VP DPS-A External Tilt/Trim Pump Blows Fuse With Boat in Water, Works Fine on Trailer

MikeOfWarr

Recruit
Joined
Jul 30, 2015
Messages
3
[FONT=&quot]Short story:

The 10 amp fuse for the VP external tilt/trim pump blows when boat is in water. Replace fuse when boat on trailer for couple days (time for outdrive to dry out) the tilt/trim works fine.

Details:

I have a 2007 Chaparral Sunesta 234 with a Volvo Penta 5.7 with the DPS-A outdrive. This outdrive has the External tilt/trim pump mounted next to the outdrive. After a day on the lake I tilted the outdrive up to load on the trailer and pulled up to my covered storage area at the marina. After stowing everything away I tried to lower the outdrive as I always do when the boat is stored. Nothing happened.
[/FONT]

[FONT=&quot]The 10 amp fuse located in the fuse block on top of the engine had blown. Inserted a spare fuse and it immediately blew when I tried to lower the outdrive. So I towed the boat home and began troubleshooting. I removed both relays and the blown fuse. Turned battery power off and removed the trim switch from the control handle. Tested with a multi-meter and appeared to be working fine in both switch positions. No sign of burned or bare wires. [/FONT]
[FONT=&quot]Not knowing what I was doing, I loosened the two allen type screws next to the outdrive on the pump cover where the 4 hydraulic lines go in (I was looking for possible electrical connections in that area). When I began to loosen the screws hydraulic fluid started leaking out and the drive slowly came down. I quickly tightened the screws and the fluid stopped. Not much fluid leaked out, just a small puddle in the driveway. Probably only 2 or 3 ounces. [/FONT]
[FONT=&quot]So I topped the fluid up, replaced the relays and inserted a new 10 amp fuse all the connections were clean and no corrosion present. Turned on battery switch, tried the trim switch and magically the trim motor started working. I have a second trim switch back at the transom and it functions also. After cycling the outdrive up and down once I topped off the fluid again. Cycled the outdrive a few more times and added more fluid. Did this process 5 times until I could no longer top off the fluid. When all was said and done I had added a little over a half a quart of fluid and did not blow any more fuses.[/FONT]
[FONT=&quot]Not sure how I fixed the problem but was wondering if low trim pump fluid would cause the pump motor to blow a fuse. [/FONT]
[FONT=&quot]So I take the boat back to the lake, launch it into the water and the fuse blows again.

I talked to a mechanic at the nearby marina and he indicated Volvo Penta had problems with their external tilt/trim pump leaking fluid but not aware of a electrical problem unless the motor was bad. He said the tilt trim sensor was on a separate circuit and not the fault of the fuse blowing (helm gauge still showed the correct position of the outdrive). I cannot see any exposed wires around the external pump so I am confused why the fuse would blow in the water but not on the trailer (after returning home and time to dry out).

So back at home the second time, I replaced the fuse and the tilt trim pump is working again. I tried both switches, the one on the control handle and the aft remote tlit/trim switch. Both worked fine as the outdrive goes up and down without issue. I sprayed water around the tilt/trim sensor and the external pump but could not replicate the fuse blowing.

Any ideas as to what the problem could be?
[/FONT]
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,583
Not much there, its either a relay or the pump. Relays can draw more current just like the trim motor if windings start shorting together internally. Pull the relays and measure the resistance of the coil, pins 85 and 86

relay contacts.jpg
 

MikeOfWarr

Recruit
Joined
Jul 30, 2015
Messages
3
Thanks AllDodge, I'll try that test.

So you don't think there is water incursion somewhere. I'm thinking maybe water could be getting behind the external pump and shorting out somewhere. I'm thinking about removing the six bolts holding the pump on and inspecting the gasket and wiring. Not sure if I can do this without removing the hydraulic lines.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,583
Don't know if corrosion is the issue, just figure start with the easy stuff.
 

MikeOfWarr

Recruit
Joined
Jul 30, 2015
Messages
3
Tested with a multimeter and resistance is the same between 85 and 86 on both relays. I ordered a Seloc repair manual and waiting for it to be delivered to see if I want to venture in to remove the external pump.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,583
Seloc is a potty word around here. I would suggest taking it to the local starter and alternator repair shop and let them do it.
 
Top