temporarily hooking up tach to 6 hp

[bob johnson]

I have an extra dash mounted tempo tach...

I d like to hook it up temporarily to check the rpms of some of my smaller motors on various boats I have to see what rpms the motor is turning while i diagnose tune up and prop selection.

on the back of the big tempo tach is

send
ground
ignition
light

I aslo have selctable P and C positions

it actually says on the back how to wire a few setups..but not mine

wire connections:
gnd-ground
ign-14 volts d/c ignition
lt-lamp
send: 4 cycle-neg side of coil
O/B with AL(cant read last one or two letters but it isn t a T)- alternator

and it has a slot on the back for calibrating the tach

my outboards are 2 strokes, and they DONT have alternators!!!!

how do i wire this tach inot my 1969 evinrude 6 hp and my 1990 johnson 15 hp

thanks

bob

 

[wilde1j]

Re: temporarily hooking up tach to 6 hp

Don't think that tach will work. I'd get a Tiny Tach ... very easy install and doesn't need any DC source to work.

 

[CATransplant]

Tach for 2-stroke small outboards

Tach for 2-stroke small outboards

I found a handheld tach last year with an inductive pickup and settings for both 2 and 4 stroke engines. It clips to a 12 V source, and the pickup goes on a spark plug wire.

It works great for diagnostic purposes and for checking WOT RPM, and will work on any darned engine you can find. I checked my lawnmower with it and hooked it up to my V6 truck and my Volvo. It gave accurate readings on all of them.

The trouble is that it was made in the 1980s, and I can't find anything like it with the 2-stroke settings. You can use a 4-stroke inductive pickup tach, but you have to double the readings for a 2-stroke. Not much chance of finding a tach that reads to 12,000 RPM, so that's useless.

I'm still looking, but I've got mine, so I'm good. If you want one, keep checking ebay for a Suntune CP 7602 Inductive Tachometer. It has to be that exact model. Later models didn't have the 2-stroke/4-stroke switch, and are useless for 2-stroke outboards.

I got mine in a thrift store for $4. The last one I saw on ebay was going for about $25. It'd be worth it, too.

 

[RSchendel]

Suntune CP7602 portable tach

Suntune CP7602 portable tach

I just purchased one of these Suntune CP7602 units on Ebay. It is perfect cosmetically, but I am suspicious of the accuracy. The low RPM setting shows about 800 RPM, but the High RPM setting shows about 2000 RPM. I do have it on 2 cycle mode and then inductive clip is the right direction on the top spark plug wire.

Any thoughts if someone has experience with this same unit?

I am trying this on an Evinrude 15024 18HP from 1958.