fuel starvation issue solved

[al v]

For the last month or so I've been having a fuel starvation symptom that would come and go.

It would seem to happen for 20 to 30 miles per tank of gas. No rhyme or reason.

I had checked the vent tube twice already and each time it was routed nicely and was clear of obstruction.

Today I reversed the spring in the petcock to finish my earlier dan marc install.

I removed the vent line to #6 intake, which I figured would rule out the vacuum tube to the petcock and the petcock itself.

Then when putting the tank back on I saw what I think the problem was. The vent tube had developed a soft spot right where it attaches to the tank and appears to have been collasping/kinking under its own weight. This was only detectable by bending the vent line and seeing it collapse.

While I had the tank off I installed interstate springs in the carbs.

Took it out for a short ride and my laddy is very much sassy again!

Will need to run a couple hundred miles to know for sure...

[gordonv]

Had the same type of problem with my Volvo 740 Turbo (same, but on a larger scale).

Seemed whenever I tried to make a left hand turn, the engine would bog down and almost die. Would have to let off the gas and then try again but slower. Didn't seem to happen on right hand turns. The short, the turbo tubes where overly soft from oil over the years, and the engine drawing the air when you step on the throttle hard would make the tube collapes, closing the air intake to the engine. Seemed to happen on left hand turns, but not right, because you are more in a hurry and want more fuel, where right hand was more casual turns.

It's always nice to have some closure on an issue. Another reason when others talk about vacume leak to just replace the lines, as it;s hard to find those micro cracks and any soft hoses.