yamaha G2 low power issue

[lance192001@yahoo.com]

I have Yamaha g2 cart with new air box and carb. Problem I am having is after installing new carb and air box, cart will only run at rpm if air box hose to carb is completely disconnected. As soon as you put hose on, cart rpm drops immediately. there are no restrictions within air box housing. I have good spark, no restriction with exhaust that I can tell, and cleaned fuel pump with no visual issues found. Vacuum issue? Thanks for any help on this. crank seals?... Issue started before new carb and air box installed and still doing same thing.

[CP241]

is it an OEM Mikuni carburetor? or is it an aftermarket chinese carb (usually "Mokini")

[lance192001@yahoo.com]

mokini

[expo]

Air filter restriction? Did you install a new one? Try running it w/o a filter and see if it improves.

[lance192001@yahoo.com]

new filter, but will not run full rpm unless carb intake is exposed with no air restriction.

[CP241]

Sounds like a fuel/carb issue. If you can get it to run at all with the carb intake hose removed, it should run very very lean and poor. Sounds like it's running super rich, which wouldn't surprise me with those junk carbs.

Try running the motor for a minute and pull the spark plug out.. is it wet with fuel? Do you still have the original OEM carb for it? You're much better off cleaning and rebuilding the OEM carb than putting in a chinese knock off. Their quality if very inconsistent... There's a reason the OEM Mikuni is several hundred dollars, and you can buy a brand new Mokini for $20 shipped.

Also check the plastic spacer between the carb and the head. Those crack extremely easily and will cause you issues.

[lance192001@yahoo.com]

will look at spacer. thanx