'91 88SPL johnson tachometer quit working while running. how can I test it?

[toddschubert]

Tach quit while running and I happened to be looking right at it. Just fell to "0". Motor runs fine.
I don't find any loose wires and I re tightened the ones at the tach.
My Seloc manual (which sucks by the way) does not have a diagram showing which wires at motor are associated with the tach. I assume they would be on the power pack harness but not sure.
How do I test for where the problem lies? is it a bad tach or missing signal?
Thanks for any ideas!

 

[Bosunsmate]

Re: '91 88SPL johnson tachometer quit working while running. how can I test it?

It connects to the terminal block.
It has three wires coming off it normally. Look for two yellow wires and a red. It shouldnt connect to the powerpack
The grey it connects to on the termoinal block is the wire to the tach that takes the signal.
Search on this site for rectifier test and itl come up. You basically check that each wire has contunity in one direction but not the other.
Also check the stator is putting out charging voltage ac as that is what the rectifier and thus tach works off too

 

[toddschubert]

Re: '91 88SPL johnson tachometer quit working while running. how can I test it?

My rectifier has been acting up...sometimes not charging system. It may be bad I guess that would make tach not work

 

[Daviet]

Re: '91 88SPL johnson tachometer quit working while running. how can I test it?

Correct, a defective rectifier will cause the charging system not to charge the battery.

 

[toddschubert]

Re: '91 88SPL johnson tachometer quit working while running. how can I test it?

would the tach not work if the rectifier is not working or removed?
I have found a broken wire at base of rectifier (red) and it seems to test bad. It was also leaking brown insulation oil.
I ordered a new rectifier that hopefully will be here by the weekend. I put all other wires back in place and cranked engine and the tach does not work. I hope it does need the rectifier to work
I measured voltage coming from charge coil and it is 25 tod 55 volts but DC my meter says. I thought it would be AC

 

[V153]

Re: '91 88SPL johnson tachometer quit working while running. how can I test it?

would the tach not work if the rectifier is not working or removed?

Absolutely! A bad rectifier will definitely cause problems with the tach. Been there.