While you have the plates off make sure the shaft is clocked in other words all the U joints are in line and the angle is not extreme.

Thread worth reading...

http://www.offshoreonly.com/forums/g...ive-shaft.html

I guess my next question is IF it is the knock sensor......what in the box would cause it to trip and what damage could occur if it were disabled?

hope you find the problem and get on the water. im excited to see what kind of gains you see. ive been thinking of putting a box on mine and a shorty put wanted to see if anyone has done it on a 25 before. please let us know how you make out. good luck with it!!!

My understanding is the driveline harmonics are what trigger the knock sensor. It is possible to have the sensitivity of the sensor altered, although it has to be done in the ECM.

Sooo.have it sent for a stage 1 ???? I really dont need the extra RPM's but to solve issue I will....

Which set of holes is it installed on ?
( top, middle, bottom)

I'm assuming the U-joints in the box are in phase ?

This spring when I installed the drives, I even phased
the outdrive u-joints with the u-joints in the box.

I use to have a small vibration that you could feel in the floor of the boat at certain speeds, since I phased them, I cant feel it.

It's not that big of a deal to do.

Merc recommends doing it on their jackshaft ( forward
stagger) models.

The box is in the middle position. As far as the shafts being in phase....unsure....but I doubt this guy did it. I also an usure about the carrier bearing and alignment now.

It is dropped off again at the mechanic and hopefully it can be a quick fix for him. I hope buy scanning it is something small like the IAC or something.

I should of done the boat for you!! I could use the help with set up. I would love to try that lower.

Looking back..me too!!

So the engine was scanned and nothing come up. Still unsure of what the issue is. Due to rain he has been unable to water test yet. Could it be something as simple as the engine having been fogged too much during winterization? I filled the tank with 93 Octane to bring up the octane rating of the old fuel but the old fuel had been stabilized. I am going to change plugs, anyone know which ones work best off the top of there head?



As far as the water leak, he said there was a clamp loose on a water line in box so he seems to think that was it but still, no water test yet.