Merc. Tach

[croSSed]

I have a 1987 115 T.O.P. My tach is not a Mercury tach, I believe it is a Marpac or Teleflex. Anyway, I think the tach is not acurately measuring rpm. Is there a way to test it? Also, do one of these In-line 6's (the late model ones) have a rev limiter? Thanks!

TG

 

[ricksrster]

Re: Merc. Tach

Make sure the little switch on the back of the tach is set at 12 pole or 6 pulse.

 

[croSSed]

Re: Merc. Tach

rickster, thanks for the reply. It is set properly. Here's what I mean. I recently added a jack plate to my boat. I am using a 22p Laser II. According to the tach, after I added the jack plate, the motor is turning about 6000 rpm. Trouble is, the sound of the motor, the pitch, i.e., the "note", it is giving me at full speed, and the way it sounds "stressed", it sounds like it is turning up more than that. Sounds like it is screaming! I'd say, by the sound, it's turning up closer to 6400.

TG

 

[ricksrster]

Re: Merc. Tach

You can try using another tach to see what you read.

 

[hkeiner]

Re: Merc. Tach

I recently bought a cheap used handheld tachometer on ebay. The tach connects to a spark plug wire with an induction connection. I used it to confirm the RPMs on my dashboard tach gauge (at higher RPM levels) and to precisely set the low idle RPMs on the motor when doing a link and sync. I thought it was a good tool to get. You might consider doing the same.