It is twin screw boat .Serial is OK 153 something .You answered my question about low pressure pump.thanks

See I am not so bad to you Motor and I understand now with being twins application,

I never said you were bad to me .All I said was "why not join the site" .It does make it a lot easier to use and doesn't cost much .You wouldn't have to clear your PM inbox everyday ,which you probably have to do now .

Went from VST to cool fuel Gen 1 with return back to the tank during last rebuild, it doesn't use the low pressure feed pump. Was thinking of doing the same thing and replacing the current cool fuel with after market high pressure pump. Don't know if Merc added the boost pump because of the 1/4 ID fittings feeding the high pressure pump or some other reason. My lines from tank to pump are 3/8 ID to reduce the restriction

Was nt sure if you were asking as you already have the low pressure fuel pumps installed wanting to get rid of them or you are looking to install them to help with vapor lock issues and feed the high pressure fuel pump. Anyways Merc always recommended the kit after the fact. Just wanted to make sure about your question.

http://www.amazon.com/Mercury-Mercru.../dp/B005IGSW0G

502 High pressure line
 

Motor, I'm just reading this thread. Mine is 1998yr cool fuel also. Will have to look up what Gen# it is. I had severe vapor lock issues. Both motors.
It's mounted port side low where yours is behind an offshore front engine mount steel plate.

What had been happening I think was when the eng mount plate was installed they had to move the cool fuel box rearward, to make room for the mount plate...the two fuel lines were short and thus pretty tight up against the BOTTOM OF THE OIL PAN. So tight there was no room to insulate or pull them away from the pan. It boiled the fuel out EVERY time i stopped for a while.

3 years ago, i just added extensions in the middle of the two hoses to make them longer to move them a little to get an inch clearance between the pan and the two supply and return filter hoses, And put 2 small pieces of that alum foil covered plastic bubble sheet stuff between the lines and the oil pan. PROBLEM COMPLETELY WENT AWAY. I also put a small sheet between the port side of the block and the cool fuel box and wrapped the fuel filter but these two steps may not be necessary.

Never a VL issue again. The whole time the hot pan had been boiling the fuel.

What I am doing right now is making a couple brackets and moving the pump even more forward so that the two lines that come off the front of the cool fuel pump turn with the tubing 90 degree elbows, are all in FRONT of the steel plate and not crossing it between the pan and the plate under the pan.

NOTE: I did have to cut a big hole in the steel plate for the fuel pump to fit in, but pump and other stuff is now easier to reach and get out if needed. I still was able to use the std pump and attached fuel cooler. Don't need to go back to the tank this way.

By the way, to answer about longer hoses needed. I made a flat plate bracket and just lowered the filter on the front starb side of the motor so the std length hoses would reach.Wrapped the hoses in this foil bubble wrap also. Its HOT down here on the gulf coast in August, still no more vapor lock.

If you wanted to move just the pump, and do away with the cooler by going back to the tank that would probably work also, but as i recall.... you might need a new pumps with the right hose fitting

Very curious what you did. Let us know.
Cap'm Kurt
Lake Charles, La

PM if you need.

I have adapted a 6an compression fitting on that 3" tube by sliding on the female nut and using a brake line flare tool to flare the line, then just screw on your new hose with new flare fitting.