# Mercury short shafts not 15 inches?



## Amdek (Jul 14, 2011)

Hey guys, new here and first post. 

Doing things backwards, got a motor, built a trailer, and finally got a boat the other day (tracker 14, from bass pro) :lol: 

Anyways the motor I picked up is a mercury 6HP 4 stroke short shaft.. Finally put it on the boat and the motor sits pretty low. The anti ventilation plate is about 2.5 inches below the bottom of the boat. I measured the distance between the anti ventilation plate and the inside top portion of the transom clamp and sure enough it is ~17 inches, actually a bit more. Thought I was crazy so I went to the bass pro shop with the tape measure and all the smaller motors "15 inch" short shafts are ~17, all the long shafts are ~23 inches. 

Transom on this boat is exactly 15 inches. What should I do? Run the motor deep, build a transom extension... surely I'm not the only one with this kind of problem.

Thanks all in advance,
-mike


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## Zum (Jul 14, 2011)

Short shaft=15-17"s
Long shaft=20-22"s
Seeing that you bought a 6hp,I'm thinking your looking just to motor around.
It doesn't seem like your thinking top end speed so...that outboard,a few inches below the bottom of the boat won't hurt you to much.Unless your concerned with hitting rocks etc.,you probably fine how it is.
Try it how it is,then jack it up with a peice of wood as high as you can and see if it makes any difference.
I don't think a 6hp would plane your boat but could be wrong.



Forgot to add..welcome to the site.


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## Amdek (Jul 15, 2011)

thanks for the reply. Don't get me wrong, speed isn't a huge issue it's just i've seen first hand how poor an outboard hung too low performs. I'm looking for every mechanical advantage here dealing with a mere 6HP  

Mostly looking to see if anyone else has put a vertical extension on a transom, and any tips...

Here are some pictures of the rig so people can see how it sits.

Edit: also stupid question here, do people leave their outboard hanging on the boat when not in use? will it do any harm if left on for a few weeks?? (again sorry if stupid question, i'm new to this whole boating thing)


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## Zum (Jul 15, 2011)

People have down extensions or homemade jackplates on this site all the time.
Go to the search function(top right of any page of this site)and type in jackplate or homemade jackplate,you will get all kinds of ideas.
You can probably raise it probably 1.5"s just by putting a spacer(block of wood) between the boat and motor.Just make sure the clamps have a good connection to the boat.
I always leave my outboard(30hp) down,just like you have it,all season long.
People hardly never take their motors off,in the larger/heavier sizes.
Small/lighter outboards are easy to pick up...easy to take away...or steal.
People are evolving to have sticky fingers,just something to think about.


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## jasper60103 (Jul 15, 2011)

I agree with, Zum. The 6hp will get you around the lake, but I'm not sure it will plane your boat. Check the capacity plate and get something closer to the max hp rating if you want better performance. 
That's a nice motor for fishing though, especially small water. That 6hp should troll nice and quiet and sip gas. Enjoy.


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## flatboat (Jul 15, 2011)

i had a shop bend a piece of 1/8 aluminum to fit my transom . i think i bent the top 2" for the transom 1 ft frnt and back . cut a piece of 2x4 2" x1 1/2" works fine 
'your results may vary' ...i would tie to the frame those eye bolts might split your runners,just a thought


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## Amdek (Jul 15, 2011)

thanks again for the replies. Found tons of info searching for jackplates.. luckily I have an industrial metal supply down the street, figure it should be a piece of cake to fab up something out of 1/4 inch aluminum.. Will post up pics and lake results for the heck of it early next week


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## Amdek (Jul 18, 2011)

ok guys, an update for anyone that cares,

Made a transom extension out of 1/4" aluminum, 1/16th inch aluminum (spacer for the inside of the transom) some scrap wood and new bolts from ace. Piece of cake, and VERY strong Total cost was ~24$

The cavitation plate now sits about 1" above the bottom of the of the boat (as opposed to 2+ inches below before)

I'm assuming the height should be good now, plus I will have to try and hit rocks now hah. Stupid question, does anyone know where the small merc/tohatsu/nissan 4 strokes impeller inlet is? 

Thanks again,

-Mike


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## Amdek (Jul 25, 2011)

last update guys,

After some fine tuning (carb on the merc. needed to be cleaned to run WOT) and actually lowering the motor an inch from where I had it, everything is square!

GPS confirmed 14 mph with me and a passenger. Not bad for 6hp on a 14' boat and around 400lb of human weight on board


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## Zum (Jul 26, 2011)

Throws a nice wake,nice numbers as well.


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## flatboat (Jul 26, 2011)

its amazing how it runs when its right


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