Carburetor

[Mallett]

I think we all agree, it’s not the carb. Where to start finding or figuring out what the problem is. What goes wrong when you over heat the motor? Also I pulled the power head off the Kf7 and the pistons only travel an inch up and down I thought the gears were bad in the lower unit, guessing it’s something else in the motor that stopping the pistons from moving up down the full stroke.

[RICHARD A. WHITE]

Check compression on the power head… should be over 110 psi, best if higher.  Others can tell you what it actually should  be but if you cooked it, loss of cooling water, then you probably smoked a piston or 2….

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[Mallett]

So let’s say it’s smoked, where would one start, go through the manual and start talking the power head apart?
Off to go buy a compression tester.

[Waunnaboat]

I don’t know much(or anything specifically regarding) Mercury motors, especially the racing variety, but there could be something with the impeller having broken and jammed the motor? Were you running it on your Midget Flyer?

"Outboards seem to multiply exponentially..........I find that for every finished project, there are two more waiting to be completed."

[Tubs]

When a motor gets hot the oil becomes thinner. The metal parts also expand. If you don’t stop the motor!!!!!!, at some point, there is no oil left between the metal parts. The motor begins to tear itself apart until it locks up.  As it did run for a while, it was likely an impeller failure as Waunnaboat suggested. You should start by looking for another power head. Kf-7’s are plentiful and not as pricey as the KG-7’s. Finding a Super Ten that still has 110+ lbs of compression is not impossible but your odds aren’t good. I had had a Kf-7 with 110 + lbs of compression, and another with 90 lbs. While there was only 1 or 2 mph loss at the top end, the motor with 90 lbs. suffered from a significant loss in acceleration. Still the motor was a lot of fun and didn’t cost much. Video link –  https://www.youtube.com/watch?v=sm4M0xnXm-I&t=65s   

A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.

[RICHARD A. WHITE]

I have a rebuilt KE7 sand cast block that I had rebuilt, I have less than 15 minutes run time on this motor.

This is a complete motor, only issue is walnut shells from my media blaster inside the tank.

I had it for sale for $250 and got no bites…..

It was built by someone who knows these motors and I am pretty sure sine they themselves race these things, that it was done right.

I will never use it..   Want me to bring it up to Tomahawk? You can look it over if you wish.

If you know me you will realize that this motor is just too small for my large frame… It will move a boat with me in it, just that I will never see the full potential.

 

That is why my original Wizard Super 10 is sitting on the rack as well… I either need to run Rowboat motors or 20hp and up motors…LOL Easier than losing 50 lbs…lol

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[Mallett]

Yeah

[green-thumbs]

Tillotson carburetors are listed by letter and number
with application for AJ and other series. If you have a
carburetor list gives motor.
List can also be used to find
OEM carburetor for a motor
with a wrong or missing Tillotson carburetor.
Covers AJ and other series used
on cars, chainsaws, outboards,
small enginess.
Louis

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Sam M.

[Author]

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