Carb Question

[hpdog259962]

I have a vacuum secondary carburetor that bogs when the secondaries come in. What will cause this?

Topic

[montefrazer]

Usually caued by too much gas for the engine to use so it gets mildly flooded. As the engine revs up, the extra air flow clears the engine and things get back to normal. Look for black exhaust as the engine starts to rev up and clear out excess gas. A converter may burn the extra gas if it in’t too overly rich. It may also be caused by not enough gas and a lean air/fuel mixture getting to the engine. This may even lead to backfire through the carb. Too rich caused by too big a carb for the engine or secondaries opening at the wrong time. May even be a bad thermostat not letting the engine warm up enough. Too lean caused by bad accelerater pump, not enough gas in the carb (wrong float level, pugged filters, weak fuel pump, bad gas line), vacuum leak, poor tune up, weak coil, distrubuter(vacuum advance, timing, dwell, worn out), or even early 70’s emission sytems that controled spark advance. If this is a computer controled carb, it may be a sensor problem. Is this the factory carb or a replacement?

[hpdog259962]

Replacement (Holley)

[montefrazer]

Holley’s are very tuneable. I would suggest picking up a book on them as almost every piece on one can be changed. You still need to know if the carb is too big for the engine. I had a 650 spreadbore Holley on a mildy built 350 Chevy and that was almost too much carb for it. It was manual secondaries and I had to watch my RPM before I could floor it or the engine would bog down.

[hpdog259962]

OK, Thanks Montefrazer!! thumbsup.gif

[Author]

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