'93 88spl tach works, no charge?

[troska]

I've got a '93 Johnson 88 spl. Tach started to work erratically, so I replaced the rectifier. This is an unregulated rectifier. Tach now works, but doesn't charge the battery.<br /><br />Here is what I've checked:<br /><br />1) Followed Joe Reeves small rectifier check - I've got a reading going one way, none the other for all wire combinations (checking resistance against ground, then against red wire). This indicates rectifier is good.<br /><br />2) DC voltage across battery = 12.5 volts. DC voltage at idle across battery = 12.5 volts. DC voltage at 2500 rpm across battery = 12.5 volts.<br /><br />3) Checking the charge coil (from my Seloc manual) - the 6 amp stator should have 500-610 ohms across leads from stator to powerpack. I'm at 565 ohms. <br /><br />4) Checking continuity from leads (see 3) to ground, should be none. Have none.<br /><br />5) From another post on here "check stator coils for gooey discharge" - found none.<br /><br />6) From another post on here "check stator ohms on 2 yellow leads to rectifier - should be 0.17 +/- 0.5" I'm at 0.17 ohms.<br /><br />7) From another post on here "check stator output with peak reading meter, should be 18-20 VAC across 2 yellow wires to rectifier" I don't have a peak reading meter, I used my multimeter on VAC, and two different multimeters read 35 VAC.<br /><br />So... is it possible that the rectifier is bad, even though the tach works, it is brand new, and it passes Joe Reeves' test? What next?<br /><br />Tim

 

[rickdb1boat]

Re: '93 88spl tach works, no charge?

Tim,<br />I'm not sure what your problem is, as all your tests have passed. But I can tell you that about a month ago I ordered a rectifier for my Evinrude 91' 70HP and it was bad from the get go. Sent it back and got another and no problems now. This is not to say your new one is bad, but just my experience.. The tests that Joe gave passed on my oringinal and first replacement rectifier, also. So I don't what's up...

 

[lark2004]

Re: '93 88spl tach works, no charge?

did u connect the rectifier properly? the leads with ~ go to the alternator and + - go to the relevant battery terminals

 

[rickdb1boat]

Re: '93 88spl tach works, no charge?

Also, check the grounds to the rectifier board. Had this problem, also. Drove me nuts.. The bolt that hold the grounds had come loose bhind the board and I got nothing but intermittant T&T.. They are hidden pretty well back there..

 

[troska]

Re: '93 88spl tach works, no charge?

I'm starting to think the rectifier is bad out of the box, I just didn't know if that was possible with it testing out okay.<br /><br />Lark2004, Yes, connected properly. For this rectifier, there are only 3 leads. Two yellow and one red. In the box with the rectifier, there is a note pertaining to OMC's that says "yellow leads are interchangable". However, I found that they aren't, that the tach works hooked up one way, and not the other. Leads from stator are yellow and yellow/grey.<br /><br />rickdb1boat,<br />I'm not sure what you mean by rectifier board. I've got a rectifier that bolts directly to the block - good ground there. The leads run to an insulator block that serves as a place to connect leads.<br /><br />Any other thoughts? Otherwise, I'm going to see if it is possible to return a rectifier for an exchange.<br /><br />Tim

 

[Toontime]

Re: '93 88spl tach works, no charge?

I have a 94 88spl and have gone through the same scenario. I ended up putting a resistor across the tach connections as recommended on another website and it cured my erratic tach. It makes a difference what kind of battery you use and the state of charge on the battery as to the readings you get. A deep cycle battery will hardly ever show more than 13 volts as it sucks up as much as the rectifier puts out. A standard cranking battery will show 12.5 to 13 volts until it gets tooped off, then the reading will inch up to as much as 17 volts at wot. The charging system will not generate full voltage at 2500 rpm anyway. It may even not keep up with usage if a lot of trolling or low rpm operation is done. I've had a new battery get down to pretty low charge over a period of a month when fishing small waters where I just cranked occasionally to reposition the boat while crappie fishing. An occasional run of 10 minutes at wot will keep her happy. If you want to, you can put a regulated system on it but after the rectifier trick, I'm happy with mine.

 

[troska]

Re: '93 88spl tach works, no charge?

Toontime,<br /><br />The resistor is across the terminals already. The battery is a marine battery, which tries to split the difference between cranking and deep cycle. <br /><br />I agree the system will not develop full voltage at 2500 rpm, but it should (and used to be) around 13.X volts. In my case, I fully charged the battery then ran in the driveway where I had no other load. I too have seen the 17 volts at WOT when the battery is fully charged - with the old rectifier.<br /><br />I'll have a new-new rectifier on Thursday, and report back. I hate it when reading through old posts for info, and there is no follow up.<br /><br />Tim

 

[mrc]

Re: '93 88spl tach works, no charge?

Well the leads should be interchangable... the fact that they aren't is indicitive of a (at least) partially bad rectifier.<br /><br />Good luck,<br />Mike

 

[rickdb1boat]

Re: '93 88spl tach works, no charge?

Tim, there are 2 wires behind the board that ground the rectifier relays. Mine came loose and drove me nuts. finally found them hanging in back of the board where the relays plug in, hooked them back to a ground on the engine block and all was well. I have the same board on the engine.. Don't know if this could be your problem, but thought I would share it with you..

 

[troska]

Re: '93 88spl tach works, no charge?

All,<br /><br />Rectifier was bad out-of-the-box. I was able to return the original for a new one, bolted it up and all was well. Tach works, 13.25 volts at the terminals at 1100 rpm.<br /><br />What was learned:<br /><br />1) Joe Reeves' excellent rectifier test can tell you if a rectifier is BAD, but not conclude that one is good 100% of the time.<br /><br />2) Rectifiers can be bad out of the box.<br /><br />3) If you tach is working, it DOESN'T mean your rectifier is good, or that your charging system is fine. I read several old posts that mentioned this theory.<br /><br />Hope this helps someone else.<br /><br />Tim