about two months ago I put a new overflow valve in because truck had a bad miss between 1000 and 1250 rpm. Needles to say after I put it in I noticed it started a lot faster and the miss was gone. Within a week or two the miss was back, but not all the time. It only seemed to come around once every couple days. Then more and more, now its there all the time. My question is, I read in a couple of threads that the free lenght of the spring is somewhere around .550. So I pulled mine out and it measures .760. Is this something I should be concerned with or am I just paranoid.

 

Nobody's even got and opinion.

 

Length of spring should be .5 inch. If it has changed a reset of length will work for awhile but new is the way to go. Keep old for emergency use only. Once a spring loses it's strength it never comes back and will get weaker with time.

 

How do you reset a spring that is too long without cutting it. If I did that it wouldn't have a flat seat on teh bottom for the ball to rest on. I dont think I should have to cut it, I mean how does a spring that is always under tension get to be .200" longer then spec.

 

The .55 is for a valve set for 22-25psi
.76 is for a 25-28psi valve
Both pressures will work just fine.
I don't recommend that anyone plays with the spring unless you have a FP gauge to see what you've done.

Your problem sounds more like an injection pump delivery valve sticking. Try a heavy dose of fuel additive that cleans and lubes and see if that clears it up.

 

Or move the suspect dilivery valve and see if miss follows the delivery valve