1996 18 CC with original 115 Yamaha 2 stroke charging problems

[james sullivan]

Good morning All, have a basically all original 1996 18 CC with the original 115 Yamaha. It seems to have developed a "lack of charging volts" issue. I monitor the running volts off a Simrad and when idling it shows anywhere from 11.4-11.6 V, slightly higher when underway, but still very low and appears to slowly drain the batteries. I did replace the rectifier last year as a precautionary/maintenance measure and used an OEM Yamaha part for that. Maybe time for an alternator.? Stator.? or should I check something else before throwing $$ down that hole. Thx in advace for the help

 

[Puck-n-Fish]

First and cheapest, check all your wires and connections for corrosion. On a boat that old it could be something as simple as that. Most of us with those older models have gone through all our wiring and you'd be surprised at what you find. One of the electrical experts here can help with the motor charging if your wiring is tight.

 

[pelagic2530]

Where are you measuring the voltage?

A functioning alternator should be putting out from 13.8-14.5v. If you’re seeing 11v at the battery connections, you’re definitely not getting the charging voltage you should be.

 

[tomc585]

Don't overlook the obvious.
Clean, clean and clean all your cable connections.
Even if they look clean from the eye.
Then measure from the output at the motor and work towards the batteries and console.
Also make sure it's all secure.
It's such a simple and effective system you should have it figured out in no time.