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Old 06-08-2014, 01:26 AM   #21
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Two of four barrels of Webber carb are not opening when at full throttle (engine off when testing). Is this normal?
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Old 06-08-2014, 03:31 AM   #22
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I know nothing of Webber carbs.....but in general, a lot if 4 bbl carbs won't open the secondary's until it is under load. They use vacuum as the key to tell them to open.

That being said, they won't open unless the engine is running.
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Old 06-08-2014, 06:12 PM   #23
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I removed the carb and the two other barely open right up. The bi-metelac spring choke was holding down the shutter about half way. There is a mechanism that will not allow the second barely to open when choked.

I tested the bi-metalic spring with hot water and it worked. If I can adjust the linkage than I will, otherwise I need a new spring... attached is what was in the float bowl.

I must have been running on half a carb this whole time...

20140608_134304.jpg
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Old 06-08-2014, 06:15 PM   #24
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*not barely, meant barells. On phone...
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Old 06-09-2014, 01:31 AM   #25
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A 4 bbl carb runs on only 2 bbls until either greater than half throttle or vacuum is reached. I think it is working fine but the choke may not be adjusted properly. When cold the choke should close most of the way when the engine has warmed up the choke should be fully open.
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Old 06-09-2014, 04:39 PM   #26
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Quote:
Originally Posted by mmwjr View Post
A 4 bbl carb runs on only 2 bbls until either greater than half throttle or vacuum is reached. I think it is working fine but the choke may not be adjusted properly. When cold the choke should close most of the way when the engine has warmed up the choke should be fully open.
Yeah, the spring in the choke is bad. It reacts to temp, but it's warm position is too low. Causing the butterfly to stay over half way closed at all times.

Would that cause the fuel in the float bowl to look like varnish? When I dumped out the carb, I got two very different color fuels out of it (clean and clear & brown).

I have heard of people wiring in a switch to the fuel pump to "prime the system" should I consider this? How else could I get fuel up to the carb when starting after sitting for a while?

I am so tired of this..................................
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Old 06-09-2014, 06:48 PM   #27
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The bi-metal choke spring does lose it's tension after a while from constant heating/cooling cycles. Replace the spring.

On the carbs I know of the choke mechanism locks out the secondary side of the carb if the choke is "on". Basically, it is a preventative measure to keep a cold engine from having raw, un-atomized gas dumped into the cylinders. If the choke is not opening all the way it's likely the secondary barrels are simply not opening at all, which would definitely explain why the fuel that came out of the rear fuel bowl was skanky.

If everything is working right the carb should hold enough fuel to start the engine even if it hasn't been started for a week.
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Old 06-09-2014, 09:56 PM   #28
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+1 what ss said, however after sitting for a week I have to crank for a few seconds to refill my carb's bowl. Once warmed up restarting is just turn key.
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Old 06-10-2014, 09:16 PM   #29
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Well, it looks like another sea trial is going to be needed after the bi-metal choke spring replacement.
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Old 06-11-2014, 01:51 PM   #30
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Remember, though, it's not just replacing the spring. Once installed you need to adjust the choke when the engine is cold.

Judging rom the spooge you dumped out of the rear fuel bowl you might also consider giving that carb a good cleaning.
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