Need help mounting long shaft motor/ new video added

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seaarc

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I have this motor mocked up to the jack plate and boat with a chainfall. Does this look like it is at the right spot in relation to the bottom of the boat?

normal_25hp_Mercury_001.jpg


normal_25hp_Mercury_002.jpg


normal_25hp_Mercury_006.jpg


normal_25hp_Mercury_007.jpg


normal_25hp_Mercury_008.jpg


normal_25hp_Mercury_009.jpg


Does this look good or does it need to go higher or lower?
Thanks guys

Dave
 
with the set back on your jack plate i think you can go higher. the water will hump up higher behind your stern the idea of set back on a jack plate is to get your motor back into the cleaner higher water in the hump so you can raise your prop up and get more forward energy. that is how i understand it anyways.
 
I was thinking a little higher myself.
Pretty sure you can go to the bottom cavitation plate,just make sure it gets a good water flow(pumps it for cooling)
 
Everyone I talk to and all the motors I have seen have the cavatation plate 1 to 1 and 1/2 inch below the bottom of the transom.It keeps down cavatation and aeration.
 
Where I have it in the pics above it is sitting 5" above the transom. I thought that was the difference between short and long shaft motors. Do I really want to take it higher than 5" over the transom?

Dave
 
shaft_measure.gif
It's going to work where you have it.It might give you better performance alittle higher but then again it might not make any difference at all.
The less drag in the water the better for me,plus my waters can be pretty shallow.
 
So it looks like I can go up to 22" which would probably put it right at the cavitation plate. My transom is 15" and now it is 5" above that so I'll try 2" more and see how that looks. Just did'nt want to go too far up.

Thanks Zum

Dave
 
I like to have the cave plat no lower than 1/2" below the transum. If it's lower you will have control problems as it will try to lift the transume out of the water and porpoising will happen.
WFFF
 
Well everone says go higher so I called the manufacturer of the jackplate to see just how high I can mount it safely. I mounted it as high as they said to go and that puts the cavetation plate about 2" below the bottom of the boat. That's the best I can do with it so I'll let ya know how it performs. Thanks for the help guys.

Dave
 
Well guys the 25 hp motor is mounted, console is built, and steering system is in. Off to the lake in the morning to test it out. Will post pics later and maybe a video if I can figure out this whole You Tube thing. Thanks to all the helpful folks on this sight.

Dave
 
Motor sounded real nice.What a calm day on the water.
Great job,looked like a nice wake off the rear.
 

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