Alaska OD-18

[Fuzz]

First thanks for the great reply to my questions. Jacques, Shine and Cracker Larry all gave input. That is like having an all-star team on my side
The 2x4 is at the level of the boat bottom. This is where the motor was set for my test run. I am guessing it was way too low?

[Fuzz]

This with the bracket all the way up. Is this going to be high enough or do I need to drill higher holes?

[Fuzz]

You guys were asking about the trim. The motor has power tilt and this is all the way tucked under. I would think this is more than far enough? I do not have a tach on the engine but I do have a tinytach that I will try to hook up for the next run. I will take the boat and get it weighed in the morning and post that also when I have it. The prop is 11.6 by 11 pitch. The motor is a 1996 Merc 50 HP. I will reread the posts and make sure I have answered all the questions.
Thanks, Fuzz

[Fuzz]

One thing that might not be clear is the top of the 2x4 is at the level of the boat bottom.
Fuzz

[Cracker Larry]

Yeah that was WAY too low! I think it will be high enough now at the highest position, barely. Can you raise the engine on the jack plate, using a higher set of bolt holes, or is it maxed out at the top? The jack plate itself is too low, but it might work. It looks like you have plenty of trim range.

11" pitch doesn't seem like enough, but you won't know without a tach. I run a 15" pitch on mine. Maybe Cottontop will see this and chime in, he also has a 50 Merc on his OD18.

[Fuzz]

Thanks Larry!
I thought I had read that the bracket needed to be mounted two inches down from the transom cut out. I thought it was way too low when I first tried it but oh well go with what you read. I must have misunderstood what I was reading? Any how I will raise the bracket up. I do want to be able to adjust some both ways if needed. How much do I need to raise it? A best guess is good enough.
Got the weight of the boat this morning. All up with 7 gallons of fuel, the kicker, and everything else I plan on putting in her the boat weighed #1760. Not sure how that compares to what others weigh but it might help for getting the right prop on her.
Thanks, Fuzz

[tech_support]

I would start with the cavitation plate 1" above level of bottom. You might be able to get it 2"+ higher without blowing out, but at 1" above you can eliminate drag being the cause for lack of planing ability. With motor raised, and trimmed down all the way, if you still have problems then its the pitch of the prop. I think my 40 on my FS17 was a 17 pitch

[Cracker Larry]

I thought I had read that the bracket needed to be mounted two inches down from the transom cut out.

Actually the top 2 mounting bolts should be centered 2" below the top of the transom. That is factory standard for engine mounting position and the jack plate is designed to fit in the same location. On mine the jack plate itself is flush to the top of the transom with the top bolts 2" below.

This is a picture of my engine in relation to the boat bottom. The A-V plate is 2 1/4" higher than the bottom. That's where mine likes it best. Your boat is lighter than mine and should perform similarly with a 50 as mine with a 70. Cape Man has a 40 on his and it still planes out nice and runs in the high 20s, and it's a heavy boat too.



I also think you have a prop problem.

[Fuzz]

Thanks Guys,
The plan is to go ahead and raise the bracket up about 3-4 inches and try a different prop. I have to return to work for two weeks so it is going to be a little while before I get this done. I will post the results when I know more.
Thanks, Fuzz

[Fuzz]

Well I got the motor raised up about 4 inches. That made much better! I did not have time to try to fine tune things but I still think it could come up a little more. No sign of prop blow out or cavitation of any type. I had the wife and son with me on this trip. The boy is almost as big as me so we had close to 600 lbs of people in the boat. With both of them sitting a little forward of center and the motor trimmed all the way under the bow still was too high to be able to see over very well. I think I am going to have to change plans and put a center console in the boat.
Does anyone have a good guess where to place it? I looked at Larry B's Yellow boat and it looks to me like placing it even more forward would not hurt as his boat is running bow high.
Fuzz