DT40 trim motor...i think?

[seanfishy]

Just getting a second opinion on this mainly.

1987 DT40C

tilt motor just was rebuilt and reassembled, I put it back on, wired everything (initially had up/down backwards, fixed that) Went to use it and smoked a bonding wire pretty good.

It functions well, but for some reason smokes my bonding wires. I believe this would indicate a bad ground, however it has been fine without the tilt on for well over 2 years. After just having it rebuilt, figured its fine to leave connected temporarily.

Wired ground to the starter ground and went for quick run ~20min, back to dock and starter motor is fried, I'm not sure if that was the cause or just happened to odd timing. New starter now, disconnected tilt motor and wired direct to battery. I get arcing regardless of up or down. I pulled wiring shrink entirely off thinking maybe old/bad, nicked etc wires, but nothing. I expect some spark due the amp draw from the tilt motor, but not an entire arcing and almost welding to battery. Motor does not get hot but will run and function with direct wiring.

Also if touch ground wire from tilt motor to neg battery terminal I get a spark while engine is wired to battery (and off). I believe this shouldnt happen due to the motor housing being grounded through the motor itself already. There should be no voltage or any electrical change from this if I understand electricity correctly.

Unless anyone thinks otherwise, I believe I have isolated this down a short or bad ground in the trim motor which oddly enough I need mainly for one simple single reason....getting the boat into my driveway. A 2x4 works, but its a whole lot easier with a power unit.

I have had a mechanic tell me could be a possible weak ground in the motor (he never physically looked at the motor), however my issue with this is that there were never any shorts or odd behavior prior to the power unit reinstall. Sorry for being so long winded but I realize you guys have my words to go off of and nothing further.

[Solarman]

dt40, tilt problems

Sounds like you've got wiring mixed up somewhere. It sounds like you are sending voltage to ground. Check continuity on each wire to ground, if more than one wire has full continuity to ground there is a short inside unit. If only one wire, then your wires are probably connected wrong? If just rebuilt, is it possible wire colors got mixed up?
Good luck, let is know.

[seanfishy]

Ok continuity results from motor only. This is the original 3 wire motor at 27yrs old. Black, red, blue wires.

Ground (black) to blue (+12v up) is 0.01

Black to red (+12v down) is 0.00

Red +12v down to +12v up is also 0.01. This may be ok, but but something isnt logical to me here as everything had continuity with each other leaving no open circuit.

I can test solenoids if necessary, but if I am going there I want to rule out motor first.

Edit >> currently im afraid to reconnect the power unit to engine so these measurements are taken entirely disconnected.

[redlowrey]

I assume it has two relays for the trim motor, and did you pull the trim motor apart. If you did where was the black attached.

[Solarman]

dt40, trim motor

Ok, also check continuity to casing with each wire. If this checks ok, then should be able to put 12v to either blue, or red with black to negative without problem. Just to test the motor.
What was original problem before motor was rebuilt?

[seanfishy]

Yes there is are 2 relays. Ground was connected to starter post ground which goes directly into the engine block. When connected, continuity from (-) terminal to ground was 0.00 ohms on any scale used.

I have tried a few different grounds and get the same result with the bonding wire getting hot (I wont smoke it anymore). If I understand electricity properly, this tells me the bonding wire is becoming the path of least resistance to shorting out for some reason.

The only thing I have not done is physically pull the motor apart. The last thing done when reassembled was the brushes were changed and it reassembled by a reputable shop near here. (It came with the boat in pieces). I do not know if the shop that did the work bench tested however and they have not charged me knowing the issue I am having.

[seanfishy]

Solarman >> I am unaware of the original problem with it or the reason it was removed. It came with the boat when I bought it, and I briefly asked, but wasnt given a straight answer on it. As everything else was fully functional it wasnt too big a deal.

How should continuity to casing check out? That may be one thing I haven't checked.

[Solarman]

dt40, trim motor

All grounds from engine block to negative post of battery should have full continuity. If you touch negative post of battery, and any casing (starter housing, motor block, trim motor casing) should have total continuity. The solid black wires are usually all tied to ground in their circuit somewhere.

If trim motor was put together and bench tested, it probably is fine. But checking doesn't hurt. If a wire got pinched during assy and not bench tested, it could be shorting to ground/ case? Slim chance, but possible.
Just my thoughts going through wiring of your system in my head.

[seanfishy]

All grounds from engine block to negative post of battery should have full continuity > YES - Highest resistance measured was 0.09 ohms from any ground including prop nut.

If you touch negative post of battery, and any casing (starter housing, motor block, trim motor casing) should have total continuity. The solid black wires are usually all tied to ground in their circuit somewhere. >> YES, Neg battery to tilt motor unit housing was 0.02 ohms.

(Also full continuity from housing to either +12V lead)

The tilt unit does function properly, but there is additional current seeking somewhere to go.

If black wire to ground and +12v applied for either up or down directly from the battery, The +12V shorts will attempt to weld to the battery. The result of this short when wired into the engine properly is the short is exiting via the bonding wire.

I think I am going to have a second shop take a look at it this weekend

[seanfishy]

Decided to take motor apart. Bingo...exposed wire on the inside pinched to frame and another looking like it was touching somewhere it shouldn't. At 27 yrs old I think the smarter decision will be to replace the motor rather than repair this one.

[Solarman]

dt40, tilt motor

Then look up the part number for that motor, then google that number, and see what you find. It's also possible to take your motor to an electric motor repair shop, and have them replace the wires put it back together then bench test it.might be less costly.
Good luck, let us know how it goes.

[seanfishy]

I have a friend who owns an alternator/starter repair shop. So thats where I will go as he has already stated he can get an entirely new motor for ~$150 for me. Just replace all the guts and keep the same housing.

This will take a back seat to the new problem however. Ran for ~3hours yesterday and suddenly sputtered and died. I felt an ever slight surging at cruising speed (I need to get a tach for it) just before this happened and slowed to turn around. Got as far as turned around and attempted to get back on plane and down she went. I couldn't restart and ended up having a nice guy tow me to the nearest ramp.

When that happened ball was flat and fuel filter completely empty, so I'm pretty sure it's fuel related.

Back at the house, still couldnt get her going, I'll be working on this as the tilt motor is not entirely necessary for me. Made for an interesting Sunday.

[Solarman]

dt40

Sounds like fuel pick up in tank is blocked, or the vent is blocked up? Did you try opening the fuel cap to see if suction caused problems?
Good luck, let us know how it's going.

[seanfishy]

My thought was fuel issue also. Went through entire fuel line, and found nothing. Only portable tanks, so I dont have much to trace. Changed spark plugs (needed anyway) and seemed to act like kill switch wasnt engaging. Opened control box (kill switch was loose since I got it) hoping to find a loose wire or something out of the ordinary. NOTHING. While in there tightened that up. Tried to fire again. At this point, knowing I have compression, and knowing I have fuel, only thing left is spark.

My thinking at this point is maybe brand new starter isnt turning fast enough? So I went to pull start it and flywheel cover is very loose. Loose bolt from flywheel cover into flywheel. Measure voltage positive to the 2 tight bolts and they measure 12.7V, measure to the loose bolt (backed out about 1/2way) and nothing. Tighten that down and first and 2nd key turn tries to fire. 3rd turn of key no choke fires right up. Why or how that happened, I have no idea, but glad it was an easy quick fix.

[Solarman]

dt40

If you have a fuel/ water separator before primer bulb, check that. It may be water bound? If none of those things mentioned, then check hose & bulb. If soft & weak it may be related to use of ethanol gas, breaking down on inside, if a few years old you might need to replace? If happens again unscrew gas cap and see if air sucks in - vent problem.
Let us know.