2008 merc optimax 90hp stalls out while trying to plane 1b692367

[dopeonarope]

Hello all, I am brand new to the site, but I heard you are the best at solving optimax problems. What I have is an optimax that is very clean, I purchased it from a guy about a year ago, so I have no idea how long it had been sitting. I havent done much with it except diagnose fuel problems...I rebuilt the injectors (o rings and filter screens), changed out a bad fuel diaphram (it was "pinched" in the cover) and cleaned out the vst...replaced the filter and cleaned the pumps in the vst, while I was in the vst area, I replaced any rubber that looked worn or broken down. I also rebuilt the lift pump and replaced all fuel line/bulb to the vst (the bulb pumps gas and get hard). For the maiden voyage I also ran it on a remote tank, so I knew the fuel was good and dry. The remote tank has good vent. NOW TO THE GOOD STUFF...after all of the fuel work...The engine starts and idles just fine, it will even run for a good long time at 2500 rpms...but when I try to push it past 3500 it dies! NOT GUARDIAN MODE...it goes from 3500 to dead. After that it needs a little throttle to get it to start...after starting i tried to limp it home doing 2000rpms, it ran for about 20 seconds and died...I added throttle again...it started., now i tried limping it home at 1500 rpm...after 20 seconds it died again...I did the same, got it running, now trying to give it more fuel (3000 rpms), same result, stalled after 15 seconds of running. I got it home after multiple restarts. This morning I went down and started it in neutral...no problems, started and idled just fine. I have read in earlier posts that it could be one of two things...1. bad low pressure pump...or 2. a "connector harness" that needs to be cleaned, "spread out a little" dialetric greased and re-assembled. While I had the vst apart I fully cleaned the pump with quickleen and compressed air, a bunch of black stuff came out of it...(maybe I ruined it?) You can hear it running when you turn the switch. I took apart the big round connector harness and it looked corrosion free. What do you think? (and thanks so much for the help.

[dopeonarope]

FYI when I went down to the dock this morning to start it, I only ran it in neutral at the dock. so when I say "no problems" that does not mean everything is solved...it simply started easily and idled at the dock this morning, I never put it in gear.

[dopeonarope]

battery is optima blue top dual purpose agm mca870 cca 750 connections are clean and dialectric greased the distribution block on the engine is unknown.

[JOE54]

need to do fuel psi test when problem is occurring looking for possible drop in fuel psi

[dopeonarope]

i just read that the battery should be 1000mca, could this be the problem?

[JOE54]

dout it

[dopeonarope]

copy that joe, do I need to get fluid filled guages for the task of checking fuel psi test? if so where do I get them?

[JOE54]

may can rent a set , but yes they work really good