Johnson 9.9

Nevillizer · Jun 24, 2009

Good day all. I am a newbee (of course). I have been trolling through the site a little and have to say I have learned a few things.

My question is: I have a 78 1432 alumicraft flat bottom boat that I have acquire through my good fortune for free. It came complete with trailer and a 9.9 Johnson (80's model I think). Motor needs the carb refurbished. The question is what is the maximum size motor that this boat will accomadate? I was unable to ascertain this info from the boat itself off of the transom plate, all there is posted is the serial # info. All info is apprciated.

Comment: I will also be making some modifications to the boat to meet my fishing needs and will post picture and idea requests in topic area.

CarlF · Jun 24, 2009

I would say that the 9.9 is about right, 15 max.
probably rated for either 10 or 15.
That 9.9 is probably the best small 2 stroke outboard ever made, indestructible, durable and easy to maintain.

Nevillizer · Jun 24, 2009

OK. Thanks.

crazymanme2 · Jun 24, 2009

Put a 15hp carb on it & away you'll go.

cyberflexx · Jun 24, 2009

my alumacraft is a 1988 1432 with livewell.. Says it will handle a 20hp..

You may need to shim or rework the exhaust on that 1978 if you put in a 15 carb. It wasnt an issue on the 74 and 75 models. I read somewhere that you can feed it more fuel but it will dieout on the topend if you dont do it correctly..Correct me if I am wrong..

Edit: When they designed this series of motors, they designed it as a 15 hp & then detuned it with a different carburetor for the 9.9. When the 9.9hp and 15hp came into being in 1974 and up thru 1978, the only real difference between the two motors was the carburetor. In 1979 they added a shim, part #325038, (one for each cylinder), behind the leaf valves & under the stop plate for the 15 hp, apparently to allow the motor to suck more fuel & air mixture in.

After re-reading the document, I think you will be good with that 15hp carb only