tachometer for Johnson Super Seahorse 33hp

[jdsgrog]

I have a '67 johnson super seahorse 33hp motor. I was wondering if there is a tachometer that is compatible with this motor. Looking at other threads, I cannot find anything about installing tachs on older motors. My motor does not have a generator.

 

[Chris1956]

Re: tachometer for Johnson Super Seahorse 33hp

OMC used to make a special tach for that motor. It ran off of the killer wire on the points. You could borrow and try a shop dwell/tach in the 4 cylinder seting. If it works you can buy an automotive-style tach with a 4 cylinder setting.

 

[jdsgrog]

Re: tachometer for Johnson Super Seahorse 33hp

thanks for the quick post. i'll try your suggestion and see if it will work.

 

[F_R]

Re: tachometer for Johnson Super Seahorse 33hp

As you probably have already figured out, today's tachs get their signal from the alternator, and you don't have one, nor can you get one for that motor.

An old four cylinder/4-stroke automotive engine with points ignition fires two times per crankshaft revolution. An outboard such as yours has separate points for each cylinder and the points break one time per revolution. I'd be surprised if you find an automotive tach that works, other than a tach/dwell test instrument.

An exception would be one that takes it's signal from a spark plug wire, and even then it would have to have a two-stroke setting because it fires twice as often as a four-stroke.

Most people are using Tiny-Tachs on those motors. They get a signal from a plug wire. Not that I think they are pleasing to the eye. Google tiny tach.

Or keep an eye on e-bay for the right OMC tach.

 

[jdsgrog]

Re: tachometer for Johnson Super Seahorse 33hp

yes, i figured that. i think i'll look into the tiny tach. as much as it'd be best to get something that looks aesthetically good, i need it more for functionality at this point. thanks for the help.