So my nearly 3 year old Holley 4160 has a vacuum leak on the driver side where the secondary shaft passes through the base. Outside of a p.i.a. rebuild to the base, does anyone have a fix? Outside of that I am looking at a new carb. Anyone familiar with these? https://www.holley.com/products/fuel_systems/carburetors/brawler/diecast/parts/BR-67253
If the throttle shaft is where it's leaking, then at least a partial rebuild is necessary. Is it also leaking fuel from there? If so, a throttle shaft bushing would have to be installed.
At the moment it is only a vacuum leak, no fuel. Summit offers Holley carb base replacements, but honestly I would rather replace it than try to repair. Summit has a carb that I was told is based off an older Ford design. I have seen numerous positive reviews on multiple sites about it and it is less than the previous carb I posted above. https://www.summitracing.com/parts/sum-m08600vs
A three year old carb that needs a base plate costing roughly $115... http://www.jegs.com/i/Holley/510/11...PoQ2Po80lsRVVColl2tOhOGOAMZHKlklXgRoCNiXw_wcB Would be a no brainer for me...
Are you certain it's the base and not the gasket? I would be with Krazy and just replace the base if the carb is overall performing well. - Matt
My 4160 has developed a slight hesitation. What is yours doing? How did you determine where the vacuum leak was coming from?
The Summit carburetor is a great buy. I ran one for several years and highly recommend it should you decide to replace rather than repair.
Slight hesitation is rarely caused by a vac leak... Generally misadjusted pump shot linkage or maybe a hardened pump diaphragm is the culprit... Late ignition timing can also cause a issue...
You can get a hesitation problem with a vacuum leak. In my particular case it became increasingly more difficult for the car to hold a steady idle, hard starting, choppy idle in gear, will not idle in gear, extreme hesitation on acceleration. In the past I knew this engine had a manifold vacuum of about 20lbs. Once the symptoms appeared, manifold vacuum was between 10 - 15. To find the potential source of the leak, I disconnected and plugged all vacuum connections to the manifold and carb. While the engine is running I sprayed carb cleaner around the manifold and carburetor. It will be obvious when you hit the right spot as the engine will slightly rev up. In my case, part of the leak was from the secondary throttle shaft (it is a 4 barrel carb). After replacing the base plate it no longer leaks through the throttle shaft but there was still a leak. So I replaced the carb with the Summit one listed above and put the Holley on the shelf for a later rebuild.
Thanks Hotrock, you were right it is a great buy and so far runs great. Throttle response is awesome right out of the box.
Good tips. Sounds like my problem may be the diaphragm. Ran fine last fall but problem developed over the winter.
A bad vacuum advance cannister on the distributor can cause a part-throttle hesitation. Make sure yours doesn't have a bad diaphragm.
O.K. Already bought the diaphragm for the Holley so I will try that first. The car still has the original distributor so it is possible the vacuum advance could need replaced also.
