power loss 502 w/ fuel inj.

[tommy817]

i'm running a 502 motor in a 27ft. formula. motor has roller cam and roller valve train, also stainless marine exaust,adjustable fuel reg. b&m air intake,re-programed ecu. problem is engine tops out at 4000-4200 rpm. runs strong to that point then lays down. throttle working o.k. but seems there's about 1/4 throttle left with no additional rpm. any help appreciated,can only afford to do my own work. tommy.

[Beer-30]

i'm running a 502 motor in a 27ft. formula. motor has roller cam and roller valve train, also stainless marine exaust,adjustable fuel reg. b&m air intake,re-programed ecu. problem is engine tops out at 4000-4200 rpm. runs strong to that point then lays down. throttle working o.k. but seems there's about 1/4 throttle left with no additional rpm. any help appreciated,can only afford to do my own work. tommy.
If you have already changed fuel filter(s), hang a pressure gauge on the fuel rail. Sounds like loss of fuel.
The inlet to the pressure pump is known to get clogged. If it is anything like the 496s, there is no filter before the pump.

[tommy817]

thanks for the info. there is no filter before the pressure pump. only stock fuel filter which is always changed. fuel pump is new(belt driven) as of last season with the new crate long block. i believe the regulator is set at 40psi. still cold here in jersey, but getting set up for this season.....t.

[mike37]

do you have the right prop
if the pitch is to big you will run out of power before you hit the rev limiter

[haysonj]

I had that problem with my 6.2 with a procharger the platium plugs had too much gap and the blower would blow out the fire at 4000 RPM may want to check your plugs