Engine will only run above 4000 RPM. Carbs or timing?

[Zedyone_kenobi]

THE 4x8 sander is great, but you still need to check the flatness. Even though it was a flat sander, there is no guarantee that even pressure was applied across the intake. You should find some kind of trustworthy flat surface, and take some feeler gages to see if there is any uneven surfaces.

[grannyknot]

Okay buddy I have been thinking. I would like you to try to remove that regulator. I know you said it was putting out 1.5 liters smoothly, but that was with zero backpressure. Regulators require backpressure to work. What we do not know is how it is metering fuel with that electric pump AND that regulator. I would like you to try to run with a different regulator maybe. I am still not convinced it is not fuel related.

Zedyone, I think I might have done this test but in a different form, with the triples and the SU's I did a number of start tests with and without the fuel pump powered. The tests without any fuel pump, just using the fuel in the bowl

to start the engine were really no different than with the pump. Both the triples and SU's have a normal air pressure vent tube so there would be normal atmospheric air pressure. Wouldn't that prove the pump and regulator aren't effecting these problems? I don't mean to be argumentative just trying to eliminate possible causes.

[Captain Obvious]

So what are you currently running for ignition? What's the system look like?

[grannyknot]

So what are you currently running for ignition? What's the system look like?

1976 distributor, Pertronixs HEI ignition, Pertronixs coil, NGK wires and plugs.

[Captain Obvious]

OK, so I'm of limited use here... I know very little about the aftermarket stuff.

Where is the timing advance curve being introduced? Mechanically in the distributor, or electronically in the HEI module?

Surely not both, right?

[grannyknot]

Captain, good question. I don't think the HEI unit regulates timing advance but not 100% sure. The vacuum advance is working but I plugged it off to try and eliminate any possible vacuum leaks, that leaves the mechanical advance that I assume is working. I did disassemble, clean, lubricate and put it all back together properly.

[Captain Obvious]

I know some of the more complicated aftermarket electronic ignitions systems have programmable advance capabilities. I just didn't know if yours was one of those. I'm assuming if you don't know for sure, then it's not. Shotgun approach here... Have you got access to a stock ignition module? Is the wiring still intact enough for that?

Man... Just so many variables. If you bring the car to my place, I promise in a weekend we'll have it licked!!

[Reverend]

Have you consulted Ted? At least he looks like he has something to do with this problem. Maybe you have not feed him well enough? Cats can be vicious when hungry

[Wade Nelson]

I've never seen a more worthless thread than this one.

It only takes 3 things to make an engine run. A combustible air/fuel mixture, compression, and correctly timed spark.

Yet after over 128 posts it has STILL not been determined which of these three items is lacking resulting in this motor not running properly below 4K.

Someone needs to get back to basics.

[Zedyone_kenobi]

Peace wade, but this could be a combination of the three, or an intermitent or rpm dependent failure. Also, he is obviously working along, and that can give you challenges all by itself. Sometimes just having 2 more hands to help you can do many more simultaneous 'fixes', and try more things.

What we need here is a spreadsheet, with everything that has been tried and how it was tried. We can figure this out.

[bartsscooterservice]

I've never seen a more worthless thread than this one.

It only takes 3 things to make an engine run. A combustible air/fuel mixture, compression, and correctly timed spark.

Yet after over 128 posts it has STILL not been determined which of these three items is lacking resulting in this motor not running properly below 4K.

Someone needs to get back to basics.

Exactly.

-> Timing seems okay, and he has a spark

-> Compression seems okay

fuel issue left...

( he's reporting wet spark plugs and fuel dripping out of carbs )

[grannyknot]

Well I'm terribly sorry that this thread is not as rewarding an experience as you had hoped for Wade, I can just imagine how frustrating it must be for you.

If you would bother to read those posts you would see that the basics is all I have been dealing with for almost 2 months.

Keep your whining to yourself.