I could really use some advice here. I picked up a used Bass Cat Pantera III in the spring off of ebay with a Merc 225 carb (94/95). when purchased it was runnin ratty & I assumed it was just a carb rebuild needed. I rebuilt it but didn't solve the prob so I brought it to a local Merc shop. I had it at a shop for 3 months & they could NOT find the problem. Finally brought to another shop but still not right. mechanics are stumped.

here are the symptoms & what was done to date:
About the motor:
Merc 225 carb (94/95)
It is equipped with a Trophy 25P prop with plugs removed.
owner claimed it ran fine when put away in the fall. was winterized, fogged, & fuel stabilized.
has around 110-120psi on all 6 cylinders
new powerhead 2 yrs back
oil injection disabled (running mixed fuel)
According to Merc, this motor does NOT have a safe mode if there is a low oil/hot case warning
(note - the dash worked when I purchased it but does NOT come on now - yes I checked the wiring - back light works but not LCD) cant tell exact rpm figures.
has a mechanical jack plate but not sure how to measure proper height for this application
Symptoms:
with 1/4 tanks & 2 adults It would not holeshot.
It would NOT pull more that 2K rpm and just bogged.
It WILL rev out fine in Neutral and in gear on a trailer.
only bogs under a load
if you trim it back enough (at the dock) it will spool up once lifted enough.
What was done:
fresh fuel added
rebuilt carbs & changed plugs. - no effect.
replaced all 6 coils - no effect
drop tested all cylinders - all ok
compression 110-120psi on all 6 cylinders
replaced TPS - no effect.
rebuilt fuel pump - no effect.

Finally I replaced the ECU. (after 2 Merc Certified mechanics, 4 months and more than $2700 in service time, this was the last thing they could think of)

It now runs smooth, & will pop with one adult, but with 2 adults, it really lugs out of the hole. lots of cavitation but eventually will get up on plane & runs clean up top. I was NOT able to push it to max RMP due to water conditions but it was still accelerating past 53mph (gps) when I backed her down. It would NOT get on plane with 3 adults at all. cavitated like crazy & then died when I backed off.

Here is my question... I'm told that this is a bit aggressive of a prop for this boat/motor, but shouldn't a 225 be able to pop this thing? I'm considering buying a Fury 24p but would love to hear some feedback first. could jack height be the issue?

any Ideas???

Robert

kkkk

go down 2 pitches of prop