help tuning my CA77 carb AKA Fuel delivery issue?

[Hahnda]

Yes, I would leave those jets out. They are the incorrect size. If I also remember correct the float valve is also of a different size. It works if you replace the needle and seat but if you put the new needle in the old seat its a no go. I might be off that that though.

[teazer]

Thomas,

You appear to be on the right track based on the information so far. Typically if the motor runs better with the choke on, it tends to indicate a lean mixture.

That might typically be from a partially clogged fuel tap or feed, but in your case is more likely to be;

Low fuel level (floats too "high" when measured upside down.
Partially clogged main jet
Blockages in the emulsion tube or air jet
OR a bowed flange where the carb bolts to the head.

It is very easy to over tighten the carb nuts and bow the flange. I would check the flange and the tufnol insulating spacer.

[teufelziege]

I got all of that and I think it'll be a good place to start. The only thing I wasn't sure about is the flange and "tufnol insulating spacer". The flange I think I get. I didn't tighten the bolts too tight, but how do I know if it's bowed? And that spacer? huh? The gasket?

Thomas

Thomas,

You appear to be on the right track based on the information so far. Typically if the motor runs better with the choke on, it tends to indicate a lean mixture.

That might typically be from a partially clogged fuel tap or feed, but in your case is more likely to be;

Low fuel level (floats too "high" when measured upside down.
Partially clogged main jet
Blockages in the emulsion tube or air jet
OR a bowed flange where the carb bolts to the head.

It is very easy to over tighten the carb nuts and bow the flange. I would check the flange and the tufnol insulating spacer.

[rustywrench]

TZ,
Search 'AIR LEAK" and read volumes about the flanges and spacer blocks. One good way to tell if ya have an air leak is to get 'er good and warm then spray carb cleaner on the spacer. If you get a change in RPM ya got a leak. The old O rings get hard and flat over the years and don't seal properly sometimes. RW

[teufelziege]

Ah, part of the problem might be that I don't seem to have a spacer. My carb is sitting right up against the intake manifold. It does have the small rubber gasket on the head side of the carb, but I believe it's mated directly to the head without a spacer. Well, there's one thing I gotta correct.

Thanks!

TZ,
Search 'AIR LEAK" and read volumes about the flanges and spacer blocks. One good way to tell if ya have an air leak is to get 'er good and warm then spray carb cleaner on the spacer. If you get a change in RPM ya got a leak. The old O rings get hard and flat over the years and don't seal properly sometimes. RW

[LOUD MOUSE]

Where ya located?. .......lm

Ah, part of the problem might be that I don't seem to have a spacer. My carb is sitting right up against the intake manifold. It does have the small rubber gasket on the head side of the carb, but I believe it's mated directly to the head without a spacer. Well, there's one thing I gotta correct.

Thanks!

TZ,
Search 'AIR LEAK" and read volumes about the flanges and spacer blocks. One good way to tell if ya have an air leak is to get 'er good and warm then spray carb cleaner on the spacer. If you get a change in RPM ya got a leak. The old O rings get hard and flat over the years and don't seal properly sometimes. RW

[teufelziege]

Im in sacramento, CA

Mmmm, I think I might know why I am missing the spacer…looks like the stud on one side is shorter than the other. It must not have fit with the spacer…..the plot thickens!


Thomas

Where ya located?. .......lm

Ah, part of the problem might be that I don't seem to have a spacer. My carb is sitting right up against the intake manifold. It does have the small rubber gasket on the head side of the carb, but I believe it's mated directly to the head without a spacer. Well, there's one thing I gotta correct.

Thanks!

TZ,
Search 'AIR LEAK" and read volumes about the flanges and spacer blocks. One good way to tell if ya have an air leak is to get 'er good and warm then spray carb cleaner on the spacer. If you get a change in RPM ya got a leak. The old O rings get hard and flat over the years and don't seal properly sometimes. RW