Voltages for a 28hp Johnson

[waterinthefuel]

Hi guys, this is my first post on this forum. I have a 1993 28hp outboard. At idle, I only get 12.1 or 12.2 volts at the battery. When running at about 2-2.5k rpm, it only goes up to about 12.5. This voltage was checked with a digital voltmeter, not some unreliable onboard gadget. My fathers two larger outboards (Mariner 125 and Evinrude 150xp) both put out around 13.5 at cruise, and almost that at idle. I understand my little motor is probably unregulated, but is this voltage a little low to keep the battery charged? The engine runs like a clock and has given absolutly no trouble except for one very minor fuel leak problem. Any help would be appreciated.<br /><br />Brandon

 

[waterinthefuel]

Re: Voltages for a 28hp Johnson

bump

 

[waterinthefuel]

Re: Voltages for a 28hp Johnson

bump

 

[G DANE]

Re: Voltages for a 28hp Johnson

How old is your battery and how often do you use your boat ? As batteries tend to get older, they require more and more charging before volts are all up. A battery that is a bit tired will absorb upper volts for some time, most of a 3/4 hours trip. Try to charge your battery first with a stationary charger and then see what your get. Of coarse your charge coil could be going bad, but rarely seen.

 

[waterinthefuel]

Re: Voltages for a 28hp Johnson

My battery is getting old. I'd say 3 or 4 years. I brought it home to get it refurbished. I will do what you said, that's kinda the line I was thinking. I know if you have a very dead battery it will suck up the volts until it's charged, but it isn't that dead. I'll see. I appreciate your reply. I was getting worried! LOL

 

[rickdb1boat]

Re: Voltages for a 28hp Johnson

Measure it at full throttle if you can. I think you will find the results much different. What you posted, sounds right. I have an 89' 28 HP and the readings are about the same.

 

[R.Johnson]

Re: Voltages for a 28hp Johnson

Most multimeters will read to 10 amps. Connect an amp meter in series with the red wire coming from the rectifier, going to the starter solinoid. It should read 4 amps at WOT, if so, your charging system is OK. This will give you a more accurate reading of what is going on.

 

[rickdb1boat]

Re: Voltages for a 28hp Johnson

Yeah, I also checked mine with a clamp-on meter and got about 4 Amps at WOT.

 

[Xcusme]

Re: Voltages for a 28hp Johnson

Rick,<br />Not to nit-pick but, I think you ment to say 4 AMPS right?? Just to clarify, so nobody gets confused by the volt/amp thing...

 

[rickdb1boat]

Re: Voltages for a 28hp Johnson

Yes, you are correct. 4 AMPS Thanks,

 

[waterinthefuel]

Re: Voltages for a 28hp Johnson

Well guys I appreciate the help. That amp thing sounds like a fantastic idea. Thank you and I'll post the results as soon as I can get my hands on the boat again. (It's at a fishing camp.)