which tiny tach??

[Absolutbost]

Which model tiny tach do i need to use to check rpms on a johnson 9,9?? the 2c is used on engines with one spark firing on each revolution of the crankshaft, or on 2 cylinder engines where the cylinders fire 1X per revolution. Is that the one I need? also is there some other way to check the rpms?? thanks for your help

 

[Paul Moir]

Re: which tiny tach??

I strongly suggest you phone them and ask. They don't provide the information on their website, but for some outboard models they put on a little snubber and give it a different part number. From what I've heard, they're slow to respond to emails.
But yes, your engine fires each spark plug once per revolution, and it'll be based on the 2c tach.

Another way to test RPMS is with a laser tachometer. These are getting pretty cheap, but it's hard to use one and steer the boat at the same time sometimes. You also have to operate with the cowl off.
Good for other stuff though.