Johnson late 80's v4 charge at idle?

[xxturbowesxx]

Just curious if those who own these motors know if they put out enough amps at idle to move the voltage levels?

The specific motor is a 1989 V4 140 Johnson.

I am having trouble with my tach and suspect a bad rectifier. I honestly haven't paid much attention to full throttle/on plane(mostly dodging sportfishers and screaming like a girl) but I did notice it in the 15v range while cruising last weekend(could have been briefly).

Voltage levels remain around 12.5v at idle FWIW.

Thanks in advance guys

 

[emdsapmgr]

Re: Johnson late 80's v4 charge at idle?

Your engine does not have a rectifier. It has the upgraded combination rectifier/regulator. (It's much more expensive.) Usually tach issues are as a result of a problem with the rectifier/regulator, so you do have a credible question. In your case, it seems that your normal battery voltage is about right. (12.5) Also, when running, the volts seem to indicate that it is charging properly. I'd think that after just starting, the voltage might be in the 12.1 volts, gradually increasing to maybe to 13-14v figure after planing for 15-20 minutes. Possible it goes to 15 briefly, then may drop back to 13-14v with the internal regulator feature. Keep in mind that most boat voltmeters work through the wiring within the boat. It is likely there is a minor voltage drop (maybe a volt or so) from what is actually going on right at the battery.

 

[JDusza]

Re: Johnson late 80's v4 charge at idle?

IMHO
At idle you may not see the battery charging. You might need to get rpm up to about 1200 (?).
12.5 at idle sounds good in that you are not draining (<12v). At idle you are "maintaining" the battery....not charging it much.
At 15 v, I think that's a little high and if there's a way to adjust the regulator, you might want to bring that to 14 or a little under.
J

 

[xxturbowesxx]

Re: Johnson late 80's v4 charge at idle?

IMHO
At idle you may not see the battery charging. You might need to get rpm up to about 1200 (?).
12.5 at idle sounds good in that you are not draining (<12v). At idle you are "maintaining" the battery....not charging it much.
At 15 v, I think that's a little high and if there's a way to adjust the regulator, you might want to bring that to 14 or a little under.
J

The battery shows a good voltage because I charge it almost everytime I go out to be on the safe side. I will be going out tomorrow and will pay closer attention.

 

[coolbri70]

Re: Johnson late 80's v4 charge at idle?

how long does it take to top off when you are done boating? i have an automatic charger, if i dont leave on a radio or something on the way home, only takes less than a minute to read full and shut off. this is with my 85hp v4 crossflow

 

[emdsapmgr]

Re: Johnson late 80's v4 charge at idle?

What tach issues are you experiencing?

 

[xxturbowesxx]

Re: Johnson late 80's v4 charge at idle?

how long does it take to top off when you are done boating? i have an automatic charger, if i dont leave on a radio or something on the way home, only takes less than a minute to read full and shut off. this is with my 85hp v4 crossflow

More than that.. Hard to say though. I only charge at 5 amps and have a 31series deep cell so it takes awhile.

What tach issues are you experiencing?

It reads like a broken clock... Doesn't


I brought 2 batteries for comfort and hooked up my accessories(including my voltmeter) on the backup battery.. Learned nothing from this trip.

 

[emdsapmgr]

Re: Johnson late 80's v4 charge at idle?

Possible the tach is not getting a signal. I'd do a continuity test on the grey (signal) wire from the tach back to the terminal board on the starboard side of the engine. I had one that developed an "open" in a 1978 control box harness. Or just temporarily run a secondary wire over the seats in the boat as a test.

 

[coolbri70]

Re: Johnson late 80's v4 charge at idle?

More than that.. Hard to say though. I only charge at 5 amps and have a 31series deep cell so it takes awhile.



I charge at 6 amps, and the last thing before i take it out of the water is idle for an hour sometimes waiting for the ramp to clear up. so i would think if yours is taking a long time to top off, the either the system may be overloaded, not charging, or a bad battery