possible to hookup tach that does not have setting for 20 pole?

[mrdjflores]

1986 85hp

Is it possible to hook up a tach that does not have a setting for 20 pole alt. ??

haveing a difficult time with find a 20 pole tach that i like

 

[pnwboat]

Re: possible to hookup tach that does not have setting for 20 pole?

You can hook one up that is not for a 20 pole stator but it will not read the correct RPM.

In order to read the correct RPM, it has to be set up for a 20 pole stator.

 

[john from md]

Re: possible to hookup tach that does not have setting for 20 pole?

Or you can purchase a tinytach with enough wire to go from the helm to the engine. These are small but are easier to get than 20 pole tachs.

John

 

[sho3boater]

Re: possible to hookup tach that does not have setting for 20 pole?

Just watch ebay for a while is what I did, but the economy has that place pretty dead in some areas right now.

I was using a digital clamp on tach, but real pain to use on the water and they want to get confused by other wires. Have to add a long wire to get it away from the rest. No other tach will work.

 

[mrdjflores]

Re: possible to hookup tach that does not have setting for 20 pole?

if a 20 pole alternator spins 1000 times...you would have 20,000 pulses (every 20 pulses is one revolution) correct???

if you send these 20,000 pulses to a 10 pole tachometer...the tachometer would 'think' you are turning 2000 rpms (10 pulses per revolution)...correct ???

my thinking....take a 10 pole tach...remove the face...scan into computer...renumber the scanned image...and print out on vinyl label...take new label and stick it to the original tach face...then reassemble the tach

sounds like it should work...but have a feeling i'm missing something

your thoughts ??

 

[pnwboat]

Re: possible to hookup tach that does not have setting for 20 pole?

Yes in theory it would work. 10 pole tach would read twice the actual RPM's. Seems like a lot of work. Unfortunately I have never seen a 10 pole tach. They're usually 6, 8, 12, or 20 pole.

Most tachs are not easily taken apart without doing some damage, either cosmetic or mechanical.

 

[sho3boater]

Re: possible to hookup tach that does not have setting for 20 pole?

I forget but I'm sure I paid under $50 for my new one possibly under $40, shipped. Or you can look for a used one at a local dealer, yard, or online.

 

[mrdjflores]

Re: possible to hookup tach that does not have setting for 20 pole?

i have found some 20 pole tachs online...but they don't match my other gauges.
there seems to be alot more variety in the 10 pole tachs.
i think my other boat's tach had a setting on the back for 10 pole (4,6 or 8 cyl..10 pole or 12 pole) i may play with that and see how it does

 

[further]

Re: possible to hookup tach that does not have setting for 20 pole?

Tiny tach is the way to go. Easy to install and very accurate/reliable. I installed one just to confirm that my stock tach was giving me the correct reading. It also gives you hours.

 

[chitownborn]

Re: possible to hookup tach that does not have setting for 20 pole?

the tiny tach is one option, the only other one i know of is the red international tach made by tele flex, thats the only two i know of

 

[timbecht]

Re: possible to hookup tach that does not have setting for 20 pole?

where can i find the tiny tach post link please

 

[further]

Re: possible to hookup tach that does not have setting for 20 pole?

http://www.tinytach.com/tinytach/index.php

Call them to order to make sure you order the correct one for you motor.

 

[poor_boy67]

Re: possible to hookup tach that does not have setting for 20 pole?

Not that it would match your other guages but I just bought a 20 pole tach off ebay that come real close to matching my guages that were in my Champion boat for $26 made by Stewart Warner and it works very good.
The guy had like 20 more....