Electrical/charging/gauge issue

captmello

Captain
Joined
Jun 30, 2008
Messages
3,845
I'm not sure if this is an electrical issue, or an outboard motor issue, but I'll post it here.

I'm dealing with my Pontoon Boat, Its a 1996 model with a 2001 Johnson 2 stroke 90hp, 60 deg, looper with VRO.

the last couple times out I've noticed an issue that doesn't happen all the time, but seems to be happening more commonly the more I use the boat.

roughly every 3 times I start the boat, warm or cold, the Tach will behave oddly. It will show a steady display at idle, but as I increase the throttle, it starts jumping up and down between 500-1500 rpm and then drops to zero as i speed up. If i drop back to idle speed the tach will read normally until I increase the throttle when it will flutter then drop to zero. Along with this, when this is happening, the Voltage will read low, between 12 and 13 volts, It normally reads about 14 when the engine is running over 1500rpm. So, then, if I continue to cruise along, within a minute or two, the tach and voltage will both jump up to normal readings for the remainder of that run cycle. I could stop, turn off the motor and restart and it may or may not happen again.

Now, sometimes, the tach will seem to work fine with no fluttering, but the voltage appears to be slow to come up to its norm of 14 volts. It will eventually make it to 14V, but slower than "normal"

All the gauges are fairly new. the volt gauge is roughly 5 years old and I replaced to tach last summer.

So I'm hoping I can get some tips on solving this issue. Naturally, the boat is 4 hours away, but I hope to have a few items to check next time I'm at the boat to try and narrow down the problem.

Thanks!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,843
The tach is driven off the voltage regulator. So it is either the tach itself, the wiring between the VR and Tach or the VR itself.

You can disconnect the tach wire at the VR and the gauge and put an ohmmeter on it to ground. Any resistance below infinite means that wire is grounding somewhere.

There is no test for the tach, except comparing it to a known good tach.

The voltage regulator could be failing. It should be available aftermarket. They are not hard to install.
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,604
Check all the ground connections first, from the battery to everywhere it goes. Make sure they are clean to bright shiny metal. Then see if you still have the same problems...JMHO
 

captmello

Captain
Joined
Jun 30, 2008
Messages
3,845
The tach is driven off the voltage regulator. So it is either the tach itself, the wiring between the VR and Tach or the VR itself.

You can disconnect the tach wire at the VR and the gauge and put an ohmmeter on it to ground. Any resistance below infinite means that wire is grounding somewhere.

There is no test for the tach, except comparing it to a known good tach.

The voltage regulator could be failing. It should be available aftermarket. They are not hard to install.

Can you confirm that this is the voltage regulator? #46 in the link
http://ww2.iboats.com/Ignition-System/dm/cart_id.491140584--session_id.342077687--view_id.1534891
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,843
That is a water cooled voltage regulator. Is it the one for your motor, I don't know.

You should look it up by year, model and HP on a site like Crowleymarine.
 

captmello

Captain
Joined
Jun 30, 2008
Messages
3,845
That is a water cooled voltage regulator. Is it the one for your motor, I don't know.

You should look it up by year, model and HP on a site like Crowleymarine.

Thank you so much Chris! That is the correct part, I just wanted to confirm with you that i was on the right track. The aftermarket parts were marginally cheaper so I went with the oem. Next time I am at the boat I will test the wire from the tach to the regulator to see if its grounging out. but I will also be armed with the new regulator. The Tach is only a year old so I'm hoping it is good.
Thanks again for helping me and folks like me, trying to keep boating and doing our own repairs! I'll report back with my results asap.
 
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