Fountain38

Ok here goes--I'm currently have 30-32 psi fuel pressure on my port engine. It backfires occasionally when coming up on plane, which is why I checked fuel pressure. I changed my cool fuel electric pump and it still maintains the same fuel pressure (30-32). The other engine pulls 38 psi and runs ok. Any ideas where the problem is? I haven't change the silver fuel filter yet--tomorrow I will. Fuel is clean, and there does not seem to be any restrictions anywhere. The motors are stock 500 efi with no modifications. I'm lost and would appreciate any ideas. Thanks


Engines are in a 36 Eliminator Daytona

haulywood2

I would change the high pressure pump that would be the quicksilver pump....Good luck man

Young Performance

Start by changing the water seperating filter. If that doesn't work, then hook up a temporary fuel source(like a 5 gal. plastic tank) and run the engine with that. That will eliminate the boats fuel tank, anti siphon valve, pickup, and hoses. If the pressure is good then you know where to look. You will need to hook up the fuel source right to the fuel/water seperator. Good luck
Eddie

Fountain38

thanks for the quick reply. I have already changed the fuel/water sep filter, but the idea of hooking up directly to fuel intake sounds good. Your right it would rule out the tank problems. I thought the high pressure fuel pump was the cool fuel pump located below the oil pan? Is it not? Thanks for the ideas

Strip Poker 388

iTrader: (6)

you also have 2 regulators on it,they make a kit for the uppper one that makes it ajustiable, mine didnt work real good.also there is a screan in line up there,but shouldnt be anything there

are ya checking the presure at the fuel rail orfice thingy.

how does it run on the top in? low pres should make it lay down
Rob

Fountain38

Thanks Rob for the help. The boat runs great on the all through the rpm range except an occasional backfire thru the intake plenum. I'm going to work on it today. I'm trying to get it ready for the shootout weekend coming up this weekend.
Thanks

Strip Poker 388

iTrader: (6)

To me if the fuel pressure is to low,on the low rpm it would be the same if not more on the top,so if not enough fuel at wfo it would lean/laydown .Like when you over rev a 2 stroke dirt bike, or backfire up top.

another thing, you checking the pressure with the vac hose off and blocked,are ya watching the fuel pressure thru the rpm range, are ya checking it at the shrader valve on the fuel rail.
does it have the block fuel pump?

if it pops getting on plane it might not be enriching it , like a power valve,squirter's on a carb.

I bought a kit from Arizona speed and marine, they said something about 48-52psi,best I can remember, it would not increase, they wouldn't help,bastards. thats why all the Arizona speed bad biz thread,

ck the vacuum hose, leaking? did ya ck the screen at that reg?maybe a sensor gone bad making it think it need lean getting on plane, ck all the sensors, take them off and reconect them,bad connection

next thing is swapping parts from side to side,I know that sux.

ck the fuel cooler is stopped up, fuel getting hot????

air cleaner clean?

I guessing here

Rob

if this doesent work ,get drunk with ya bud talk it out and youll dream it that night