How to stop a 1957 Johnson seahorse

[gazelle]

I recently purchased a small aluminum boat that has a 1957 Johnson Seahorse 18 hp engine. The motor runs like a top. The three times that I have started it, the engine has only taken two pulls to start. My problem is that when I adjust the throttle to stop nothing happens. The previous owner said that he just pulls the choke out and pushes it back in to stop it. His solution is not really reliable since it takes a couple of minutes doing this before it will actually stall the engine. <br /><br />On the control arm someone at one time put a modern day rubber grip on it. The marking on the grip does not line up with the writing on the control arm. I was wondering if when whoever put the new grip on if they just simply hooked it up wrong. I am not sure of what the stop position is suppose to do to kill the engine. Any suggestions on where to start so that I can stop the engine?

 

[JB]

Re: How to stop a 1957 Johnson seahorse

Hi, Gazelle.<br /><br />Welcome to the board.<br /><br />There should be a kill button on the end of the tiller or mounted on the front of the case to stop your engine. It is a simple push button that when pushed grounds the points in the magneto.<br /><br />An alternate way to stop your engine is to disconnect the fuel line and let it run out of gas. This is a bit risky, because it runs the risk of denying the engine lubrication, but it has been done for many years and rarely, if ever, causes a problem.<br /><br />The fuel ratio for your engine is 24:1. One quart of TCW-3 outboard oil to 6 gallons of unleaded regular.<br /><br />Good luck.

 

[Chinewalker]

Re: How to stop a 1957 Johnson seahorse

Sorry JB, there was no kill button on a 1957 Johnson 18hp - at least not from the factory. It is relatively easy to hook one into the points if needed by drilling a hole into the bottom of the armature plate and running two wires - one to each set of points. The other ends of the wires go to a kill switch that is a closed circuite when triggered.<br /><br />On the other hand, the tiller handle ought to stall the motor by turning it all the way down to the physical stop, not just the word "stop". I've never had a '50s Johnrude that wouldn't stall out when slowed down all the way - that's why there's a stop position marked on the throttle arm plate (although motor speed and arrow position in relation to the plate seldom matched perfectly). Later motors had the nylon adjustment screw in the throttle pinion gear which could adjust the minimum slow position. Perhaps this motor has been retrofitted with one of these and needs it adjusted/removed to achieve full stop?<br /><br />- Scott

 

[gazelle]

Re: How to stop a 1957 Johnson seahorse

Chinewalker<br /><br />I have turned it all the way down to the stop (not just where it is written) Think it could be that the idle speed is set too high so that backing off the throttle does not stall it? To be honest I have not taken a real close look because I have been so busy with work lately.

 

[bhalsdorf]

Re: How to stop a 1957 Johnson seahorse

My 1958 Johnson 35 uses mercury switches to ground out the magneto when turned to stop position. If yours does also it will be located inside attached to the throttle rod by the gear. It looks like 2 small cans next to each other about 1/4" in diameter and about 1/2" long with wires going to bottom. These could be bad or not adjusted properly.

 

[rolmops]

Re: How to stop a 1957 Johnson seahorse

For what it is worth.<br />With my "electric" '57 there is a little button on the dash that says "push choke to stop" under it.This seems to be the way this engine is supposed to be stopped.The '57 still has the 5 prong quick connector.On the '58 there are already 6 prongs and that 6th one would be going to the magneto and therefore be the switch off.

 

[Yepblaze]

Re: How to stop a 1957 Johnson seahorse

On my 58 Johnson 18hp. I was also amazed by the fact that there is no kill switch. I did put a small rubber snubber (small precicely cut to lenth piece of fuel line) on the end of the throttle stop screw on the side of the motor. If I twist real hard towards the stop direction eventually the mag plate will come around and stop the motor.<br /><br />I have since used the choke to stop it without problems.