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Thread: 235 Johnson Fuel Pressure
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03-28-2010, 04:26 PM #15000 RPM
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235 Johnson Fuel Pressure
Guys:
At the end of last boating season, I bought a 1979 Allison GT-20 that had a 1980 Johnson 235 engine (V6 carbed). I have been cleaning it up this winter and am now working on the fuel system.
The guy that had it before me had an old Holley fuel pump (part number 34R 7446B) and a pressure regulator. I did some online searching and found out that the Holley fuel pump with that number does not exist anymore. Further, I am not sure what the correct pressure should be for this engine.
Can anyone advise what new pump to buy and what pressure to run? Do I need to get a pressure regulator also?
Thanks for any help.
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03-28-2010, 05:20 PM #2Banned
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Unless unit is highly modified and running main jets larger than 0.76 go back to stock fuel pumps. Thanks Martin
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03-28-2010, 05:24 PM #3
Fuel pressure with the stock pumps is 3-5 psi. The red Holly fuel pump is internally regulated to 7-8 psi. There is no need for a regulator with this pump. The only problem you may encounter may be flooding with the motor tucked in all the way or flooding under hard acceleration. To fix this all you have to do is lower the float level in the carbs.
If this is your first experience with a v6 cross-flow you should search this forum, there is a lot you should know about it.NRA Life Member
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11-30-2017, 10:54 AM #45000 RPM
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Good information.....
23 Elim twin omc 225's blue holley pumps with re-regulated to 4.5-5psi thanks to this descussion.
I would like to install the 2.7 heads i have, gut air box and jet up 10....
My largest main jet will be 75D, do you see any reason to up the fuel pressure with this set up ?
Thanks,
B
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11-30-2017, 07:02 PM #5Scream And Fly VIP
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Gutting the air box, installing 2.7 heads and only going up 10 sizes is looking to burn a piston. Fuel pressure does not increase what goes thru the jet.
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