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Just rebuilt SU's, still won't start. Ideas?


Phyte

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My car ran with the flat top carbs a couple days ago. I rebuilt the SU's that came with it and adjusted them according to a whole bunch of instructions I found online. Its getting fuel, but it just won't fire :( I thought SU's were pretty much supposed to run no matter what, it was just tuning them. The rebuild went perfect and I know I did it right on each one. I've rebuilt many a carbs before. What else could be causing this.. I'm desperate!! Its 4:15 am!!!! :cry:

 

Phyte

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Guest Nic-Rebel450CA

need more info.

 

How are you confirming that it is getting fuel?

Are the carburator pistons moving freely?

Did you adjust the butterfly for the correct amount of opening under full choke? Is the choke moving? How far out are your adjustments? The knob on the bottom should be out about 2.5 turns, and try setting the top-side adjustment screws at just 1 turn out to get started (this will make the idle speed higher so be ready to back them off if it fires up).

 

Oh ya, and can you tell if there is a vacuum leak, possibly around the throttle shaft?

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need more info.

 

How are you confirming that it is getting fuel?

Are the carburator pistons moving freely?

Did you adjust the butterfly for the correct amount of opening under full choke? Is the choke moving? How far out are your adjustments? The knob on the bottom should be out about 2.5 turns' date=' and try setting the top-side adjustment screws at just 1 turn out to get started (this will make the idle speed higher so be ready to back them off if it fires up).

 

Oh ya, and can you tell if there is a vacuum leak, possibly around the throttle shaft?[/quote']

 

1) I cleaned the carbs really good. When I try and start it and lift up the piston there is fuel at the bottom of it. Not puddled, just "wet".

 

2) I made sure that both carb pistons are moving freely and fall with a "clunk"

 

3) I didn't adjust the butterflies any. I adjusted the mixture nut at the bottom out 2.5 revs just like all the online documentation says. Tonight when I get home I'll turn down the idle screws(1 rev out) and try again.

 

Not sure if there is a vacuum leak. The carbs looked real good when I rebuilt them. I made sure and took the time to clean everything and reassemble everything exactly the way its supposed to be. I'm going to pick up some starter fluid and a match(just kidding :D).

 

I ran the battery completely down lastnight trying to get it to start :(

 

Any more ideas?

 

Phyte

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Guest Nic-Rebel450CA

Do you have a camera? I cant help but think that some piece is missing. :weird:

 

You may end up needing to take them off and check the butterfly, but when I was checking mine I couldnt really see how it could be off unless the linkage was bent.

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Do you have a camera? I cant help but think that some piece is missing. :weird:

 

You may end up needing to take them off and check the butterfly' date=' but when I was checking mine I couldnt really see how it could be off unless the linkage was bent.[/quote']

 

I called ztherapy. I have the vacuum lines off the float chamber hooked up to the "rail" on the emissions crap. This is how the flat tops were hooked up. He said just to run those to the air cleaner. Also I need to run the vacuum advance from the distributor to the front carb. I'm going to try these when I get home from work. If these ideas don't work I'll post a pic of the setup.

 

Phyte

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Guest Nic-Rebel450CA

sweet, nice work!

 

That ign wire was probably an inadvertent safety measure. :wink: I cant imagine what those carbs would have done with the vacuum lines hooked up to the wrong points.

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