1989 88 spl charging question sanity check

[big boat little motor]

I finally got the boat out today and did a little tubing with it. I noticed that the tach would drop down to 1000 rpm after it climbed to 3000 to 3500 and if I brought it back to that rpm range it would start operating again. I thought it was a little weird at the time but it seemed to be running OK so we stayed out an tubed for another hour or so. When we got done and stopped the motor for a while the battery barely had enough juice left in it to start the motor. From what I have read on the forum it looks like I may have a rectifier heading south on me. Does this sound like a reasonable conclusion as what may be causing the dead battery and weird tach performance?

 

[baiwan]

Re: 1989 88 spl charging question sanity check

If you don't have a charging gauge on boat dashboard check the rectifier by a DVA and replace it.

 

[big boat little motor]

Re: 1989 88 spl charging question sanity check

OK I have an ignorant question What is DVA? I have the service manual and they gave some multimeter tests for the rectifier. Is that what you meant?

 

[emdsapmgr]

Re: 1989 88 spl charging question sanity check

Erratic tachs and discharged batteries are a sign of a bad rectifier. The rectifier provides both functions. Your engine only uses the battery for a few seconds while starting, then the engine runs on it's own power. If you play the radio or use the trim a lot or the lights, it will discharge the battery quicker.

 

[aclmvh]

Re: 1989 88 spl charging question sanity check

BBLM, I had a similar problem with my '98 115SPL, but my tach was fried. There's another thread out here you may have seen about loading up the unregulated charging system such as we have, by turning on lights and things. A voltmeter on the dash is invaluable....I see mine creep up toward 15 ocassionally and immediately turn on some lights!

A DVA or DVom is basically a digital multimeter (digital volt amp meter). Get one for under $6 at Harbor Freight and keep it on the boat.

mvh
Jax/Fl

 

[jonesg]

Re: 1989 88 spl charging question sanity check

DVA is direct voltage adapter, its needed to read ignition and charge voltages on outboards ( some cars too).
Get a DVA meter off ebay. about $60.
I made an adapter to fit my meter, its easy.
http://forums.iboats.com/showthread.php?p=2016261#post2016261

 

[big boat little motor]

Re: 1989 88 spl charging question sanity check

Thanks for all of the help on this. This forum is sure a great resource

 

[big boat little motor]

Re: 1989 88 spl charging question sanity check

I just wanted to thank you all. I bolted up the new rectifier and a funny thing happened....... The tach worked.