Water Spraying with outboard motor and other problems (video/pics inside)

[Iandayen]

I have a 14ft 1960 Sea King fiberglass boat. I believe it's what they call a flat bottom boat or jon boat.

I have a 1968 mercury 50 horsepower thunderbolt outboard for my motor.

Motor runs great, boat floats.

Here are pictures of boat and motor to give you guys an idea of what i have.

http://i32.tinypic.com/15i6uyp.jpg

http://i31.tinypic.com/2j6a80p.jpg

http://i25.tinypic.com/2uo11ys.jpg

First - When at higher RPMs I get quite a bit of water spraying behind the boat.

Here is a short video of the spray in action.

http://www.youtube.com/watch?v=CapA3DviUy8

now, I had a problem with spray AND water coming over my motor hinge (diagram in pic http://i27.tinypic.com/10ru3it.jpg - not my motor but shows you how water was coming over) but I was able to fix that by moving my manual trim settings to the second to last hole away from the boat, now I don't get water over the hinge, but I still get all that spray.

My Cavitation plate at that trim setting sits about 1" - 1 1/4" below the bottom of the back of my boat.

Also, when I am at WOT my boat tries to turn to the right by itself and will start listing to left or right side randomly. If I go to WOT, get up on plane and then throttle back down a bit I can hold pretty steady, but she still feels a bit unstable, it definately turns to the right a lot easier than to the left.

Any suggestions on fixing these problems? I imagine smart tabs would help with the listing left and right at WOT but the water spray (as far as I know) shouldn't be like that I think.

But I am pretty new to boating, this is my first boat, I took that motor which hadn't run in 6-7 years and got it going strong (new impeller - rebuild fuel pump, cleaned, etc..) and would like to get her running smooth on the lake.

 

[Fl_Richard]

Re: Water Spraying with outboard motor and other problems (video/pics inside)

The motor is too deep. The ventalation plate should be even or slightly higher than the bottom line of the hull.

The pull is beacuse of the spin from the motor, do you have a little adjustable fin under the ventalation plate? It shouldnt be straight, it should be twisted slightly stbd or port depending on the roatation of the motor to counteract the right pull.

 

[Iandayen]

Re: Water Spraying with outboard motor and other problems (video/pics inside)

The motor is too deep. The ventalation plate should be even or slightly higher than the bottom line of the hull.

The pull is beacuse of the spin from the motor, do you have a little adjustable fin under the ventalation plate? It shouldnt be straight, it should be twisted slightly stbd or port depending on the roatation of the motor to counteract the right pull.

there is a fin.

if boat pulls to the right, which way should the fin be turned?

 

[steelespike]

Re: Water Spraying with outboard motor and other problems (video/pics inside)

Boat is not a flat bottom it is gently rounded.A flat bottom is exactly that
and a Jon usually has a squared off bow with a slight V at the bow.
If the motor pulls to the right turn the rear of the tab to the right.
What is the rated hp of the boat? If the motor has height adjustment holes
raise the motor to a point just before venting(cavitation) becomes a problem.
When you trim the motor out does the bow come up?
Or does the boat still seem to be glued to the water?

 

[Iandayen]

Re: Water Spraying with outboard motor and other problems (video/pics inside)

boat stays in water fine , it levels out even at that far trim setting.

With it in, for the 30 seconds I went it seemed a lot more stable with it trimmed down and it seemed to get on plane quicker, I just got a LOT of water over my motor hinge into my transom.

 

[Iandayen]

Re: Water Spraying with outboard motor and other problems (video/pics inside)

it came with a 35 horse motor on it, but from what I have been able to find online they are rated for up to 50 horsepower.

 

[steelespike]

Re: Water Spraying with outboard motor and other problems (video/pics inside)

At full trim the bow should come up and boat should run on the rear half to 2/3.
If it lays down flat pushing a pretty good spray up near the bow there may be a hull problem keeping the bow down.This can cause the boat to lean randomly left or right as well.Raise the motor vertically as I suggested.Then see how the boat trims.

 

[Frank Acampora]

Re: Water Spraying with outboard motor and other problems (video/pics inside)

Slightly above the cavitation plate there is usually a deflector plate. This functions to keep water that hits the leg while the boat is moving fast from riding up the leg and into the splashwell. If the engine is set too deep in the water, this deflector plate will not work. Raise the engine until the cavitation plate is at least even with the bottom of the hull. That should stop water from migrating up the leg and into the boat. You can even go a bit higher for better performance but this varies with hull design.

 

[Iandayen]

Re: Water Spraying with outboard motor and other problems (video/pics inside)

Appreciate all the help guys, going to go out and check out some options for raising my motor up a bit tomorrow.