exterior tri power leak 1967

[Roger Konkel]

I have gone through the three carbs four times now. I have replaced new gaskets with new gaskets, tightened and retightened screws, bolts and nuts. Checked bolt length for proper length and still I get a gas leak on the manifold under the float bowl on the center and rear carb. It only happens when the car sits for several hours. While running and I must say the car runs absolutley perfect there is no leak inside or out and while idling both out board carbs are dry on the inside. I noticed on the flange where the gasket butts up to on the float housing on the bottom there is a small hole that seems to vent back into the float bowl when I blow on it. What is that and should it be there?

PLEASE help me I am about to lose it

Thanks

[Rich G.]

Re: exterior tri power leak 1967

There was a post recently about this by Clem Z., I think. The poster said pressure can build when the car is shut down and the carbs can leak. If you can't find it in the archieves I'm sure someone else will chime in. By the way, my L71 does the same thing. It's been so cold here I have not been driving it, and I only had it for a few weeks before it got cold, so I'm waiting for spring to see if it still happens.

Rich Giannotti

[Clem Z.]

Re: exterior tri power leak 1967

check the bowl for having a "bow" from side to side,set it down on a flat surface and see if there is a space in the middle. i find this comes from tightening the bowl screws too tight. the only cure since you can not straighten the bowls is to use 2 gaskets or get new float bowls. the center carb leak could also come from a leaking accelerator pump cover.

[Wayne K.]

Re: exterior tri power leak 1967

Roger,

When you had things apart did you check the metering blocks to see if they were warped ? If a carb doesn't have a metering block then it would have a metering plate which should also be checked to see if it is warped. If any of these are warped I think that this could be the source of your problem.

Wayne

[Clem Z.]

Re: exterior tri power leak 1967

wayne makes a good point, check the main carb body surface where the bowl mount for flatness. this can be filed flat with a large "bastard" file. the metering body on the center carb has to be straighten in a jig using a press if it is warped. most external leaks i have found come from warped float bowls.

[William Holder]

Re: exterior tri power leak 1967

THe hole in the float housing is for the accelerator pump. It should only be present on the Center carb. If it is on the end carbs and there is no accellerator pump present it could leak there
Bill

[Wayne P.]

Re: exterior tri power leak 1967

The last ones I fixed were the main housing warped. Like to have drove me crazy or maybe crazier. Anyway I had to have it milled. It took 0.030" to get it flat. Worked great and still is. MOst of these old Hollys have bseen alot of abuse over the years.