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Oddities in starting procedures: 1963 Johnson 9.5

C

CMOS

Regular Contributor
Howdy All,

I have a very well running 1963 Johnson 9.5, but I am perplexed as to how it behaves when the outside temperature is hot here in Texas, 90-100 degrees.

I first got this motor running in winter of 2015. Cold starts are done as usual: prime, choke, throttle to neutral hard stop, pull. Works well.

In the summer when the outside temperature is hot, boat just put in the water, this motor seems to only start with no choke (understandable) and with the throttle only in the lowest "Shift" position. Meaning, if I advance the throttle to the neutral hard stop, it floods and will not start. I can literally smell the excess fuel in this position.

Back off the throttle to the "idle" or Shift position, and she starts after 4-6 pulls. Runs like a scalded dog all day long.

So, why doesn't this motor start with the throttle in the "START" position? I would think it would start easier due to the timing being slightly advanced, in comparison to the "Shift" position.

Thoughts?

CMOS
 
fdrgator said:
It may be flooding due to pressure buildup in the tank while not running. Try leaving the cap loose to verify.
Click to expand...

Doubtful. When I pull the boat out of the water I leave the motor running and pull the fuel line to let it starve. So, the next time I go out, there's no fuel in the carb. I re-connect the fuel line just before backing the trailer in the water.


mf70: I had an Old Timer, who is very experienced with these older motors, tell me, "These motors are females, so you just have to find out what makes them happy." Truth!

I'm not worried about what I'm experiencing, I'm simply technically curious, and want to learn more.


CMOS
 
kimcrwbr1,

I would think if the float was set too high I would have problems other than this specific instance: starting the motor for the first time on hot day.

I connect the fuel line to the motor right before I back the trailer in the water. As far as motor position, yes, I trailer and launch with motor down in the running position (my trailer sits high). What is your concern with this practice?

Thanks,
CMOS
 
For what its worth, I don't think they made the "stubby" until 1964 and ran them through 1973. The original steel 6 gallon OMC fuel tank is self venting..... if you leave the coupling attached at the tank fitting. If you disconnect the line at the tank, then it will for sure build pressure in the hot sun, but maybe you don't have the original tank anymore. There is no problem with keeping the motor in down position when at the landing as long as it is deep enough, of course.
To solve your problem, I would consider a new float and needle, then set it properly and try leaning out your low speed needle very slowly at a slow slow idle until it spits at you. Then open it up just enough to avoid the "spitting". Make sure that if the cowling insulation is still there, it is not hanging loose around the downdraft carb intake. If it is breaking down from age and fuel vapors, then remove all of it and thoroughly clean interior of powerhead cavity.
 
timguy,

This motor just had a full Carb Kit put in it as part of the restoration. It was done my a trusted mechanic, but if the consensus is to reset the float level, I'll check that.

Ah, my mistake - it's indeed a 1966!

And I do not have the original tank. OEM plastic aftermarket.

CMOS
 
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