300 promax fuel pump

[Dean Dorsey]

The Promax 300 is a new animal to me. I believe my 1999 fuel injected version is regulated to 36lbs. I dont trust the plastic incased stock version that I currently run with mine, it makes alot of weird noise and is seemingly is cracked, worse it looks like the ones that I used to run on my old Jonny V-8s. Is there any reason why I could not run one of the large Boshe ones I have that I run with my modified 260 with this 300. Thanks, Dean

[HP]

I'd like to hear from some of you guy's about this myself! My 1999/300PM/21' Liberator runs like a scalded dog off the boat ramp. After a couple miles it seems to loose that to mid to top-end punch. I'm thinking maybe a possible fuel pressure regulator? I'd like to hear from some of you GURU's... Fuel pressure is a must with injected motors,I know this. Some of my friends that drag race cars have hot wired there fuel pump with a switch to supply maximum voltage at a flick of a switch. Can this work on an outboard?...Thanks for any input......Hal:cool:

[topkick]

http://forums.screamandfly.com/forums/showthread.php?t=63921 :)

but you should get rid of the oil injection

[Simon]

I have not had a problem making plenty of hp's with the stock setup. All of the filters need to be clean.If you have a water separator in the boat get rid of it.There is a water separator filter on the motor, after that there is another at the bottom of the high pressure pump, then there are screens in the injectors. The screens in the injectors plug up with the brush material from the fuel pump.

[Dean Dorsey]

I did replace the stock PM 300 pump with a large boshe from my 2.5 EFI motors. In my case the stock one was making alot of noise in the process of failing. The replacement worked fine as I suspected, as it would seem any fuel pump designed for an EFI motor would. That is that can supply a constant 36psi in the case of the 300 PM. Dean

[tj309]

I use external fuel pumps and never have had a problem except when I forget to turn them on. Its also nice not having to pump the bulb.

[slow ride]

I have triple 300's. Just rebuild the stock pump[cheap and simple]. The high pressure pump and pressure regulator must make 34/36 # of pressure for injectors. Check filter, main screen in vapor canister and injector screens. Inspect all o-rings for leakage. Stock pump is like a waterfall and will supply plenty of fuel to the canister as long as nothing is blocked or leaking in the supply to the pump.

[Tranzman]

Im thinking about tossing out the factory EFI pump because i'm going to run two 3.0L motors on a light ski boat, 1st reason is because at the moment I have to buy a pump and oil injection system and 2nd because they're all getting old now and thats going to be a weak link. I would like Eric Simon's view on this as I may get two of his engines later! One downfall is having to mix oil. Any one be able to tell me what fuel pumps, pressures and aftermarket fuel regulators to run?