8 HP Briggs and Stratton problems with surging and almost dieing

[Boudreaux In Eunice La.]

Something looks funny about that. Hope it's not bent. Anyway you might as at well do this............

https://youtu.be/0w2BRxAiUKw

You just need to lap them sometimes instead of grinding them on a machine.

 

[cpurvis]

With the each valve completely 'down', push on the valve head with your thumb and rotate. If the valve will rotate easily, it isn't seated. Seated valves are difficult to rotate.

How much valve clearance do you have?

 

[Vortec325]

Didn't look bent , I've lapped it till I have only .006 of lash . I tried pushing on it with my thumb and turning but it didn't turn . Maybe it is bent ? Guess I can take it back out and look closer

 

[cpurvis]

No, re-read my post. NOT being able to turn the valve with your thumb is good. Having .006" of lash is good, too.

Rotate the engine until the valve is off its seat and do the thumb test again. You'll see what I mean.

 

[Vortec325]

Yah I know what you meant , must have worded my reply messed up . What I was trying to say is that it passed the test but still looks wired like what BOU said . I was thinking it could be bent and still not rotate ? Doesn't look bent tho . Before I lapped it I had like .022 of lash, so maybe just that causing my surging issues . Thanks for the replies fellas ??

 

[Vortec325]

I should add that the valve guide on the exhaust side is a little worn out not terrible . Still "pops" when you put you finger over it and pull the valve out . But deffinatley not as tight as it should be

 

[cpurvis]

Yah I know what you meant , must have worded my reply messed up . What I was trying to say is that it passed the test but still looks wired like what BOU said . I was thinking it could be bent and still not rotate ? Doesn't look bent tho . Before I lapped it I had like .022 of lash, so maybe just that causing my surging issues . Thanks for the replies fellas 

It's the friction of the valve face against the seat that prevents the valve from turning.

I've never heard of engine surging being caused by valve problems. But since that was the way you chose to go, I thought I'd play along. I'll be really surprised if this fixes the surging.

But, I've been wrong before and will be wrong again.

 

[Vortec325]

Haha you don't learn from being right . Well I've checked every thing else . Started out checking for intake leaks and found nothing . Cleaned the carb multiple times . Kept doing it . Pulled the plug hoping it was lean but it was black and oily and had deposits on it . So that lead me to think it wasn't running lead and was burning some oil . Then from some advice that you can see in previous posts that it was advised to look at the possibility that the valves were messed up . I'm up for any suggestions tho

 

[Boudreaux In Eunice La.]

I should add that the valve guide on the exhaust side is a little worn out not terrible . Still "pops" when you put you finger over it and pull the valve out . But deffinatley not as tight as it should be

What do you mean by it pops ?? Sorry I had to go to the radio station and do a show from 6 to 10. My wife Missy cooked a chicken stew....

 

[Vortec325]

Put my finger over the valve guide , pulled the valve out and it made like a suction "pop" indicating that the clearances are somewhat tight because it could still make a vacume when pullling the valve out