Transom height vs. motor *pics*

[slimjim1987]

Ok, I know this topic has been covered many times, but I've got a strange predicament. I bought this motor, and I thought that it was a long shaft. However, when I put it on my boat, the cavitation plate is about 2 and a half inches above the bottom of the boat. I have included some pics so you can see what i'm talking about.

It looks to me like I made a big mistake. I just wanted to run it by y'all before I took it off and sold it. Please let me know if there is any way that you think I can salvage this setup.

 

[Scaaty]

Re: Transom height vs. motor *pics*

No good. Best bet is find a good dealer of the motor (one of the bigger older service place), see if they have a longshft off a blown motor that you can trade the short one in on.

 

[tashasdaddy]

Re: Transom height vs. motor *pics*

have you had it in the water? what does it do? do you have tale tell stream constantly? long shaft would have to be raised to mount correctly. since it is 5 inches longer.

 

[Willyclay]

Re: Transom height vs. motor *pics*

I cut the transom down on a 1960 Glaspar Avalon so I could use a short-shaft motor. It was easy on that boat because it did not have a splashwell. If that is not an option for you, then how about a jack-plate? Good luck!

 

[Silvertip]

Re: Transom height vs. motor *pics*

It certainly looks too high but I would at least try it. Who knows, it may run like a scalded dog. Just make sure you have a good telltale stream. A manual or fixed jack plate would be the least expensive fix.

 

[JB]

Re: Transom height vs. motor *pics*

Hmmmmm. "Fixed jack plate" sounds like an oxymoron to me. I agree with Silvertip, but I would call it an adjustable setback plate.

 

[kenmyfam]

Re: Transom height vs. motor *pics*

I agree with the "check it out before you move on" theory.
Try it and let us all know how you make out.
Enough cooling water getting through is the "biggie" so if no strong tell tale then shut it down.

 

[slimjim1987]

Re: Transom height vs. motor *pics*

I have not taken the boat to the lake yet, so I will do that next. What is a good website for the jack plate? I'll let y'all know how it does when I take it out, thanks for the help!

 

[tashasdaddy]

Re: Transom height vs. motor *pics*

http://www.iboats.com/Marine_Store/...14949--submit.Search--submit.x.33--submit.y.2
or make your own.

 

[CATransplant]

Re: Transom height vs. motor *pics*

Just a note: What size is that motor and how is it attached to the transom? What kind of boat?

If it's a smaller outboard, clamped on the transom, and the transom is simple, a small cutaway, finished nicely, would probably do the trick. If you needed a full five inches, that'd be one thing, but if you only need 2.5" to get the anti-ventilation plate even with the bottom of the hull, it might just work out OK.

 

[tmcalavy]

Re: Transom height vs. motor *pics*

Your almost in the ballpark. A homemade, offset jack plate would do the job...or you could cut the transom, if you don't especially like the boat.

 

[slimjim1987]

Re: Transom height vs. motor *pics*

Alright....I took the boat out to the lake, and here is my experience. Take note that the lake was extremely choppy!

The motor always had a steady stream of water coming out of the cooling line. It got up on plane just fine. The water, however, was running directly below the anticavitation plate. It also seemed that sometimes I could rev the motor and it didn't seem to hook up as well as other times. I don't have a whole lot of experience with outboards, but maybe this is normal?

Another questions while i'm at it....the motor seemed to bog if I gave it gas too quick. I put 5 gallons of gas in the boat, and 16 oz of oil, so 3 extra oz. Is this because I put too much oil in the gas, or is it because my carbs need some service?

 

[tashasdaddy]

Re: Transom height vs. motor *pics*

probably need to service carbs, and do a link n sinc. changing the angle of the motor may help with the reving, try moving the tilt in one hole. just below the cav plate is good.

 

[jay_merrill]

Re: Transom height vs. motor *pics*

I'm with JB on this one - you need a setback plate that will allow you to drop the motor a bit.

If you look at your prop in your first pic, the tip of the upper blade is actually higher that the bottom of the boat. The reason why you are gettting rpm fluctuations and it feels like it won't "hook up" at times, is because it is cavitating. I'd take a guess at the problem being worse in turns.

Lower the motor a couple of inches and you will probably be ok.

 

[Silvertip]

Re: Transom height vs. motor *pics*

Fixed jack plates are nothing more than a cast aluminum jack plate (ok leave out the jack part) that can be positioned up or down on the boat mounting holes, and then the engine mounted on the plate up or down as required.

 

[mickjetblue]

Re: Transom height vs. motor *pics*

You're just above the "sweet zone" by about 1.5", but that's definitely out.
If the boat/motor combo looks like it would ideal for your usage, you could take
a saw and cut out 1.5" from the top of the transom. You could still add a
jack plate anytime, if needed for another motor.

Not all motors and transoms run true to the 15 and 20 inches specs.
I raised my long shaft motor 1.5" to get the cavitation plate just slightly higher than the
bottom of the boat, and I could feel the improvement overall.
Good luck!