Hey everyone, there is so much good info on the forum I decided to join. I have a new to me 2000 225HP Optimax 2.5L Ser # 0G839677 that runs like crap under way. It starts, idles and revs perfect which is why I thought it was good, should have seatrial'd but we are here now... Took it out for the first time last weekend and the first thing I notice leaving the ramp is if I punch it it stalls. Accelerating a bit slower I got on plane but motor sounded like it was dropping a cylinder intermittently and wont turn over 3K (if my RPM gauge is accurate) so I keep going with throttle mashed to see if it will clear up but after a few miles the engine started bogging, left the stick at full throttle but it bogged lower and lower down till it reached about 1200RPM. At that point I checked the fuel ball and its still hard. I back the throttle down to 1K and its runs ok, little bit of surging but doesn't sound bogged like if the throttle is up so im like "guess we are going back to the ramp at 1K"... about half way back I gun it and it jumps back to 3K but after about 15 seconds starts bogging back down to the 1200RPM range.
This is what I have done so far, at 1K with ears, going to try and re check it on the river this weekend while its under load...
I checked fuel pressure and I got 92 over 82 air
I checked spark with a gap tester and it jumps 3/8 in no problem on all 6
I pulled the air injector connectors one by one and each made the engine run rough so all 6 are firing
Pulled the low pressure pump connector and no change
Pulled the high pressure pump connector and it instantly stopped running (is this SUS? I feel like the LP should keep it running at idle at least)
Compression cold is 90ish on all 6, my understanding is doing the special optimax method will yield 20% higher
Plugs looked ok but each one had a little bit of wet oil on them - is that normal?
Also the beeper had a wire snipped, I reconnected it and getting 4 beeps shortly after start up, I checked the oil tank and the sensor is already bypassed. That points toward TPS right? There is no engine light on the boat, I would like to add one.
Plans...
Check the pressure of LP pump (should be 40PSI from what I have read)
Replace Fuel Filter in engine
Rebuild the pulse pump (why not - its only $35)
Test TPS if I can figure out how - can I replace on sensor at a time? I have 2 stacked. Can I disconnect one at a time? Are they redundant or dependent?
Was thinking about pulling the VST just to check for junk- good idea? bad idea?
What else should I check? Will post results for future reference.
Im leaning towards fuel delivery or TPS but want to check as many things as I can.