Merc 100 hp 2+2

[boatinnjax]

Help! My merc 100hp 2+2 is bogging down at WOT and often at part throttle. Rebuilt fuel pump last year - no real help. Got a used one free a month ago, it seemed to be better at first but now is not. Inline pressure guage indicates 2-3 psi at idle but it drops off as I throttle up. Manual says it should increase as apply throttle to 6psi at WOT, I'm nowhere close. My wife hate me throwing money at parts and wants to cut me off.
Question: Will anything else cause fuel psi to drop like this? I think all the fittings and connections are tight.

Thanks for any help!

 

[emckelvy]

Re: Merc 100 hp 2+2

Well, you either still have a problem with the fuel pump, or there's some other type of restriction in the system somewhere. Ethanol-blended fuels are really chewing up these older fuel systems. I did a 4-cyl 115 earlier this year that had fuel pump check valves all crumpled-up due to alcohol. Some of the fuel lines had issues and I also replaced the fuel bulb as these are known to cause problems. Merc has put out a revised primer bulb as a result.

Check out this linked Mercury Marine TSB on fuel starvation, hopefully you'll find the info useful:

http://dc151.4shared.com/download/101684956/9767ea93/2001-17_Fuel_Starvation.pdf

HTH...........ed

 

[boatinnjax]

Re: Merc 100 hp 2+2

Thanks, I'll give it a look-see.