My 86 w150 with a 318 will run good at idle, but when you give it gas it stumbles almost like it is missing. But if you ease on the gas it will run good. And under a load it will fall on it's face. Any ideas? Thanks

 

Check the timing? Check for vacuum leaks, etc. If those things are ok possible carb problems.

 

Do think it is carb trouble I have all ready rebuilt it. I have two vacuum lines that go from the vacuum bulb by the transfer case up to the engine some where. I have not seen the lines in any diagrams for vacuum. I think I may have a couple for broken value springs on number 5 or 7. But it idles good with no load. The timing is set at 8° before tdc. I'm at a stand still now. Thanks

 

is your carb float adjusted properly... also might as well tear the top half of off and check the jets, mine did the exact same thing! like literally if you gave it any gas above idle it would fall on its face unless the choke was on.... my jets were clogged and there was a load of dirt in the float bowl

 

I soaked and cleaned the carb. It was all clean when I put it back together. I will check it today. And if it makes any difference my 86 has the scc on it.

 

Did the carb again and still is falling on it's face. I can't get the timing to set. Maybe needs a new timing chain or valve springs? This has me puzzled.

 

Perform a timing chain deflection test to see how worn out the timing chain set is.

 

How do I do that? The timing chain test , that is.

 

Any ideas?

 

or just get a timing light and see what its set at to begin with, and also check ALL your vacuum lines... twice