randymbtech

Hey guys, having a problem with my Mercruiser 330 horse 454 in my '88 241 Liberator. I installed a brand new Mercruiser big block fuel pump over the winter when I re-built the motor. It ran fine for a couple months and then started flooding over after idling for a minute or two. I re-built the carb 3 times, until I did a fuel pressure test and found the mechanical pump putting out 12 psi at idle!!! This was too much pressure for the Q-jet, and was causing it to flood over. I replaced the pump with another brand new Merc pump, and now it idles perfect, BUT the boat won't hit high RPM! It bucks like hell and is running out of fuel over 4000 RPM. I did another test and found only 3-4 psi from this pump...AGGGHHH!!!

My question is, is there a better mechanical pump that i can buy that will actually put out the 6-7 psi that I need??? Thanks!

ROTAX454

Once having those motors in my boat, I am familar with those mechanical fuel pumps on the raw water pump. Suggest you upgrade to these:
http://www.keitheickert.com/p-12460-...6-engines.aspx

Don't forget to clean out the lube bath and refill with the correct lubrication.

randymbtech

My fuel pump bolts to the block, not to the raw water pump housing, but thanks for the link! Mine is a big block Alpha, and has the raw water pump in the drive, should have stated that!

randymbtech

Thats a great site, thanks for the link. Thinking about purchasing this one:

http://www.keitheickert.com/p-14089-...-chevy-v8.aspx

picklenjim

That's the one you want. You can also get those from Jeg's or Summit. Probably a little cheaper.

randymbtech

That pump is cheaper than the Mercruiser ones I bought! I hope it's made better, these new Merc pumps are junk. I wonder why the pressures are all over the place? My boss had the same problem with his new Merc pump, to much pressure, and flooding his carb over.

firehawkcat

I just put on a Jeg's fuel pump mine runs perfect

randymbtech

Which one?

firehawkcat

Cant remember the model # boats engines require alot more fuel delivery than a car Here it is Jegs brand model# 555-15961 110gph bbc they have a 80 gph but i went with more fuel delivery running around 450hp with edelbrock 750 carb

firehawkcat

Oh yea $ 54.99 could not find a fuel pump with this gph at any store in town thats why i went to Jegs