I'm hoping yall can give me some good advise on this. I searched on google and that's how I fount this forum, a few posts from pappy telling people how to set up jack plates on jon boats.
I have a 97 grumman 14' with a 25hp johnson. It has a 20" transom, but the cav (anti vent) plate sits 2" below the bottom and a lot water shoots up the leg. If I set the trim pin in all the way it sprays up so much water I can barely see the motor! So I order the mini-jacker from basspro to raise it up, along with a tach and water pressure gauge.
I installed the gauges (not the jack plate yet) and borrowed a gps and found that the boat did 27mph with the motor in the highest trim setting. The tach showed 4600 rpm but I had it set at 6p when it should be 5p, so I think it was really turning 5500. That works out to 13% slip with the 10 x 13 prop. I think I can get this at least in to the low 30s, if not mid 30s. I ordered a solas amita 4 blade 10x15 prop. I went with the 4 blade as I figure it'll let me raise the motor higher because it'll have more bite than a 3 blade.
So how high should I set the motor? The mini-jacker isn't adjustable itself. I saw a post where pappy suggested 2-2.5" above the bottom. Since I'll have a 4 blade prop I was thinking of starting at 2.5". Any thoughts?
I have a 97 grumman 14' with a 25hp johnson. It has a 20" transom, but the cav (anti vent) plate sits 2" below the bottom and a lot water shoots up the leg. If I set the trim pin in all the way it sprays up so much water I can barely see the motor! So I order the mini-jacker from basspro to raise it up, along with a tach and water pressure gauge.
I installed the gauges (not the jack plate yet) and borrowed a gps and found that the boat did 27mph with the motor in the highest trim setting. The tach showed 4600 rpm but I had it set at 6p when it should be 5p, so I think it was really turning 5500. That works out to 13% slip with the 10 x 13 prop. I think I can get this at least in to the low 30s, if not mid 30s. I ordered a solas amita 4 blade 10x15 prop. I went with the 4 blade as I figure it'll let me raise the motor higher because it'll have more bite than a 3 blade.
So how high should I set the motor? The mini-jacker isn't adjustable itself. I saw a post where pappy suggested 2-2.5" above the bottom. Since I'll have a 4 blade prop I was thinking of starting at 2.5". Any thoughts?