Advice on Outboard setup height.

[skbry]

I have an 1985 bayliner capri 1400 with a 2 stroke force 50hp that weighs 152lbs. While posting a photo Frank Acampora noticed the motor anti-ventilation plate being 2" to low. I went and measured and sure nuff it's 2-1/4" below the bottom of the hull.
So I need to move the motor up.
The transom mount for the motor has clamps on top and thru bolted on the bottom. My plan is to put a 2x2 piece of aluminum sq. tube under the transom mount and the top of the transom (the clamps still contact the transom) then lag bolt the bottom mount holes and seal with 5200. then fill the old holes with 5200 and carriage bolts.
Do you guys see any problems doing by this?

 

[JB]

Re: Advice on Outboard setup height.

Jerry rigs are always a bad idea, skbry. You describe a bad one.

Either an adjustable jack plate or a non-adjustable setback plate will give you a sound, solid mount.

 

[ondarvr]

Re: Advice on Outboard setup height.

If you mean even after raising the motor the clamps will still be on the old (not new aluminum) part of the transom, then it makes no difference if you put the aluminum on or not, it's not doing anything.

 

[Chris1956]

Re: Advice on Outboard setup height.

If the transom clamps still contact the original transom, that plan is fine. However, those clamps are not usually that deep.

Raise it as much as possible, with the clamps still touching the original transom. A 5/4"X2" PT wood spacer works well. Use thru bolts, not lag bolts. Seal old holes with silicone, or glue dowels in them and then silicone. Seal new bolts with silicone as well.

 

[Frank Acampora]

Re: Advice on Outboard setup height.

Well, before you go drilling holes, be aware that two inches MAY be too high and cause ventilation. Always go conservative: Try raising the engine one inch, then an inch and a half, then two inches, testing handling with each setting. If you adequately tighten the clamps, the engine will not fall off for the short duration of testing. Once you find the sweet spot, then through bolt the bottom.



This is an engine similar to yours. It is raised about 1 1/2 inches and since the splashwell is deep you can see the bottom 3/8 bolts and the distance of the clamp pads from the transom top. If you go that high, you will probably need to cut the plastic transom cap.

Kind-of makes you wonder: Bayliner/Force was a combo made by the same company. Why was the transom designed so the engine sat so low? Perhaps it really did perform best at that height. At any rate, test different heights before drilling bottom holes.

 

[skbry]

Re: Advice on Outboard setup height.

Thanks Frank, thats what I'll do this weekend. 2" is the max I can go. I have the original motor manual and it states that the anti ventilation plate should be even with the bottom of the boat. I guess bayliner didn't need no stinking directions. I just might be able to get 30mph out of this boat.

 

[Sea Rider]

Re: Advice on Outboard setup height.

While at plane at 3/4 throttle and with engine trimed out to give a perpendicular engine and a horizontal boat and cav plate with respect to sea line, have a spotter check water flow against tail, flow must pass slight under small upper plate, if possible readjust engine height to match. That's the best position for top speed and nice tight turns.

Happy Boating

 

[5150abf]

Re: Advice on Outboard setup height.

Up and out man, raising the engine is probably the biggest freebie speed increase you can get, I would go as high as you can without redrilling and see what that does, as long as it doesn't blow out to easily and the engine is still getting water you are good and with the setback I bet it will work.

Mine is set up to where it will run trimmed out straight but I have to bump the trim down a bit to turn to keep it from blowing out, it was way to low and I got 6 mph gps by raising it, I doubt all that was from the engine, it may have been partly less current and wind but it gained 6mph just by raising the enigne.

 

[Sea Rider]

Re: Advice on Outboard setup height.

Once you are at the correct trim at full plane and with water passing slightly under small upper plate will achieve top speed and very close turns on a dime, works very well on flat calm seas as on choppy ones. Have gained 2.0 MPH more on a 18 horse by re adjusting correctly the transom height as seen on third pic. Portable motors have unraisable holes.

Happy Boating

 

[Texasmark]

Re: Advice on Outboard setup height.

I too have experienced stellar freebie results in raising an engines...did it several times on several boats. The next thing you will do is find your rpm's out of sight and need to buy yourself a high perf ss prop which would also be cupped, probably 2# more pitch, even with the cup, and the blow out you may have experienced in turns with the new height would probably just be a distant memory and your next problem would be watering eyes to to the high speed wind in your face. But I think you have a windshield so that wouldn't be a problem. Grin

Mark