1963 johnson 18 Motor runs on ears fine, stalls in water?

I have a 1963 Johnson sea horse 18 hp it is new to me this year. I put it on and ran it on the ears in my yard. it started, idled good, and reved fine, didn't rev it to high. I engaged the gear, forward and reverse, sounded good. i couldn't believe how well it ran. The fuel mixture is 40:1

I launched the boat, it started on the choke and would idle fine, even after putting choke in, but only when the cold start lever on the throttle was pulled up all the way, for added fuel. when i put the lever down, it started idling low, I tried to engage it into reverse and it died. Everytime i tried starting after that it would stall when i tried to engage it into gear. Eventually it only started with starting fluid and would only run for 10 seconds or so? Now it won't start at all?
can't tell whether it is a fuel problem? spark? lack of fuel, or too much fuel?

Re: 1963 johnson 18 Motor runs on ears fine, stalls in water?

Howdy,

Welcome to iboats.

The link 'n' synch must be done with the exhaust in water so it gets back pressure. Your engine sounds like it was tuned up without back pressure.

Re: 1963 johnson 18 Motor runs on ears fine, stalls in water?

I have some questions. I don't beleave the control box for a 1963 engine has a cold start lever. On a 1963 engine your fuel mix should be 24:1. NEVER use starting fluid on your engine. How did you install muffs on your engine. Could you post your model number, maybe I am wrong and would like to look up your engine.

Re: 1963 johnson 18 Motor runs on ears fine, stalls in water?

Did you rebuild the carb?
It's possible that the passages are plugged or its it been a very long time since it's been rebuilt the float could be make out of cork and no good.

Re: 1963 johnson 18 Motor runs on ears fine, stalls in water?

Thanks for all of the replies, much appreciated.
I have to unscrew a small plate in order for the ears to work, as this motor wasn't built with ears in mind.
The control box isn't a 1963.
The guy at the boat place told me to run it 50:1 despite it being recommended 24;1, he said with the newer synthetic oil you don't mix it 24:1
I think it must be the carb, took it out again last night and the only way it would start was with the motor kicked up out of the water. it would rev fine, but as soon as i dropped the motor down it would only, barely run, with the choke on?

Re: 1963 johnson 18 Motor runs on ears fine, stalls in water?

I wouldn't really run it out of the water, but pull that carb apart again. I can't see it being anything else as those old outboards were very simple. If you have good spark and the timing is right then it has to be the carb.
O and 24:1 is doesn't matter what oil but 24:1 or your wasting time making sure it runs well because you'll burn those solid bearings.

Re: 1963 johnson 18 Motor runs on ears fine, stalls in water?

JB said:

Howdy,

Welcome to iboats.

The link 'n' synch must be done with the exhaust in water so it gets back pressure. Your engine sounds like it was tuned up without back pressure.

Click to expand...

Sounds like the most logical reason other then the carb.