79 k20 400 running rough, can't figure it out.

[Bextreme04]

10 seconds of cranking got me 6 ounces, I don't know if it matters but I think it may need a battery, cranking seems a little slow on a full charge.

That's a bit low. You might have junk in the tank clogging up your pickup screen or maybe a worn fuel pump eccentric on the cam that isn't giving a full fuel pump stroke.

I'm still leaning towards the carb needing lots of adjustments or having something wrong with it though. The fact it needs all that pumping and priming to get it to start says something isn't right.

 

[Ricko1966]

Are the vacuum advance and the centrifugal advance both functional? Does the choke plate close for cold starts? Carbs been rebuilt twice. I'd eliminate everything I could think of besides the carbureator before assuming that's the problem. Blamed it once,had it rebuilt,blamed it again had it rebuilt blaming it for a 3rd time,not saying it's not possible,but I'd check EVERYTHING! else including intake leaks very thoroughly before I blamed the carbureator again. I'd also take it back where they built the carb,show them,ask them.

 

[yellowdog5]

There is a fairly big squarebody group there in Eugene that I'm a part of and they do meets throughout the year. I drive my K25 down for the meets a few times a year and there are also some really knowledgeable folks that live in that area and could help you out. If you aren't already a member, I suggest getting involved in the Eugene/Springfield Square Bodies group on facebook(or whatever it's called now).

Bextreme 04 thanks to your suggestion I found a local guy who came out and checked it all out, air leaks is a lot of the problem, he's going to adjust valves and replace gaskets, he thinks that will fix it. I really feel like he knows what he's doing, which is a LOT more than I can say for others I have tried.

 

[Bextreme04]

Bextreme 04 thanks to your suggestion I found a local guy who came out and checked it all out, air leaks is a lot of the problem, he's going to adjust valves and replace gaskets, he thinks that will fix it. I really feel like he knows what he's doing, which is a LOT more than I can say for others I have tried.

That's great! I saw you post in the group the other day and was glad someone was able to come look at it. I'll PM you my info on the group so you have it in case they can't get it going or you need some more help on it. I know a few people down that way that are pretty good with the squares and I also drive down that way sometimes myself.

Hopefully we get to see you at some of the meetups in Eugene with a fully tuned up and great running truck this summer!