Motor getting too much air
 

I'm stumped again. My cart started acting up lately. When I throttle down, it has trouble getting up. Like it sputters and chokes, never getting top end. If I pull the choke and keep it choked it run great. I've checked hoses and air filter and box. Also, weird as it sounds, with seat open it runs fight, when I sit on it to ride is when it chokes up and sputters. G9 by they way. Any help appreciated

Re: Motor getting too much air
 

Could be a crack in the rubber between the carb and the cylinder. Or crank seals. Definitely sounds like your getting air somewhere if the choke helps. Get some starting fluid and spray it around different areas while it's running. If it sucks in the fluid it'll rev up a little. That's a good way to find various leaks. Don't run it for long like that. Lean conditions can cause excessive heat as well.

Re: Motor getting too much air
 

Don't forget to look at the famous yamaha phenolic carb spacer.The get real brittle with some age.

Re: Motor getting too much air
 

Right, its usually either the carb spacer is cracked...you do not tighten that thing very hard. Or, its a leaky airbox. The airbox needs to be tight and together right all the way around or it runs poorly. Get new pulls for it or bungee it down tight, make sure the rubber elbow inside is in right, its a pain but it has to be right.

If that is not it I'd clean the carb and check the float level and condition, then I'd check all the fuel hoses for cracks or leaks, but usually fuel supply issue it will starve for fuel when you gas it hard or go up a hill, etc.

Also you can take the hose off the carb, the fuel hose, and put in a container and it should spurt fuel out just turning over the starter. If you put the shifter between gears its like neutral you can run it without it moving. Check the pump and hoses if it does not.

Re: Motor getting too much air
 

Thanks yall. I was out hunting in very dusty conditions when this started. Still don't see leaks. Gonna pull the carb when I get home

Re: Motor getting too much air
 

Took the carb apart. It's clean. Air box tight. No leaks. Lost

Re: Motor getting too much air
 

Mixture screw was backed out

Re: Motor getting too much air
 

Did the mixture screw fix the problem?

On another thread a person was having a problem with the engine getting very hot and seemed like it was running lean. That person changed the ignitor and that fixed it. Maybe you have a similar problem.

Re: Motor getting too much air
 

Yes it mainly fixed it. It's still lacking just a touch in what power it had. Not a huge deal but do like to have as much power as I can get. It still seams to get a bump in power with choke being pulled

Re: Motor getting too much air
 

I think sometimes when the ignitor fails it does not retard the timing at low rpm like it is supposed to, and that makes it run hot.

You can drill or file the jet out really easily, but I would go by your plug reading. Small engines like to be a little rich to make the most power the plug should be tan to brown, not black not white, after a hard run WOT and quick shut down. That said most power gains are in the clutches and belt for these carts.