1957 Johnson 7.5 doesn’t want to stay running

[Newguy07]

1957 Johnson 7.5 AD-11. New to me, previous owner rebuilt the carb. Motor fires up with just a few pulls.. sounds great until you completely close the choke, then, it will run for a bit then start to peeter out, a little bump of the choke and it takes rite back off.. also does not want to run below the “start” position, really anytime.. I replaced the fuel lines. I’ve tried adjusting the “slow” and “high” speed settings but In all honesty I am not familiar with this old motor at all. It seems like it should be an easy fix, I just don’t want to make the wrong move and make it worse.. help!?

 

[racerone]

?---Close the choke or did you mean OPEN the choke flapper ??---Set high speed at 1 turn from gently seated.----Set upper ( low speed ) at 1-1/2 turn out.----The motor should start and keep running with those initial settings.-----Then you MUST make final adjustment with motor in gear and loaded.----First adjust high speed for maximum RPM----Then adjust low speed at idle speeds.

 

[Newguy07]

I know that was probably very simple to you but all I needed was that starting point!!! Thank you so much for your time and knowledge!! Started rite up at those settings, a few minor adjustments from that point and wala!! Idles nicely and everything!! Thanks again!

 

[Crosbyman]

how is the impeller… new ?? maybe you should consider popping a new one in great motor by the way
http://www.youtube.com/watch?v=SVOedhzPP7M
http://www.youtube.com/watch?v=EY2HrEdp5vg

looks difficult but… it is not if you damage the base gasket order a new one specific to your fd11 (patterns similar for each)

be very careful with the carbon seal parts under the power head .. it is brittle

 

[Newguy07]

It’s in decent shape but I’ll still take a look at your link.. another question for you guys, would there be a negative (damage causing) issue in pairing my 7.5hp along with a 5.5?

 

[racerone]

Motors just push on a transom.-----No different than 2 mules in front of a cart.----How would you know that each mule is pulling the same ?

 

[Newguy07]

Where are you guys getting parts for these motors? Also are you buying hypoid oil at your local auto parts store or getting a specific brand?

 

[Crosbyman]

try a dealer try Iboats try TIM's outboard I think you need to buy the book CHEAP OUTBAORDS it is a great book for

surf the net try classifieds on AOMCI.org join a club

 

[oldboat1]

Final needle adjustments should be made on a boat, in the lake. But you can get it close using the initial settings mentioned above. Test in a barrel with water about half way up the leg. With the motor warmed up, adjust the slow speed needle clockwise (leaner) until the engine backfires or stalls, then c.clockwise about 1/8-1/4 turn. See if the motor goes into gear without stalling (low idle). Don't run the motor at sustained high rpm unless in the lake.

Test cooling by putting the heel of your hand on top of the head. If too hot to touch, it's running too hot. In any case, the impeller should be changed out on a "new to you" motor before lake testing. The powerhead needs to be removed, but that is not difficult.

 

[merkdawg0084]

You can also try marineengine.com for parts or vintageoutboards.com