1967 Merc 650 - What is the correct type of Tachometer 8p or 12p?

[tgp***]

I was reading some threads on this, but I am confused as to which tpye of tach would be correct w/ the thunderbolt ignition on my motor. Is it an 8 pole or 12 pole??

I have a 15 pitch prop on the motor now (16 foot aluminum boat). It test drove out great, it jumps up on plane and flies. I picked up a second motor (same year), for spare parts. It came with a 19 pitch prop, thats in really good shape.

The 15 pitch should be touched up. I have no speedometer, nor do care. I just don't want to wreck the motor, so a tach may be required.

thanks

 

[redjmp]

Re: 1967 Merc 650 - What is the correct type of Tachometer 8p or 12p?

Well I had a 1965 65hp and while its been a while since I sold that motor, I think I remember the stator having 12 poles and since none of them are used as trigger since the motor has a magneto ignition with a distributor, I think you need to set the switch on your tach to 12.
Or was it 6?...

 

[tgp***]

Re: 1967 Merc 650 - What is the correct type of Tachometer 8p or 12p?

I think you need to set the switch on your tach to 12. Or was it 6?...

I have no idea......I hope to find out, I would'nt mind finding a tach that I could mount on top the dash as opposed to in the dash. Need to figure the correct type first. Then I can try to find one....

 

[tgp***]

Re: 1967 Merc 650 - Tachometer help?

Re: 1967 Merc 650 - Tachometer help?

Trying to get a tachometer to work on my Merc. I picked up a NOS Faria Tach on ebay. There a 6 settings on the back of the unit 1-6, I'm geussing they correspond to 4, 6, 8, 10, 12, and 20 pole settings (can anyone verify that??). No info on the Faria site because they no loner make 20 pole Tachs. Not sure either on the correct number of poles for my motor, but I believe it to be a 12 pole.

The following is a quote from a reply to a post by Chris1956
""Re: Tachometer for '72 1150
Most any aftermarket OB tach will work on that motor. You need to look to see if there is a brown wire on the switchbox, on the non distributor side. That is the tach signal wire and it is set up for the old Merc tachs, which no longer exist(or are hard to get). If so, that needs to move and connect ro one of the yellow stator wires, at the rectifier.""

Will this work on my 1967 Merc 650??

Thanks in advance

Attached photo of wire diagram