Trim and tilt pump not moving outdrive

Caniwi

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Jul 13, 2020
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4
1995 Mercruiser 4.3; alpha one gen II; oildyne pump (2 solenoids)

Mechanical problem: outdrive not moving when pump motor is running
Electrical problem: controls are not starting pump motor
  • Tilt and trim pump bracket rusted out, so replaced it. Tilt was working last season.
  • Accidentally bumped new bracket with red wire from battery when re-installing and it shorted out (…forgot to shut off power…).
  • Drive is stuck in up position. Tested trim up and down and pump motor sounded normal and turned over but no movement of drive.
  • Verified that the pump was pumping fluid out “up” port.
  • After a number of times running the pump, the pump motor slowed down almost to a halt. The next day, tried again and only got a single solenoid click (both up and down) and motor didn’t turn over.
  • Got hold of a “loaner” (pump B, which has had little use) and installed. The only difference from pump A was that the solenoid sounded like it was rapidly switching open and closed.
  • I connected each pump directly to the battery and verified that both pumps are pumping fluid up and down. So, pumps seem to be fine.
  • Suspect the mechanical issue might be a frozen ram?
  • Electrical issue: not sure where to go from here to find out why the controls are not starting the pump motor? I cleaned all the terminals on the solenoids and tested and cleaned both the 20A and 110A fuses. Have done a number of tests for continuity and haven’t found any issues but of course, not fully knowing what I’m doing means I may have missed a few things!
Any pointers to reliable resources for testing procedures would be much appreciated as well as any direct suggestions. Learning as I go…
 

achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
Rapid switching of the solenoids is a very low battery.

If you stored the drive tilted all the way UP (Owner's handbook specifically advises against this), then it's likely the ram end caps have corroded and 'grabbed' the piston rod. As the DOWN pressure is about half the UP pressure, and acting on about half the piston area, you get about 1/4 of the force driving DOWN as UP. Try having someone stand and bounce up and down on the drive while you hit DOWN (once you've charged the battery)...

Chris.........
 

Caniwi

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Jul 13, 2020
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Great, thanks achris. The guy I borrowed the pump from said the same thing. I'll try it out tomorrow.
 

Caniwi

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I just checked the battery which reads 13.7V and the power at the pump is only 9.4V. Any ideas what might be causing that?
 

achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
Dirty connection... Remove and clean all connections, and don't forget the negatives too. ;)

Chris...
 

Caniwi

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Jul 13, 2020
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Thanks Chris. With a squirt of WD 40, a few taps on the rams and some human weight, I got the drive to move! Had to jump the down terminal to the battery to get it going but it works.

I cleaned both ends of all the battery connections and still have a loss of voltage. I guess 9.4V is not enough to turn the pump over? I'm thinking now that I need to test the cables between the pump and main power switch, and power switch to battery. Will see how that turns out in tomorrow's adventure into the unknown.
 

Bondo

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Apr 17, 2002
Messages
71,307
I cleaned both ends of all the battery connections and still have a loss of voltage. I guess 9.4V is not enough to turn the pump over? I'm thinking now that I need to test the cables between the pump and main power switch, and power switch to battery.

Ayuh,..... Welcome Aboard,....... Don't forget the Grounds too,.......
 
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