Raising Transom

[RustyGoat]

I have a short transom and a long shaft motor. I installed a Mini Jacker but even with it mounted 2" above transom and a 3/4" block under the motor it still sits too low. Motor is a 9.9 Merc Bigfoot and I topped out at a blazing 7mph yesterday. Motor needs to be raised at least another 2". My idea for raising the motor is to remove the Mini Jacker and use the holes with some aluminum angle inside and out sandwiching a board across the top of the transom. This would also keep waves from splashing over the transom. Good idea or bad idea?

 

[RustyGoat]

Ordered the aluminum angle (2"x 2"x 1/4") yesterday and pulled the motor and jack plate off the boat. Hopefully get the wood all cut tonight so I can start sealing it.

 

[nctlspider]

Sounds plausible. Got a pic or drawing?

 

[RustyGoat]

I'll get a pic later when I go out to finish it up. Just have a couple more holes to drill. Haven't hung the motor yet but so far I like how it turned out.

 

[RustyGoat]

Finished the transom extension just waiting on the sealant to dry before I hang the motor. I used a piece of half inch thick plastic for spacing and as a more solid contact point for the motor clamps. I also sealed completely around everything so that the extension functions as a splash guard. The white sealant dries clear.



I weigh 230 lbs and can stand on this thing with no movement, very solid. I cut the aluminum angle a little long so that in the event I might need to raise the motor more I wouldn't need to buy more.

Other than the aluminum angle and sealant I had everything I needed laying in the garage so total cost was $50.

 

[RustyGoat]

Hung the motor and the anti cavitation plate sits 1" below the lowest point of the hull instead of the 3" below with the jack plate. Hopefully test it out tomorrow if the weather cooperates.

 

[sawmill]

I did the same thing but I removed the top cap off the transom and then added plywood cut to shap the transom. I sandwiched the new piece between 2 pieces of 1/8 thick aluminum sealed with expoy and replaced the top cap. I let the aluminum plate go 2 inches below the old part of the transom and bolted it to the boat. I put the motor on and I picked up the back of the boat from the trailer with my chain fall. No movement what so ever

 

[DrNip]

Looks great. Let us know how it goes.

 

[Attwanl]

I just picked up a 9.8 nissan.. I have to the same thing. What size boat do you?

 

[RustyGoat]

It's a 14 foot boat. With the motor moved forward onto the transom instead of the jack plate and an 18 tiller extension I can face forward running the boat. Originally I was turned around backwards to reach the handle.

 

[RAMROD]

I just added a tiller extension to my 9.8 for that very reason when I built my jack plate, but what you have done looks very nice also!

 

[J Hartman]

I have 2 14 footers with custom built jack plates... I'll have to try and get some pictures for you.

 

[RustyGoat]

I took the boat out today and the transom extension worked great. I'll probably raise the motor another inch or so before the next time out though. Bad news is that I was still topping out at 7mph. I hit top speed at maybe 2/3 throttle and from 2/3 to full throttle I don't gain any speed the bow just lifts. The throttle was also getting stuck again and not returning all the way back to idle when the motor is warmed up. And if that wasn't enough my fish finder started going nuts.

I should have just stuck with fishing out of a kayak.

 

[MDCrappie]

RustyGoat » Sat Aug 10, 2013 5:31 pm[/url]"]I took the boat out today and the transom extension worked great. I'll probably raise the motor another inch or so before the next time out though. Bad news is that I was still topping out at 7mph. I hit top speed at maybe 2/3 throttle and from 2/3 to full throttle I don't gain any speed the bow just lifts. The throttle was also getting stuck again and not returning all the way back to idle when the motor is warmed up. And if that wasn't enough my fish finder started going nuts.

I should have just stuck with fishing out of a kayak.

With a regular 9.9 you should be hitting 17-20 minimum. Not sure about the "Big Foot". You don't mention the year and/or 2stk or 4 stk.

If it's a 9.9 4stk you will likely do better by trying to trade that motor for a different one.

 

[RustyGoat]

Motor is a 2007 4 stroke with less than 10 hours. I bought it in June from a guy that bought it new and used it for one fishing trip before heath problems forced him to sell the boat. Motor just sat in his garage since, said he started it every couple months. I was expecting 15-20 mph from the research I've done. I pulled the carb and gave it a good cleaning and made a minor adjustment to the idle but need to get it on the water to see if it helped.

Trust me selling this motor and buying a non Mercury is a definite possibility. I didn't want a Mercury to begin with but couldn't find a decent motor and this one was a good deal.

 

[RustyGoat]

I did some more research and it appears the prop that came with my motor is not even remotely right for this engine. My prop is a 4 blade 10" 7 pitch. All of the replacement props I'm seeing are a minimum 9 pitch and I haven't even seen anywhere you could buy a 7 pitch prop.

At least it's an easy fix.

 

[Attwanl]

Some long shafts were made for sail boats with a high torque prop... The range of props for my 4-stroke is 5 to 9, so maybe call a merc dealer, they might have more info. I found my info on the nissan web site.