Tachometer issues maybe bad R/R.

[akapolas]

Hey all!!!

I got another issue. I have a 1990, 200HP Johnson outboard that I just bought and i'm having a problem with the Techometer and probobly the rectifier/regulator.
I was told to test the battery volts while the engine was running and while it's off and the voltage stays the same, so does that mean i got a bad R/R?
I tried to locate the R/R but I'm not sure if I'm looking at the right part. Right on top of the engine directly behind the flywheel there is a cover that looks like a battery pack when I remove it there are a whole bunch of wires and what I think is the R/R, am I correct?
When I removed the cover (what looks like a battery pack) i saw one tan wire that was not conected. Could that be the tach problem? if so where does it get connected?
You guys are the BEST, thank you in advance.

 

[ezeke]

Re: Tachometer issues maybe bad R/R.

Just behind the flywheel is the powerpack, and under it is the regulated rectifier.

Tan wires are for the warning systems and have nothing directly to do with the rectifier, tachometer or charging system.

 

[akapolas]

Re: Tachometer issues maybe bad R/R.

So if the battery voltage is not changing with the engine off and with the engine on, whould that mean it's a bad r/r?

Should I attempt to swap it out my self?

 

[Joe Reeves]

Re: Tachometer issues maybe bad R/R.

(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).

A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging system, and the tachometer simply doesn't register.

However.... those water cooled regulator/rectifiers that are used on the 35 ampere charging systems (and some others) bring into play a different type problem, and as you've probably found out, they are really a pain to troubleshoot via the proper procedure. There's an easier way.

The tachometer sending/receiving setup operates off of the gray wire at the tachometer. That same gray wire exists at the engine wiring harness which is connected to the engine electrical terminal strip. You'll see that there is a gray wire leading from the regulator/rectifier to that terminal strip, and that there is another gray wire attached to it. That other gray wire is the wire leading to the tachometer which is the one you're looking for.

Remove that gray wire that leads to the tachometer. Now, find the two (2) yellow wires leading from the stator to that terminal strip. Hopefully one of them is either yellow/gray or is connected to a yellow/gray wire at the terminal strip. If so, connect the gray wire you removed previously to that yellow/gray terminal. Start the engine and check the tachometers operation, and if the tachometer operates as it should, then the regulator/rectifier is faulty and will require replacing. If the tachometer is still faulty, replace the tachometer.

If neither of the yellow wires from the stator is yellow/gray, and neither is attached to a yellow/gray wire, then attach that gray tachometer wire to either yellow stator wire, then the other yellow wire, checking the tachometer operation on both connections.

I've found this method to be a quick and efficient way of finding out which component is faulty.... the tachometer or the regulator/rectifier. It sounds drawn out but really only takes a very short time to run through. If the water cooled regulator/rectifier proves to be faulty, don't put off replacing it as they have been known to catch on fire with disastrous consequences.

 

[ezeke]

Re: Tachometer issues maybe bad R/R.

Take digital pictures of each step, use your factory service manual and sure, you can change it yourself.

You will never find a better mentor than Mr. Reeves, so be sure to follow any advice that he gives precisely.

 

[akapolas]

Re: Tachometer issues maybe bad R/R.

Sorry I didn't reply earlier, but I'll like to add a resolution to the post in case anyone is having the same problem.

I ended up changing the R/R and all is good.

Thanks for all your help.