I have a 462 and it is not running right. The engine seems to run fine anytime but idle. But when I first give it gas when I am stopped it is almost impossible to get it to move without it cutting off. I'll give it gas and it will just want to choke down. If I am going down the road and I punch the gas, it will hesitate before it kicks in.

Two cylinders aren't firing when the engine is idling, and they are the two cylinders that are connected between the cross on the intake manifold. So I am assuming that it is a vacuum leak and I am losing vacuum on both cylinders.

I have rebuilt the carburator, replaced intake manifold gaskets (twice), sealed off all vacuum hoses from the intake or carburator and that didn't help, changed the spark advance, checked the intake manifold for cracks, the engine has good compression.

The only thing that I have not tried is that someone told me that he thought that it was a worn valve guide and that is where I was sucking air from. I really hate to check that because I would have to pull the head and I dont know which head that it isbecause I have cylinders missing on both heads. Is there a way that I could chech that?

What do yall think, have yall ever heard of worn valve guides causing problems like that? Any other ideas what it could be?

 

Here's a couple of tips,

You need to be sure that your accelerator pump is working properly. Pop off your air cleaner and look down the throat. Work the throttle back and forth. There should be big healthy squirts dowm both barrels.

Also if you suspect a vacuum leak that is hard to trace try the smoke method by pumping smoke into your intake, any leak will soon show up. You can also try shop air, and look for where the air is escaping from.

If you valve guides are worn out your engine should be using a lot of oil as your engine will be sucking it up from the valve cover area.

Nick from the frozen north
1974 F-250 4X4
soon to be 429
dana 60 front and rear