1980 Mercury 40 hp outboard tach problem

[YN2(SS)]

I have been working on this outboard and the tach was not operating when I first got the outboard running. The electrical system was not charging the batter and I found a bad regulator/rectifier. I replaced that and now the tach is doing this. When I pulled the wiring harness plug out of the from of the remote control, I found some corrosion on the grey tach wire hole, and have not had a chance to correct this yet and test it. Any other thoughts?

http://www.youtube.com/watch?v=8KPzNgI7MxM

 

[YN2(SS)]

Re: 1980 Mercury 40 hp outboard tach problem

Has anyone seen this problem before or know where to start?

 

[petryshyn]

Re: 1980 Mercury 40 hp outboard tach problem

The stator may be failing.
Tach could be bad.

 

[YN2(SS)]

Re: 1980 Mercury 40 hp outboard tach problem

How would I test if the stator is failing (follow test in Seloc manual?/ I'm not seeing any other symtoms (i.e. o/b runs good, charges good, etc.))?

How would I test the tach?

If I need a new tach, what do I need to know to order one? Someone said I need to know the number of poles on the stator. I believe I counted 10. Is that all?

 

[YN2(SS)]

Re: 1980 Mercury 40 hp outboard tach problem

As a follow up, this tach problem has been there from the beginning of getting the boat in the water, and now I have a new problem which I am wondering if it may be related. See thread

http://forums.iboats.com/showthread.php?t=355455

I guess I need to man up and figure out how to accurately test my:
tach
stator
switchbox

Any suggestions?