Who's (2520) motor is up the highest?

[channel_surfer]

Well I'm planning my winter maintenance, and one of the things I plan to do is raise the motor at least one hole, especially since I have the 4 blade wheel now. From memory I think I am in the second position from full down, so I can go up one or two holes. Is anyone running in the very top position?

FWIW, I have absolutely no blow out or cavitation in rough seas or even the sharpest turns as I am set up now. With the stock 3 blade I had to trim way down and make wide turns or else I would lose the prop bite, but the rev 4 seems to be a world ahead of the 3 blade in this regard.

I would rather not have to pull the boat twice to adjust the motor, but would like to go as high as possible to increase effeciency.

Thoughts?

Thanks!

 

[DaleH]

Is anyone running in the very top position?

With the stock 3 blade I had to trim way down and make wide turns or else I would lose the prop bite, but the rev 4 seems to be a world ahead of the 3 blade in this regard.

We need to be careful here to compare apples to apples. My 25" leg 225hp Ob is mounted on a mod-V hull (14-degree deadrise) 2520, on a bracket, and I run her in the highest available mounting hole. 16-degree deadrise hulls, even with a similar bracket 'might' have a different running attitude ... I don't know. I am not using a premium prop so I do need to make darn sure the OB is tucked in to make an agressive turn while @ cruising to higher RPM speeds.

If lots of offshore use, in seas, top position could cause too much blow out (due to wave/sea actions), even though the prop is trying to stay hooked up. When I run way out for toona I do find I sometimes need to tuck her in a little more than I would otherwise whilst on calmer seas, but since I run a fuel computer, I have noted I am talking miniscule loss (if any) of efficiency here.

Without measuring it, I'd venture to say my OB vent plate is 2" above the bottom of the hull. But remember, my motor has a 29" setback. In 'theory', with OB brackets, they say you can raise the motor 1" for every 12" of setback.

 

[channel_surfer]

thanks Dale. For reference, I am running a notched 16 degree hull. No bracket.

 

[DaleH]

With no bracket, thus no setback ... not too sure how much IF ANY you could reasonably move it up.

 

[channel_surfer]

My last boat was a 23' wellcraft with a notch. I bought it used, confiugured with the cav plate even with the hull bottom as is typical. I was able to move it up one hole and picked up holeshot, and about 3mph top end. Went up another hole and lost all traction so moved back down to one hole up from where I bought it, which ended up being 1" above the bottom of the hull.

There is room for experimentation and improvement, just not as much as with a jackplate or bracket.