My Evinrude 70hp -89 is charging too high voltage

viktor_89

Cadet
Joined
May 17, 2011
Messages
22
Hello, When I am measuring the voltage on the battery without the engine running, I got 13V, but when I start the engine, the voltage slowly rises up until it reaches 18V!? I guess this is not good either for the battery or the engine itself.

Can it be the charge controller that has broken? Where on the engine is it, and does anybody know where I can get a new for a reasonable price?

By the way does anybody know which rpm the engine shell have as maximum?

Thanks in advance /Viktor
 

Nh1100

Recruit
Joined
May 17, 2011
Messages
1
Re: My Evinrude 70hp -89 is charging too high voltage

I am having a similar problem with the same motor however my voltage reads 15.2 at it's highest. Are you using a trusted voltmeter to measure?

As for rpm, I run at 5000 comfortably but wouldnt take it higher due to age and it's low compression (105 psi for all 3 cyl).

Once I take mine to a marine electrician this weekend I'll post the outcome.

Cheers
Nick
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
Re: My Evinrude 70hp -89 is charging too high voltage

don't know why your engines are charging that high but nh your compression is not that low. As long as the cylinders are within 10% of each other don't worry about it. If they get around 85-90 then you know that the rings are wearing out. Other than that run the dog poop out of it.
 
D

DJ

Guest
Re: My Evinrude 70hp -89 is charging too high voltage

It's an unregulated system. You may see spikes up to 16V. Normal.
 

eavega

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Joined
Apr 29, 2008
Messages
1,377
Re: My Evinrude 70hp -89 is charging too high voltage

It's an unregulated system. You may see spikes up to 16V. Normal.

I was gonna ask if that was an unregulated system. I have a '76 70 HP Johnson which is unregulated. It too can get up to 18v. I was trying to cut down weight on my boat, and switched from a 29HM Marine Battery (dual use battery) to just a small starting battery. While the smaller battery never failed me, I noticed that the charging system was reading 18v at WOT, as opposed to about 15v with the Marine battery. I guess the bigger battery acts as some kind of voltage sink that does not allow the charging system to get higher than 15v. You'll have to ask someone more knowledgeable about DC voltage why that happens. I only know its a fact that the larger battery helped regulate the charging circuit.

Rgds
 

Barnacle_Bill

Admiral
Joined
Feb 8, 2004
Messages
6,469
Re: My Evinrude 70hp -89 is charging too high voltage

Some reasons for high voltage is bad, loose or dirty battery connections. Bad or wrong type battery. You must use a marine battery.
 

patrick4266

Chief Petty Officer
Joined
Nov 29, 2007
Messages
591
Re: My Evinrude 70hp -89 is charging too high voltage

Mine also runs about 16 volts, will it overcharge the battery and burn it up?
 

viktor_89

Cadet
Joined
May 17, 2011
Messages
22
Re: My Evinrude 70hp -89 is charging too high voltage

Thanks for the answers!

Nick, looks forward to see the outcome of your visit at the electrician..

Are you sure there is an unregulated system?, I visited a boat workshop and asked for the price of the engines voltage regulator and they found a price of 613USD. I thought that was too expencive to chance if it would not help, so I decided to ask on the forum.

I don?t think the battery is the problem due to I have tested different ones with the same result. (Leisure batteries)
 

viktor_89

Cadet
Joined
May 17, 2011
Messages
22
Re: My Evinrude 70hp -89 is charging too high voltage

I have now cleaned the battery connections but without any success. The battery I use is a Volta 75 aH leisure battery.. I also tested to start the engine and then disconnect the battery and when I measured the voltage on the battery cables (whitout battery connected) I got 55V!?

Any more suggestions of what can be wrong? If there is an unregulated system, then what parametres do I have to play with to lower the voltage?

As i described earlier the voltage slowly rised up until it reaches 18V (Whit battery connected)
 
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