Hi folks,

Well, a while ago I was riding and the piston blew apart and wrecked the case, so I rebuilt the entire engine. I sent the bottom end out and did the rest myself. Before the engine blew it was down on power and it started to miss and backfire when I really got on the throttle. Now, since the rebuild, it seems to almost do the same thing. It starts easy and idles, but when I get past, say, half throttle it starts to cut out and backfire. It also seems to want to stall sometimes, but stays running because the tires are driving the engine. That's the sound it makes, anyway.

When I rebuilt it I never attached the throttle cable to the oil injector box. I'll just mix the gas. I did no other modification like a block-off plate or anything; just didn't hook up the cable. I don't know if that makes any difference, but I figured I'd let you know.

Any tips?
Thanks

 

Sounds like you have a plugged main jet.I would hook the oil injector back up and set it.

 

A question I have is did you just not hook up the cable on the oil pump, or did you also plug the oil hose from the pump. If you didn't plug this hose and you still have oil in the tank, you will still be getting oil to the engine. Remember just unhooking the cable still gives you the same amount of oil as if the engine were idling, plus your mixing the fuel. But I would hook the oil pump back up, these pumps seldom go bad.

 

I just left the cable to the oil pump unhooked. There isn't any oil in the tank, though, because I drained it.

It's actually my dad's 4 wheeler, and he was mixing the gas for a while with the oil tank empty. Someone told him if the pump fails the engine is gone, so he just decided to mix it. The pump was attached and pumping "dry" the whole time, so that's why I left it unhooked. I'm worried that running dry for so long could have damaged it and I don't want to risk the new engine.

I haven't had a chance to check the jets yet. About all I know how to do is clean them out. When it comes to adjusting and setting I'm over my head. I will try to clean everything out and test her out. If cleaning it doesn't solve the problem, what are some other culprits?

Thanks again, guys.