1989 Sunbird spray off prop

[rocky5656]

Hi. New to this forum hope someone can help me.

I have a 1989 Sunbird 17 foot fibreglass runabout with Evinrude SPL 88 outboard motor. Always had a problem with keeping the bow "down" at cruising speed. Added a hydrofoil stabilizer, helped a small bit, but not much.

I get a lot of "spray" flying up from the prop area, like in between the boat and the prop, all the time, unless I trim the motor up a "lot", then this brings the front end up even more. Also the back of the engine cover gets sprayed from below.

Why does this happen. Is this a motor height on transom problem, prop problem, boat design problem?

Any help would be appreciated.

Joe

 

[walleyehed]

Re: 1989 Sunbird spray off prop

Welcome aboard!
Sounds alot like you need to raise the engine on the transom...it's very common to get extra spray from the lower if the engine is too low.
Where is the AV plate in relation to boat bottom?

 

[rocky5656]

Re: 1989 Sunbird spray off prop

Hi. Thanks for the reply.

I assume the "AV plate" is the plate above the prop on the leg? I would have to go look, unfortunately it is at the cabin about 3 hours away right now.

Where should the height be in relation to the bottom of the boat (at the back of course)?

Thanks Joe

 

[walleyehed]

Re: 1989 Sunbird spray off prop

The AV plate should be "even with" if not slightly (1" or so) above the bottom when the engine is trimmed level.
If it's "even with", we need to raise it a hole and that will help with many items.

 

[rocky5656]

Re: 1989 Sunbird spray off prop

Thanks for the info. I'll check it out this weekend. Unfortunately I cant report back for 3 weeks (vacation )
But I will report

Joe

 

[SLEEPY1230]

Re: 1989 Sunbird spray off prop

I had a 1990 spl 170 sunbird with a 90 Evinrude and it did the same thing, but alot of the problem was the step on the platform would fall down and cause alot of it. What size prop are you running? I had a 14 x 19 pitch on mine.

 

[rocky5656]

Re: 1989 Sunbird spray off prop

Hi again. I raised the motor 1 hole (it was at the lowest of the 4 holes) and it helped *a lot*. Less splash (but still some), motor seems less sluggish on acceleration and cruising, front end came way down from before.

I used to have to trim the engine right down to the max to get the bow down, now I can run just under level on the trim gauge for the same effect. Cool.

Do suspect I need to go 1 more hole up to get it right, its just a real pain to lift it up square to line up the top bolt holes, used a hydralic jack and a 2x6 to lift it up last time and some helpers. Would put the "wrap around the edge" part of the assembly way above the edge of the boat, and the steering cable would have a big angle to the motor.

Dont know what prop pitch is on there, weird numbers on the prop that I cant decipher. I do now get 5500 rpm wide open, was getting about 5200 before the motor lift.

Joe

 

[walleyehed]

Re: 1989 Sunbird spray off prop

I'd try 1 more hole and see how it reacts if you have the help to do it...
The RPM is much better at 5500, but 5700-5800 would be Ideal with a normal load.

 

[rocky5656]

Re: 1989 Sunbird spray off prop

Thanks for the help.

I take it Sunbird boats closed up in the mid 90's. Any info available on what happened, it's history, etc available? Would be nice to know.

Joe

 

[walleyehed]

Re: 1989 Sunbird spray off prop

Sunbird was owned by the OMC boat group, which fizzled out in the late 90's.