High Voltage on Johnson60

[NZ-Kevin]

I have a 1986 Johnson 60hp, AJ60TLCDS, and it is charging at too high a voltage. Everything was working fine but I fitted a new radio, which showed a high voltage error when the engine was running. So I bought and fitted a volt meter to check. Just taken the boat out for a run and it's running at about 17v, which is obviously too high. I don't have a wiring diagram, is there a voltage regulator in there that will need replacing or could there be another cause.

 

[Haffiman]

Re: High Voltage on Johnson60

At the present you only have a rectifier and no regulator. If running sensitive instruments, install the regulator used on the late 90's and up engines. You may regulate the voltage 'manually' by using an oversize old type lead-acid battery and turn on accessories like lights etc to keep the voltage down. Any sealed, AGM etc type battery will peak up your voltage with the present set-up.

 

[NZ-Kevin]

Re: High Voltage on Johnson60

Thanks, that explains why I couldn't find one when I looked at the engine. I thought it was hidden away somewhere. The battery should regulate things a bit, but it doesn't seem to be doing too good a job. I'll take a look for the later regulator, I presume if I look for a late 90's 60hp I shoud find it in the parts list. Anyone have a link for the circuit duagram of whwere it goes?

 

[NZ-Kevin]

Re: High Voltage on Johnson60

OK, found the later voltage regulator, it seems to be built in to the rectifier -which makes for a rather expensive unit. What sized battery should be on this motor? could too small a battery cause the high voltage (not big enough to regulate it), I do have a large marine battery spare -a Sea Master MFM70 but that specifies max charging voltage of 14.8V. Would the voltage be held down more buy this bigger battery? Sorry for all the questions, it's just offputting having the radio flash "voltage too high" at you when the engine is running.

 

[Haffiman]

Re: High Voltage on Johnson60

Give the battery a try. The only 'negative' result might be that the problem persists.