Something changed

[jcatnite]

Something changed on the weber. It will run when it is cold but once it heats up and the choke cuts off, I can't give it much throttle. If you do it fluttes and dies. I managed to get it started by holding my hand over the top of the carb and limiting the air with my wife starting it but she couldn't keep it running. Then she promptly turned the ignition key past the start contact and now it doesn't work at all...lol. Guess I'm in for a new ignition switch and steering lock. Wish I would have bought one before they went to 200 bucks apiece.
She was trying to help.
What do you think about the weber? I'm suspicious of the power valve but maybe its a stopped up jet? I just had them out and verified they were open.
JC

 

[tosoutherncars]

JC, if you can start it with your hand mostly blocking the intake, that certainly suggests a vacuum leak is leaning it out, no?

 

[jcatnite]

I would think so. Or could it be that the mixture is extremely lean?

 

[texas_bugeye]

Sounds like crud in a jet.

 

[DrEntropy]

Jet crud wouldn't allow it to go rich (run well when "cold") then fall on its face after warming to temp. Rich condition at all temps is morelike what is causing the prob. Leaking needle valve at float (~could be~ crud THERE), a too high pump pressure, or a jet not seated well. Or just plain too-rich idle jet.

 

[texas_bugeye]

Thats true my bad. your right about the float seat needle could be crud there.

 

[jcatnite]

Well, I have to report, that I'm not sure what it was. I pulled every jet out of the carb (one at a time) and flushed jet and passage with carb cleaner. I lowered the float height quite a bit based on a Weber rep's recommendation. I found a suspect loose (-) post on the fireball coil (tried to tighten it and promptly rung it off) so switched back to an older balasted coil that I've had for a while. Repiped the fuel inlet to the actual inlet instead of the return line for the bowl (they go to the same place but the return line has a looks like 0.015" orifice in it. Found the backfire had knocked timing down to about 9 BTC? I'll blame the backfire probably me when I tightend the dizzy back down. I remember verifying it but anyway, reset it back to 12 BTC per Jeff's instructions. Hotwired the ignition switch and she started right up. Your guess is as good as mine. I think the float level was just way too high. I can't drive her yet as the steering column is still loose from the ignition key incident but she ran and idled great sittin in the sun in the driveway.
JC