Help Hydraulics - Houston 90 HP Yamaha Outboard

[smcconinc]

Howdy.
Well, the trim / tilt has been interrmitent. Took it all apart, motor and switch are fine, lots of metal in motor area - cleaned it out. Motor runs fine when disconnected - in both directions.

Plenty of hydraulic fluid, motor runs tilt and trim work fine. Then stops. Then goes. Then stops. Goes up/down a little stops. Then goes. Sometimes runs all the way up / down - but generally goes about 10-40% then stops.

Checked hydraulic fluid - plenty.

We have 12 volts to the switch - no loss in power at the switch when hydraulic pump stops.

Ideas?

How do I check the pump motor to see if that is the problem.

HELP.

[Schematic]

have you checked for power loss RIGHT AT the motor?


That will tell the tail. How did the brushes look?

[smcconinc]

No I haven't - and can you please tell me how do I check for power loss right at the motor? There are the 2 wires into the motor - can I get a reading on them without taking the motor back off (which is a major pain).

The inside of the unit was a little dirty, but not too bad. I cleaned everything with a light grit sandpaper (the brushes and the coil) and put it back together. I did notice that one of the little brush connector wires was more worn than the other - but it still looked OK.

When I re- assembled and hooked up to the switch (before installing back on the hydraulics), it appeared to work fine. Then when I put it on the hydraulics and tightened everything down - it was intermittant again. I also noted that it ran in the reverse direction - even though I had it wired up correctly at the switch (maybe I moved something inside during the re-assembly - but not an issue, I can just switch the leads).

Please get back with me on this - I am hoping this is a simple test / solution.

Thanks. Steve

[smcconinc]

Also - yesterday I said there was lots of metal in motor. This isn't very accurate. In the motor itself, there was a small amount of metal shavings.

There was a decent amount of little metal and rust type particles in the hydraulic mount area - where the motor mounts to the hydraulic pump area. Inside the pump housing, there was more junk than I expected - so I used paper towels and then a screw driver to get this stuff out.

Also - I am thinking that the lead wires from the switch could have a problem - should I cut the housing off them and inspect for pinches / cracks?

Thanks.
Steve

[99yam40]

hook up a volt meter to the motor leads where they attach to the T&T relays,
When you hit the up and down switch you should see 12 volt + and 12 Volt - depending on which switch is pushed.
If you are seeing the voltage at the relays then the motor should turn .
Unless like you said the wires are bad or something inside the motor.

Remember both the + and - have to be swapped to change the direction of motor, so if one relay does not make up the motor will not run.

If you cut open wiring then you will have to seal it some how, but motor replacement would be best

[smcconinc]

Thanks. We tested with a light bulb 12v dc tester and not a volt meter last time.
My electrical skill are not good - do I hook up both leads to the t&t switch leads at once, or do I need a ground. If I recall properly - I should hook up to both t&t leads at once, but want to confirm.

Thanks.

[smcconinc]

Just tested it with volt meter. It hold 12V all the time at the switch connection, even when the little motor stops running. I am assuming it is an internal failure of the motor and and going to replace accordingly.

Thanks for the help.

Steve

[rodbolt17]

ok
one more time.
the trim switchs,both handle and pan, simply control a relay that controls the trim motor.
this allows a very small operating CURRENT to control a large current draw device.
at the relay terminals one is blue the other green and are 10 ga wires.
the trim switch is protected by the 20 amp ign fuse.
the trim motor has an internal bi-metal contact that will open if the current draw of the motor exceeds desighn spec.

on to the relay.
at rest BOTH contacts are grounded,means both output posts that the motor wires are connected to are at ground potential.
when the UP button is depressed current flows through the relay windings associated with the blue wire.
this causes on set(blue) of contacts to close.
this contactor now makes the circuit between the red post on the relay and the blue post.
current now flows from the blue post through the motor windings and returns to ground via the green post.
the same is true when when the switch is depressed down only its the GREEN post that now becomes positive.

test lamps are so worthless that I havent owned on in over 15 years.

place one digital meter lead on the threaded green post,the other on the blue post.
hit trim up.
shuld read abobve 11V either + or -.
hit down.
should read the same with the opposite polarity of the first reading.

if your using an analog meter then the procedure is different.

[smcconinc]

Thanks - I did as you said, got 12 volts at the switch / wire connection in one direction and -12 v in the other. The motor still only worked part of the way up (or down) and then would stall - no loss in voltage.

Unless I am wrong, this means there is an internal problem with the motor. I have ordered a replacement motor.

Thanks again.
Steve

[rodbolt17]

if your testing was done at the relay and not the switch I suspect the thermal overload device is opening in the motor assy.