540 Bbc Fuel Pump
 

I have a Gen V 500hp stroked to a 540 with merlin III heads, msd, 741 cam 1.8 isky rockers, dart intake ,cmi, running the raw water pump with the stock fuel pump with bigger ss lines and a aero fuel pressure reg to a holley 4150 1000hp cfm carb with a spacer. Could my fuel pump at wot not provide the gph? Does any one know the gph of the stock merc 861677t ? I still have some throttle left but no additional power after 5000+ rpms. rev limiter is at 5800, went up and down with jetting + prop sizes and did not change much.

i have the same issue.my advice would be not to run it until u change the pump.im looking into putting an electric pump on mine...dont think they make a performance pump for this set up.i just fried a piston in my 515ci motor this weekend(only 6 easy hours).i run the same stock pump.spoke to an engine builder today he told me a stock pump isnt good enough.mine doesnt have a regualtor.i have the same exact carb too.fried a piston the first time i opened it up.
tim

Do you have a fuel pressure gauge? If not, this is the first step....everything else is just a guess.

Agreed. Get a gauge on the fuel pressure, even if it is temporary. I doubt the stock pump will support the power you are making. I assume you are using the stock fuel pump that is driven from the sea pump. There are some larger pump sections that will bolt up to the top half of that pump. They are kind of expensive and you could just get a decent electric pump for the same money. If you use the stock replacement, you will just save some labor over wiring and plumbing an electric pump. If you go electric, I would use an Aeromotive Street Rod pump. Here it is at Summit
http://www.summitracing.com/parts/AEI-11203/

This is a very nice pump for your application. They will hold up 10 times longer than a Holley blue. Good luck.
Eddie

glen george -
I'm running a CV Products Marine mechanical on the sea water pump on my 557. I believe the model is no. CV2630. Peak hp for me is at about 5900 RPM but my Humble Little Nova gets way bent out'a shape when I approach 80 on the gps (around 5300Rs), so I can't comment on how the CV pump would work at 5800 RPM on a similar engine.

That said, I had the engine dyno'd at Enders Racing up in Phoenix NY. Enders told me he uses the same pumps (but automotive version) on his BBC circle track engines, and swears by them.

As mentioned, fuel pressure guage is a must!!

I have an aeromotive marine fuel pressure reg hooked up to a gauge, no change on top speed/rpm from 5lbs to 9 lbs. The pressure gauge on my gauge does not drop much. I ordered the KE 120 gph upgrade fuel pump that bolts on to the old housing, the standard fuel pump 861677T on the HP 500 525 is also the one listed for the 454 502 basic models.

if you have fuel pressure at RPM then the pump is not your issue, may need a prop change....Rob

I used the KE120 pump add-on in my last boat, 468CI 177sc and 6psi of boost and the stock 525sc 1050 dominator carb and it worked great, no problems at all.

Bill, You mean like this?

Is there a formula like CI + RPM + CFM = fuel pump gph needed to run a marine engine?