Tiny Tach Accuracy

[ehenry]

I finally was able to get my boat in the water this weekend and test repitched prop and also to see how my new Tiny Tach worked. I'm really pleased with the prop. It got the boat out of the water and on plane just like I want it to. The Tiny Tach worked well too. My question is, How accruate is it? My engine is a 1999 Merc 25 h.p. 2 stroke. I know WOT is 5500 to 6000. The highest RPM shown on my run was 5400. The prop was pitched down from 13 to 11. My boat is a 14 foot flat bottom .

 

[Big Al1]

Re: Tiny Tach Accuracy

Supposed to be very accurate. Works off of the plug wire’s inductance. So there is no analog converting to rpm readout. It is the actual number of sparks. Each spark results in a revolution of the crank shaft. Mine reads up to 5960 on my 15hp Merc on a light 14ft jon boat. You may need to reprop again.

 

[ehenry]

Re: Tiny Tach Accuracy

I think I'm going to look in the air silencer box just to make sure my throttle plate is opening all the way. Nothing has changed other than going down in pitch.