vacuum advance troubles

[enferno]

289, 2v carb. only one port on the carb for vacuum advance, and it's getting roughly 14 inches of vacuum at idle. should i tear the carb apart and rebuilt it, hoping to solve the vacuum problem? car runs really nice, but i want to get that extra bit of fuel economy that comes with it.

thanks

 

[tos]

Whats the problem that your having? Thats not really that low. Unless you have a vacuum leak in your carb or a blocked passage rebuilding the carb wont help and if its running good I wouldnt suspect a carb problem. Low vacuum is due to worn out rings, Improper timing or a high lift cam. There are a few other things that could cause low vacuum but these are the most common. I'd start with the timing myself or you could run a line off a vacumm port on the intake itself and possibly get a little more but the one one your carb is a timed port.

 

[enferno]

Whats the problem that your having? Thats not really that low. Unless you have a vacuum leak in your carb or a blocked passage rebuilding the carb wont help and if its running good I wouldnt suspect a carb problem. Low vacuum is due to worn out rings, Improper timing or a high lift cam. There are a few other things that could cause low vacuum but these are the most common. I'd start with the timing myself or you could run a line off a vacumm port on the intake itself and possibly get a little more but the one one your carb is a timed port.

i thought i was suposed to get very little or no vacuum at idle from the timed port on the carb. if that's not the case, then i just made a stupid mistake

thanks!

 

[Max Power]

No, you not have any vacuum at all thru a timed port. If you do it is because the idle is set a bit high. Vacuum shouldn't come through that port unless the throttle blades are cracked.

 

[enferno]

No, you not have any vacuum at all thru a timed port. If you do it is because the idle is set a bit high. Vacuum shouldn't come through that port unless the throttle blades are cracked.

the blades are fine . . what else could it be?

 

[tos]

Sorry I was confused about what you wanted. I thought you were trying to get more vacuum thats why i suggested a manifold port. I know a few people who dont care for the timed port and want 18 inches at idle.

So back to one of my other suggestions. Timing. It could still be that your timing is off and someone as compensated by adjusting the idle on your carb as max power said, your throttle butterfly could be opened a bit too much to compensate for bad timing. I would start there since you said the car runs fine otherwise.

 

[Max Power]

the blades are fine . . what else could it be?

By cracked I don't mean broken. I mean cracked open, as in off idle.

What is the timing set at? What is your base rpm with vacuum disconnected?