Banks

I have a 79 460 eliminator jet boat. I am the second generation owner of the boat. I have noticed a loss of about 3000 rpm. I put in a new mallory ignition, edlebrook preformer rpm manifold, a velocity stack, had the 600cc holley carburetor rebuilt, and had the motor taking out cleaned painted and put back together. The boat runs excellent. I just have not noticed an increase in rpms? Any suggestions? I am running the boat at Idle at 150 put when my foot is in it it cools to 110. I have some holes in the headers and when its running the headers have running at idle has a small stream of water coming out of the headers. I am also using an electric fuel pump.

Paul Kane

Do you mean to say that you have lost 3000 rpm or that the boat does not rev past 3000 rpm? Not sure what you are asking. How does the boat/engine perform now and what would you like it to do?

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Banks

This boat floored would reach 4000 rpm. Now it will barely reach 3600. I wanted to at least regain lost power. I would also, like suggestions on what I could do to get more power without dropping a ton of cash.

Eventually I want this to be a seventy 75 to 80 mph boat. Right now its only going about 50 mph. I know the headers need to be fixed, but can they take that much horse power out of the boat? I also just bought a 750cc holley.

Paul Kane

You stated the you installed a new Mallory ingnition. I think you you need to check your ignition timing. Make sure the advance system is functioning. Then, I would suggest you start at about 32* BTDC @ 3000 (32 degrees before top dead center while the engine is turning 3000 rpm). It will be important to do spark plug readings and check air/fuel mixture, especially since you have a new carburetor. If color is good, bump up to 34* BTDC @ 3000 rpm. These settings assume 91 octane pump gas.

However, if the plug color shows that your air/fuel is already too lean, then you will need to increase fuel to the engine before you increase ignition timing.

The tubular headers are supposed to drip water. They have small holes on the underside of the individual tubes so that water does not settle there and rust the tubes after the engine is shut off and the boat is put away. They should help the engine generate a LOT more power.

Paul

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Banks

Thanks Paul. I'll take a look at it this weekend. I took a look at your companies website last night. I know I can't afford it right now, but how much would it cost to turn this into a 572. I'll never sell this boat and I would love to beat my cousins chevy and run with my uncles picklefork.

Thanks,

Josh

Paul Kane

A 572? You don't have to jump to the biggest engine out there. Bigger is not always better, a proper engine combo is what matters most.

I would need to know more about your cousin's BBC engine before planning a combo that would allow you to give him a run for his money. What I can tell you is that if he has a ZZ572 crate motor (which is why you want a 572?), then you certainly won't need 572 cubes of Ford to pass him by. :)

Paul

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Banks

Paul I fixed the timing and it helped gain about 300 rpm. I bought new plugs and was wondering what they should be gapped at. I hear anything from .042-.046 or .052-.056. I have them set at .055 right now. The plugs I pulled out were black and the plugs were gapped at .044 and it was running great. I am putting on the 750cc carb. today and a fuel pressure gauge. What should the fuel pressure be?

Also, I ask my uncle and he is running a bbc 557 with a 850cc carb. His boat just barely beat my cousins. My uncle is H20MOFO on preformance boats.

Paul Kane

Glad to hear the timing adjustment brought back your 300 rpm. That was easy.

The plug gap for the OEM engine is around 040-045, off the top of my head, so that fact that you found the current plugs to be a .044" makes sense. 055" sounds like too much.

The 750 cfm carb will help over the 600, but since you are changing carburetors you should do more plug reading with the carburetor change, as the newly added carb may require jetting to suit your engine. Hopefully it is a Holley carb and not en edelbrock carburetor, as those seem to just be way too lean for 460's running 5000 rpm in jet boats.

The mechanical fuel pumps usually put out 4-6 psi. 6-7 psi of the aftermarket pumps would be nice...the boat can operate at 4-6 psi but if you see fuel pressure dropping to 4 psi (or less) at wide open throttle then you should refrain from long sustained full throttle passes until more fuel pressure can be maintained during those long runs.

Paul

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Banks

Hey Paul,
I re-gapped the plugs and it fired right up. I noticed a major difference right away. It is a holley carb. by the way. We did notice that when the fuel pressure was really low. At idle it is at 3 and when I step on it, it goes to 0. So my question is what electric fuel pump should i use? Electric, electric w/regulator, marine, street. And what do I want the fuel pressure to be at idle and when i have my foot on the throttle?

Thanks,

Banks

Paul Kane

Banks,

First, check that the fuel pressure gauge is reading accurately. If so, then try a bigger mechanical fuel pump, such as a Carter or Holley 150 GPH. I think that 5-7 psi, or 6-8 psi should keep the carb on your engine fed plenty.

Paul

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