390 Holley on a flathead

nellis003

nellis003

Senior Member
Hey all,

Just fired the 51 Merc for the first time today! She only runs for a few seconds before sputtering out, but it's nice to hear her go.

Does anyone have any setup tips for a Holley 390 on these engines? I bought this one used and just bolted it on; it came off a running Jeep. Seems now like it's not giving enough gas to the engine.

Also, not sure how to hook up the electric choke. Is it just power from ignition?

Thanks,
Nick
 
The automatic choke just hooks to the ign. switch (you can fuse it if you want to). The 390 I have on mine (purchased new) ran perfecly right out of the box. Am assuming that you already have a 4bbl manifold with adapter plate in order to bolt it right on.:confused:

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I jetted mine with 50 or 51's?? I think either one is OK. I run an electric choke but wouldn't mind a manual. I changed the throttle hook up for my application.
 

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What is the number on the airhorn? There were two 390 cfm carbs with different metering. Also no telling what some previous owner did. I would never bolt on a carb without first looking at the innards.
 
Mine also cranked and ran 'out of the box'. Should be getting plenty of fuel. Have you checked the float settings?


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This may be a silly question, but are you using an original flathead fuel pump? They are only regulated to give about 2-2 1/2 pounds pressure. The Holley needs about 7 pounds to fill the float bowl properly. Good luck!
 
nellis003 said:
Hey all,

Just fired the 51 Merc for the first time today! She only runs for a few seconds before sputtering out, but it's nice to hear her go.

Does anyone have any setup tips for a Holley 390 on these engines? I bought this one used and just bolted it on; it came off a running Jeep. Seems now like it's not giving enough gas to the engine.

Also, not sure how to hook up the electric choke. Is it just power from ignition?

With a 10amp fuse or breaker
Click to expand...
 
The original Load a matic distributor wont work with with this setup. I know this doesn't answer your question, but it is an issue you'll have to address in the future
 
KiWinUS, thank you. It's not really 'Forum friendly' here (although some hear know it from another flathead site as the 'Goofy Jeep' project) and I'd like to stay in good company here we'll just do it this way.....I think this link ought to take you to a writeup explaining what it is and why and some more pics....it does have much early Ford influence.....

Let me know if the link doesn't work and I'll send you to another spot...Thanks again!

http://www.whatareyouworkinon.com/content/1947-willys-cj2a-rpu
 
rocnroll , that is too awesome , thats 1 hell of a nice "Hot Rod" an absolute credit to you !!!
Thanks
Cheers
Tony
 
Did you remove the 2 site plugs and start it up and set the float level to the bottom of the site plug holes?
 
cbillelder said:
This may be a silly question, but are you using an original flathead fuel pump? They are only regulated to give about 2-2 1/2 pounds pressure. The Holley needs about 7 pounds to fill the float bowl properly. Good luck!
Click to expand...

Running an original fuel pump. It provides adequate volume of fuel to keep the bowls full.
 
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That port does not give the proper signal to the distributor. It is the same as manifold vacuum, except it is closed off at idle.
 
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