Topic: Jetting for a Holley 94


Sneezer    -- 08-27-2018 @ 6:18 PM
  Looking for advice on the appropriate jetting for a
Holley 94 carburetor that I am installing on a 1952 Mercury motor in my 1935 Ford couple. Jets I removed are 51s. Throats are 1.25 inch. Thanks: Arnie


TomO    -- 08-28-2018 @ 7:17 AM
  The 51 main jets should work OK in most areas of the country, but I would check the plugs for a lean or rich condition after driving the car for 30 minutes or more and shutting the engine off without idling for more than minute. The power valve will also affect the mixture.

What year and type of vehicle does the carburetor come from? The flathead carbs all had a .94 venturi, the carb that you have sounds like it may have a larger venturi. The size of the venturi is usually cast into the main body of the carburetor.

Another consideration is the camshaft. Is yours stock?

You will also need to find the best power valve for your configuration. A rough guess can be made by looking at the exhaust when you open the throttle quickly. If black smoke comes out, you need a power valve that opens with a lower vacuum. If the exhaust looks normal, then drive the car and see if it pings on acceleration. If it does and timing is correct, you need a power valve that opens at a higher vacuum.

Tom

This message was edited by TomO on 8-28-18 @ 7:48 AM


Sneezer    -- 08-28-2018 @ 5:49 PM
  Thanks TOMO for the reply to my question. The wealth of information you provided is appreciated. I have no background on what the carburetor was installed on. Ebay was the supplier . I simply gave it a dipping in carburetor cleaner and installed an overhaul kit. Installation will be accomplished tomorrow. I will report on the results in a couple of days.

My motor was purchased used with a recent overhaul. Camshaft is stock. Motor actually runs well except for roughness when just applying a little throttle. Thought I would try a different carburetor to see if I could eliminate the problem. Will see. Regards: Arnie


TomO    -- 08-29-2018 @ 7:58 AM
  Post a photo of the carb, we may be able to identify it and the application.

Roughness with a little throttle could be due to the incorrect power valve.

Tom


Sneezer    -- 09-07-2018 @ 8:59 AM
  Problem solved. One emulsion was plugged with debris. Replaced it and motor now runs great. No roughness at idle. Thanks for the help. Arnie


Sneezer    -- 09-07-2018 @ 9:00 AM
  Problem solved. One emulsion was plugged with debris. Replaced it and motor now runs great. No roughness at idle. Thanks for the help. Arnie


Peder D    -- 07-03-2019 @ 4:49 AM
  TomO writes: Roughness with a little throttle could be due to the incorrect power valve...hmm...could this be the problem with my 46 Merc?


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