pull the carb apart and give it a good cleaning. Set all the screws back to factory. verify the jet setting while you are in their. If you bought it used you may have bought someone else s problem. When you say cheep pep boys air filter? what kind of filter is it? If its to small it may be creating a huge restriction. If its a oil bathed filter it could be over oiled.. can u post pic's of the filter and carb?