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1997 Johnson 200 Ocean Pro Erratic Tach and Voltage meter

T

tigerjim

New member
I have had an erratic tach reading for several years and lately a volt meter that would only read a little over 12VDC with the motor running. It would increase only slightly when I would rev the motor. Browzing these threads on charging problems I came upon "Testing Tachometer with Water Cooled Regulator/Rectifier" by J. Reeves. I unbolted the power pack to look at the rectifier and could see the yellow wires, purple, red and gray wires mentioned in his article. What I did not find was the terminal strip he mentioned in the article so i could swap gray wire to yellow/gray stripe to check tachometer. I did make some voltage checks at battery terminals : motor off = 12.6 VDC; motor @ idle 13.2 VDC; and Motor @ 3500 RPMs = 14.8VDC. After taking these voltage checks I noticed the volt meter was reading close to what I was seeing at the battery terminals, before only a little over 12vdc. Does it seem like my charging system is working properly? I still would like to fix the erratic tach, sometimes it will peg out over 7000 rpms, then may read fairly accurately for a while then read higher than I am running. I just cannot depend on it, right now at idle it was reading 2000 rpms. Where is this engine electrical terminal strip Mr. Reeves has mentioned in his article?
Thanks,
Tigerjim
 
you may find that the voltmeter is either reading to high or just the battery output with no charge on it....i am not familiar and have no diagram for that motor but the tach works off the same pulse thats feeding your battery...(that voltage is not a flat line dc and has pulses)...what joe is doing is taking the grey wire that feeds the tach and putting it directly on the stator output...if the tach works like that you got a bad rectifeir/regulator depending on which you have..if it dont work or if the intermittent is still there you either got a bad tach or intermittent open in the stator....almost no chance of you having a bad tach and a bad voltmeter at the same time so trust your meter...
 
tigerjim said:
I don't recall the voltmeter having issues before, even when the tach pegged, I will make certain I look at the voltmeter when the tach pegs.
Click to expand...

I started motor today, tach went all the way to 7000 @ idle, voltmeter a little over 13 volts, shortly after that tach went to normal (1000 rpm @ idle) and every so often it would jump around. I could not see a correlation between voltmeter and tach during these rpm erratic readings. Is there a terminal strip on this motor where I can feed the gray tach wire to the yellow wire from the rectifier to check out tach operation>
 
i dont have any info on that motor...maybe someone can jump in and help you....but there should be a term strip near the regulator with the grey wire from the tach..on that same strip there should be two wires from the stator...probably yellow...they are feeding the regulator.... just move the grey wire to one of these...what you are doing is feeding the tach directly from the stator....when you say you unbolted the power pack i hope you are talking about the regulator and not the ignition pack....
 
papyson said:
i dont have any info on that motor...maybe someone can jump in and help you....but there should be a term strip near the regulator with the grey wire from the tach..on that same strip there should be two wires from the stator...probably yellow...they are feeding the regulator.... just move the grey wire to one of these...what you are doing is feeding the tach directly from the stator....when you say you unbolted the power pack i hope you are talking about the regulator and not the ignition pack....
Click to expand...
The exploded parts diagram of the Johnson 200 Ocean Pro on this site called the part I unbolted the power pack. It is located above the regulator/rectifier. I saw the grey wire and the two yellow wires but did not see a terminal strip. Maybe I will have to splice the gray wire to the yellow wire to test the tach. Thoughts? Thanks for responding.
 
if you look at the regulator and look at the wires coming and going from it are they all feeding into plugs and not to a terminal strip?where is the grey wire connecting to the regulator?through a plug?in rereading your first entry first and 2nd sentences it appeared that you had a regulator problem..then later your readings appeared accurate for a working regulator....if all the statements are correct then you have a regulator output that is intermittent...that can be the regulator or the stator windings...possibly a bad connection in either the feed to the regulator or output...this is a simple circuit....you have a winding with 2 wires that feed your regulator from the stator....the output goes to your battery charging circuit and then the grey wire is added to the output to feed the tach..the input from the stator is ac...the output from your regulator is not completely filtered and has pulses riding on top of a dc output...these pulses have a frequency that is relative to the ac sine wave from your stator which are used to measure rpm...thats all there is to it.......if there is no terminal strip you could cut the grey wire and just skin the insulation off one of the yellow wires and connect the grey wire there ..you may have to solder to get a reliable connection...when you cut the grey wire make sure you dont cut right at the plug..you are going to have to restore the wiring back to original eventually..if the tach works then you have in all probability a bad regulator...if it still fails then its probably the tach....i would watch that voltage output closely though either way...its also possible that you have a intermittent winding problem in the stator...you say you have had a long time problem with the tach...its also possible that you have developed a 2nd problem in this area....just watch that voltmeter like a hawk...
 
i am 30 minutes from you in Baton Rouge but i aint physically working on your motor...i just got back from three days working at my camp in this heat and no fishing and am seriously thinking about selling all my toys and fishing with a guide or off a frigging pier or something..
 
My engine has plugs instead of a terminal strip, today I started engine to get a baseline before I started cutting and strpping wires. The tach immediately went to 7000 rpms then came down in short while to idle @ 1000rpms, then it would spike and be erratic for a while, I then shut motor down and located the gray wire, cut & stripped the end and soldered it to the yellow/gray wire from stator going to regulator. I started motor, tach had same symptoms as earlier, removed and attached grey wire to yellow wire with same results. Voltmeter was stable during the tach swings. Thoughts?
 
sounds like the tach then...the only thing left to do is if you can get a meter on the tach wiring and check if you have a consistent feed while the tach is jumping around..in the rear of the tach you may have different positions for different motors....you may change these around and then go back to the original and see if you had a flaky connection but it sounds like a tach...i put a new motor on last year and the setting need changing (evinrude 90 to merc 60) and it had been in the weather too long and had to change to a new tach...cost was a little in excess of 100 bucks but that was dealer installed..dont know his markup...
 
Your engine has no terminal strip. Joe wrote the piece a while ago, before they went to plugs, etc.
Your voltage readings are indicating that the regulator/charging system is working.
If the charging system is working, then the yellow pair wires from the stator are good too.

You should have your grey wire connecting under the pack with a bullet connector. The yellows go to a big round black two conductor connector.
This connection system doesnt not allow for temporarity splicing in the grey to the yellow/grey.
 
I unsoldered the tach wiring fron the yellow/gray wire and reconnected to the gray wire, taped all bare spots on the wiring. I then started motor, tach was still erratic so I shut down motor and pulled gauge panel to check wiring on gauges, Tightened connections on tach and started motor, the arrow on back of the tach was between 5 and 6, supposed to be 6 and tach was flaky, moved to a little past 6, tach stable but reading low at idle. I then moved the arrow next to 5, tach stable but was reading 1300 rpms at idle when it would normally be about 1000 rpm. The tach was stable and voltmeter ranged from 13.6 volts at idle to 14.8 VDC at 3000 rpms. It appears you were right about a flaky connection at position 6. Thanks for your time and help.
 
So my tach does not work at all, had an issue with rectifier shorting out and replaced, so purple and gray supply the tach, if this is correct I will pop cover off and check connections, does that sound right?
 
tigerjim said:
I have had an erratic tach reading for several years and lately a volt meter that would only read a little over 12VDC with the motor running. It would increase only slightly when I would rev the motor. Browzing these threads on charging problems I came upon "Testing Tachometer with Water Cooled Regulator/Rectifier" by J. Reeves. I unbolted the power pack to look at the rectifier and could see the yellow wires, purple, red and gray wires mentioned in his article. What I did not find was the terminal strip he mentioned in the article so i could swap gray wire to yellow/gray stripe to check tachometer. I did make some voltage checks at battery terminals : motor off = 12.6 VDC; motor @ idle 13.2 VDC; and Motor @ 3500 RPMs = 14.8VDC. After taking these voltage checks I noticed the volt meter was reading close to what I was seeing at the battery terminals, before only a little over 12vdc. Does it seem like my charging system is working properly? I still would like to fix the erratic tach, sometimes it will peg out over 7000 rpms, then may read fairly accurately for a while then read higher than I am running. I just cannot depend on it, right now at idle it was reading 2000 rpms. Where is this engine electrical terminal strip Mr. Reeves has mentioned in his article? Thanks, Tigerjim
Click to expand...

You must have skipped over a few lines James. Scroll down to the RED type.
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(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).

A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging system, and the tachometer simply doesn't register.

However.... those water cooled regulator/rectifiers that are used on the 35 ampere charging systems (and some others) bring into play a different type problem, and as you've probably found out, they are really a pain to troubleshoot via the proper procedure. There's an easier way.

The tachometer sending/receiving setup operates off of the gray wire at the tachometer. That same gray wire exists at the engine wiring harness which is connected to the engine electrical terminal strip. You'll see that there is a gray wire leading from the regulator/rectifier to that terminal strip, and that there is another gray wire attached to it. That other gray wire is the wire leading to the tachometer which is the one you're looking for.

NOTE: For the later models that DO NOT incorporate a wiring terminal strip, splicing into the "Yellow Wire" mentioned will be necessary.

Normally the Gray wire leading from the tachometer is attached at the terminal strip to another Gray wire which leads from the water cooled voltage regulator/rectifier...... remove the gray wire that leads to the tachometer. Now, find the two (2) yellow wires leading from the stator to that terminal strip. Hopefully one of them is either yellow/gray or is connected to a yellow/gray wire at the terminal strip. If so, connect the gray wire you removed previously to that yellow/gray terminal. Start the engine and check the tachometers operation, and if the tachometer operates as it should, then the regulator/rectifier is faulty and will require replacing. If the tachometer is still faulty, replace the tachometer.

If neither of the yellow wires from the stator is yellow/gray, and neither is attached to a yellow/gray wire, then attach that gray tachometer wire to either yellow stator wire, then the other yellow wire, checking the tachometer operation on both connections.

I've found this method to be a quick and efficient way of finding out which component is faulty.... the tachometer or the regulator/rectifier. It sounds drawn out but really only takes a very short time to run through. If the water cooled regulator/rectifier proves to be faulty, don't put off replacing it as they have been known to catch on fire with disastrous consequences.
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Ok, will try the above, I do not believe I have the terminal strip so will try and hook the gray wire and splice into the yellow gray. Thanks.

My previous rectifier did short out - melted pretty good but disconnected the battery cables before actual fire started, in that case would that have killed the tachometer?

The one I replaced is not new, a used one, the one that actually shorted out was brand new.
 
Now the question I forgot to ask, if the tach works hooked to the yellow gray wire do I leave it hooked up or get a new rectifier, mine is the water cooled.
 
I just noticed that "tigerjim" has become "Chuck Guider ??

Jim changed his name or a "accidental" hijack? I'm thinking a new post/thread should be started?
 
Chuck Guider said:
I did not change my name, voltage good charging, gray wre to yellow gray no tach, guess time to replace
Click to expand...

You're posting under someone else's thread/post Chuck. That's looked upon as "high-jacking"... also in this case it's confusing as hell mixing in with the similar problem of Jim's. Best to start your own thread so everybody can join in. Top left of previous page, blue rectangular box states "Start New Post" or something similar... click on it.
 
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