1989 DT200 - I'm running out of options?!

[Solarman]

Dt200, running issues

Hey Chris, sorry for the problems.
yes, seems like tach reading did change. It may be the rectifier that caused the change, or the wiring you worked with in the change.
Check the wiring of that tach control unit, and make sure they are clean & tight. it might also be good idea to check continuity on all the grounds. Anchor one lead to the block well, then test different ground plug connectors around for continuity. Then you can test same color wires for same continuity. On one of my motors I found a bad plug connector with no continuity in a 2” section of wire. It is possible that one or maybe more connectors may have failed.
But, let's focus on the tach reading. I think if we solve that, it could lead us to the cause of your other problems, they seem to be tied together. You should have your wiring diagram handy for all this.
Am hopeful this is some simple fix.

[chackett]

Hey Chris, sorry for the problems.
yes, seems like tach reading did change. It may be the rectifier that caused the change, or the wiring you worked with in the change.
Check the wiring of that tach control unit, and make sure they are clean & tight. it might also be good idea to check continuity on all the grounds. Anchor one lead to the block well, then test different ground plug connectors around for continuity. Then you can test same color wires for same continuity. On one of my motors I found a bad plug connector with no continuity in a 2” section of wire. It is possible that one or maybe more connectors may have failed.
But, let's focus on the tach reading. I think if we solve that, it could lead us to the cause of your other problems, they seem to be tied together. You should have your wiring diagram handy for all this.
Am hopeful this is some simple fix.

Thanks again for all the continued help in tracking this down, I really appreciate it. Working with electrical systems is new to me, so I'm not 100% certain I am following your suggestion above.

I understand continuity, and I understand securing one side of my tester securely to the engine block somewhere, but not sure I'm understanding where to touch the other probe for testing continuity.

I'm also not following on where / how to test the same color wires. Are you suggesting to just find probe points along a same colored wire where the plug connector is between the probes just to test continuity across the plug?

Sorry to be so thick .. enjoying learning a lot though..

Thanks,
Chris

[Solarman]

testing wires 101

Ok Chris, second time writing this.
Basically on a boat all wiring is pretty simple. It's either negative (-) or positive (+), and then you add all the different items (sensors, switches, lights, coils, ECM, CDI, etc. the black wire is the negative and ground. The red is generally the positive. Most of the problems with wires comes from dirty/ loose connections. If you take your ohm meter and connect one side to ground and touch a black wire, you should have continuity.all the negative connections and grounds, even at the battery should have good continuity.
If you're checking a colored wire, you can only check continuity for that specific color wire. If you're trying to check one of the items (listed above), you should check by the method in the manual.
If you run into a wire with poor/ no continuity, then check your wiring diagram to see if there is an item that might interfere.
I hope this well help you understand a little more.
The first time I wrote this it was more involved, and about 3 paragraphs longer. But now I'm tired, and want something to get to you.
Keep us in the loop. Good luck.

[chackett]

Good Morning!

First, thanks again Solarman for sticking with me through this. I'm definitely in this for the long haul, so if you're tired or don't feel like writing a book, don't do it I do sincerely appreciate your help though, so even if we're not sprinting to the finish line, I hope you'll run the marathon with me

I understand much more clearly what you're describing. I think this weekend, I might go get the boat and bring it back to the house so I can work on it more easily. It's tough working on it in the storage yard where there's no power, no water, no bathroom, etc. Plus I'll have all my tools at home.

I found an electrical supplemental manual for my motor on Ebay, so I'l order that today, and then I guess I'll start testing the heck out of the motor.

I do understand too about corroded wires and poor connections. Last year I was getting the various pumps on the boat back into shape, and one of the Jabsco raw water washdown pumps refused to work properly. I used my voltmeter to track it down to poor voltage at the brushes. Turned out that the interior of the braided copper wire were so corroded and rusted that they weren't carrying any voltage to the brushes. I stripped some of the wire and the interior strands basically just crumbled and fell apart. Replaced the wire and pump works great now. Certainly is possible I have some of that going on somewhere else. Although I would have to say the wiring and connections under the cowling are very clean and do not appear corroded or otherwise degraded.

I will keep you posted!

Chris

[Solarman]

dt200, tach & running issues

Hey Chris, that's not a problem. I want you to win this battle.
As I mentioned, we need the tach functional. The rev limit is usually set 2500, to 3k. I think the 3k is the set point for non-harmful conditions, other more harmful conditions (temp, and oil) may be lower. But, your motor is older, and what diagnostics and limits may be different. My concerns are if your tach is malfunctioning, it may be causing some of the problems? We need it to be accurate first, to know it's not interfering with the running.
So, see if your manual has test procedures for that tach control unit. And, yes, I do want you to check the wires from the rectifier, to tach control unit. We do need to know (maybe putting old rectifier back in, might show if new one caused the change?) The change in the tach reading. And while there press the oil reset, just to see if it clicks? Never hurts to try?
And get back to us.

[chackett]

Hey Solarman,

Yeah, I hate to admit it, but I figured I would need to put the old rectifier back in and see if the new one changed the behavior or not. I suppose while I'm doing that I will do all my testing of connectors and ground/earth connections and inspect all the wiring.

I also purchased the electrical systems supplemental manual for my motor so if my regular shop manual doesn't have any test procedure, maybe the supplemental will.

I'll keep you posted!

Chris

Oh .. the oil reset button. Is it supposed to click? I have pressed it before (I believe the motor has to be running when you press it?) .. but I don't recall any click. I just pushed it, but I don't think there was any noticeable "click" .. I'll double check it.

[Solarman]

dt 200, running issues

As far as the oil reset, I'm not sure About a click. I do know if tripped, and affecting the way your motor runs, I'd feel real bad if we didn't at least try to push it. Ha ha.
Yes, do let us know how it's going when able.

[WEDOCQ]

Ah, its a 2-stroke....

No valves!

LOL, you got me there! A leak down test can still be done on 2 strokes, but I believe you have to seal up a few spots to make it work.

[chackett]

Ok not a big update, but did continue working on this.

Earlier I replaced the rectifier / voltage regulator with one I bought off ebay. After I did that the tachometer was reading about 4 to 6 times the actual engine RPM. I put the old rectifier back in and it seems to be down to about 3x actual engine RPM. Not really sure what to make of that.

At one point I thought I fried one of the trim relays. I was able to tilt up, but not down. When I pushed to trim down button I heard a spark from the cowling. Fortunately I found where I missed a ground connection and everything was fine.

A dual battery switch had been installed by the previous owner, and I had always been a little skeptical of it. I went ahead and removed it and tested all the wiring from the battery to the motor and from the motor to the gauges and from the battery to the console wiring block. Everything tested good.

I started disconnecting the giant mess of wires in the console. There must be 50 different connectors up under there. I'll go through and clean or replace all the connectors.

While I was working on the gauges, I did find the small screw you mentioned that is for adjusting the tachometer readout. It started raining on me, so I didn't have a chance to mess with it, but maybe tomorrow after the rain is gone, I'll give it a go.

One question about that though .. the motor sounds very good and normal at idle, and all the way up until the rev-limiter kicks on. The tachometer doesn't actually send any type of signal back to the motor right? If the rev-limiter kicks on, it's because something (the tachometer control unit I would guess) believes the RPM is too high, and I would guess it would do that even if the tachometer were disconnected?

Well, once the rain clears up, I'll finish cleaning up and testing all the wiring at the console and report back!

If anyone has a tachometer control unit, that's about the only component I haven't replaced yet. And BillCon from page one said that he had a similar problem and replacing the TCU solved it for him. I'd be interested to hear more about that if he's still around.

Thanks everyone .. especially Solarman.

Chris

[Solarman]

dt200, running issues

Hey Chris, was waiting to see what was up. If you look up the part number on the tcu, and google a search for that number, it may surprise you on the number out there, just make sure it's the same part #, and it came of a working motor.
And I didn't mean for you to replace all connectors? I just suggested you test them, to see if any were bad.
I don't think it's the tach switch if the rectifier changed the reading, but wouldn't hurt to switch it a few times then put it back.just to try it before you buy another tcu.
Good luck, and let us know.

[chackett]

Hey Solarman,

I know you didn't mean for me to replace all the connectors And I'm not going to replace all of them .. I'm just going to inspect and clean them. Then if there are any that look suspicious, I'll replace them.

I'll keep you posted! Thanks.
Chris

[Solarman]

dt200

As I mentioned, the tach is tied to the system monitor/ tcu/ computer, and if it's not accurate, it might be sending an over rev situation that may throw your motor into the limp mode. If it is a connection issue, I think it would be at the tcu, or rectifier area, because it changed the reading when rectifier changed. So, to me this says the issue seems to be that area.
Good luck, respond when/ if you find anything, but keep us posted when able.

[BillCon]

Hey guys been busy and havent had much time to get back in here, I, chased around funky tach readings for weeks everything from wires to the unit itself, as soon as it got warmed up it worked fine cold it would read to slow or way to fast, finally I, just took a chance and swapped out the TCU got one off ebay, and it is now reading accurate, I, dont know if thats what is happening to yours but if you go thru all the checks, its the only thing left, I, really think it was also causing the intermitting miss firing and sputtering too. but like Solarman suggest go thru the the wires very closely first

[chackett]

It's been so nice having the boat in the driveway to work on .. and I may have gotten this worked out.

Thanks BillCon for the follow up, I appreciate it. It's interesting that you say yours worked properly once it was warmed up .. I'm not sure I ever ran mine long enough to get warmed up to see if it made a difference. Although mine has always been reading high, never low. And mine always seemed to be to read at a multiple (2x actual or 3x or 4x) .. so where my normal idle is about 700 RPM, tach would read about 1400, 2800, etc ..

I disassembled everything in the console, including all the gauges and every connector. I cleaned or sanded all the connections, labeled everything and then re-assembled everything. Took two days to go through it all. I also turned the adjustment screw back and forth (coming back to original position) as Solarman suggested.

Even though I didn't intentionally change or replace or fix anything, when I cranked it up, the tach seems to be reading correctly. I haven't lake tested it yet, but on the muffs, it does appear to be reading correctly.

There is definitely still some electrical weirdness going on as the audible alarm will sound briefly whenever any electrical accessory is used. So if I press the trim/tilt buttons on the throttle the alarm will sound. Same thing if I start the bilge pump .. even if I turn on the fishfinder, the audible alarm will sound. Not sure what to make of that.

My port side water temp light on the multi-indicator will come on after about 30 seconds of running on the muffs, along with the audible alarm. I'm not going to make too much of that until I actually get it in the lake and test it properly.

I hope I can bug out of the office early one afternoon this week to get the boat in the water and give it a proper test.

Thanks everyone, and I'll let you know how the test goes.

[BillCon]

Thats sounds like a backfeed, somewhere between the motor and the dash gauges, if the remote has ever been taken apart check it again for a pinched wire when it was reassembled,something is triggering the spike, you may have to do the painfully slow process of going thru each wire one by one with continuity testing to find the culprit.