96' 150 Mariner EFI high pressure fuel problem

[RollTideFan]

I am looking at purchasing a boat with a 150 Mariner Magnum EFI on it. It seems to be really cold natured and hard to start. After running on muffs it will start right back up but after letting it sit about an hour its kinda hard to start back up. I have not had in the water yet wanted to go through everything before taking off in it. I tested the electric fuel pump pressure and it was 37 psi. which is correct I believe. My concern is that as soon as the elec. pump cuts off the pressure will fall to 0 psi. within 2 seconds. I have not been able to dig up any info. on whether this pressure should hold or dump immedietely. I don't have a manual and really don't want to buy one until I know if I am going to buy the boat. Any help would be appreciated. Thanks!

 

[ufm82]

Re: 96' 150 Mariner EFI high pressure fuel problem

This may not help and I'll say up front I don't know about your engine but... EFI engines in the Ford line up have a check valve in the fuel pump that keeps residual pressure in the line after the pump has been turned off. If you've ever touched the Shraeder valve on the fuel rail on a Ford you know that it will spurt out bit of gas when the valve is depressed. When the check valve fails the fuel can empty from the fuel rail and cause hard starting. I've replaced a number of fuel pumps in Fords over the years because of this failure. So your issue could very well be just that but without knowledge of the system I'm only guessing. My '93 Merc 150 is basically the same engine so I will watch the responses here with equal interest.