Those of you that have 575SCi's. . . . .
 

What does fuel presure guage read at idle and various RPMS?

trying to determine if I have an issue.

Thanks!

Re: Those of you that have 575SCi's. . . . .
 

Bill,
Idle - 34 psi
5000 rpm - 28-29 psi
Jamie

Re: Those of you that have 575SCi's. . . . .
 

Hey Bill last time I was out in my Top Gun the port fuel gauge went to 90+ found a broken wire at the sender in the fuel rail which is right under the air cleaner on the port side of the engine


Drew

Re: Those of you that have 575SCi's. . . . .
 

I bought the boat used; and from day 1 both engines have read 20-21 lbs from idle to WOT. Since both motors were identical, I assumed that was normal for a TG & 575SCi's.

Well, the diapham fuel pumps have been leaking fuel into the oil of the seawater pump and thus trashing the seals. Merc "JUST" updated the mech fuel pump to a new/revised design mech pump. They have been back ordered until last week. So last week I put on brand new sea water pumps and the new revised mech. fuel pump. At idle I am still getting 20 - 21 lbs. At 4000ish it dropped to about 18 lbs. I didn't take it into boost, as I was unsure of a possible lean condition. (FYI - I still have soot on transom)

I asked the tech to call Merc, and Merc said I should be at about 30 PSI. So now the tech will be looking for a problem. 1st thing he is going to do is hook up a mech fuel pres gauge to rail and see if gauges/senders are wrong. (btw - all wires on senders are good clean connections)
If mech gauge shows low, where would you look for fuel delivery restrictions on an '02 Top Gun???

Thanks in advance!!!!!

Re: Those of you that have 575SCi's. . . . .
 

Run an independent mechanical gauge on your fuel rail, I think your senders might be off.

Size Matters on the post above has the numbers my friend with 575sci is running also

Re: Those of you that have 575SCi's. . . . .
 

Mine shows about the same as yours Bill right at 20-25psi.

Re: Those of you that have 575SCi's. . . . .
 

Bill,
Do you have electric pumps on the bulkhead feeding your mech. pump on the motor? Mine have regulators on them so you can adjust fuel pressure.
Jamie

Re: Those of you that have 575SCi's. . . . .
 

check the regulators....they get stuck at times and may even obstruct the fuel delivery

Re: Those of you that have 575SCi's. . . . .
 

I have stock 575SCi's w/ cool fuel.
There is the (new) mech fuel pump that feeds the merc fuel pump which is monted on the motor. If there is an adjustment for this, I don't have a clue.

Re: Those of you that have 575SCi's. . . . .
 

I didn't trust the gages on the dash so I put pressure gages on the fuel rail. The rail gages read between 28-30 and the dash ones read 5-7 less.

Be careful, these motors don't like low fuel pressure.