Jackplate Questions

[yjewel]

My boat came with non-functioning hydraulic jackplate.
It was pretty easy to figure out that one of the relays wasn't working and the wiring looked like spaghetti.
I replaced the relay and cleaned up the wiring. It works now.

I have a couple of questions reqarding the hydraulic unit.

1) what oil to use?
2) what size fuse?
3) how is the pump attached to the resrvoir? Mine has a little movement and is seeping at this joint.



I'm pretty sure it's a Bob's. I couldn't find anything helpful on their website.

[David - WI]

https://bobsmachine.com/product/jack-plate-oil/

From another site: "SAE 10W is equivalent to ISO 32"

[yjewel]

Thanks. I just found the oil spec on the Bob's site.
I also found a video by Jim Wellman where he goes into great detail on these units. It appears the reservoir is attached by 4 screws and there is an o-ring.
As for the fuse size, Bob's offers a 100 amp circuit breaker. Seems big to me. It implies minimum 8 gauge for the power wires (I think).
I am going to try a few different fuses and see what blows.

[LakeFever]

Whats the deal with using engine oil instead of hydraulic fluid?

[yjewel]

This picture is from the video. You can see the bolt holes.

Mine doesn't have these.

It twists off somehow. i can turn the motor about 90 degrees clockwise relative to reservoir. Then it gets stuck.
It won't turn in the other direction.

Is anyone familiar with this style?

[rgsauger]

Cool. What ya putting it on?

[David - WI]

Whats the deal with using engine oil instead of hydraulic fluid?

All modern (last 40 years) motor oil has the anti-foaming additives... we stopped buying hydraulic oil, power steering fluid, etc back in the 80's.

[Baker343]

I have a Bob's unit, but I've never had to replace the motor and I don't have a fuse. Never had an issue running it like this. I have replaced both relays to the Bob's larger ones after one of the two smaller one's quit. I've always ran ATF with no issues yet. May not be right but it's worked for me.

[wolfgangb]

Hi,
the main circuit breaker on the Mercury (Mercruiser) hydraulic trim power pack, which is installed inboard, and used with the 2.5 ltr ROS (Racing OffShore) motors (one power pack per motor), was originally 90 Amps. It was later upgraded to some 120 Amps, considering the "continuous" use under racing conditions. Do not skimp on the cable sizes for these units, otherwise this is going to end in tears (fire).
Make sure that your motor`s charging system will be up to the task, considering the additional loads of trim and jacking pumps, plus fuel pumps, plus radio, plus instrumentation.
Hope this helps.
Rgds,
Wolfgang (South Africa)

[LakeFever]

Is it marked or easy to identify the 90 from the 120 version?

[yjewel]

This morning I had a Eureka moment.
There was a puddle under the unit. This led me to look at the bottom of the reservoir.
There is a single small bolt that goes through the bottom of the reservoir and attaches it to the pump.
Glad I got it off. The reservoir is disgusting.


Thanks for the info on the Merc circuit breakers. My application is not severe, but I will be careful with the wire size.

1987 V-King with a 200 hp Yami. I bought it last summer. Everything on it needs work. It got to cold to work on the recore, but fortunately there is no shortage of other things I can improve.

[yjewel]

I found the bad news. Cleaning revealed a crack in the reservoir at the mounting hole.
I doubt a replacement is available, but I will call Bob's.
I guess there is no reason not to try and weld the crack with a soldering iron. Any advice?

I also have an old OMC power tilt hydraulic unit. It mounts outside the boat on the clamp or jackplate.
I was hoping to use this all along (to get the unit out of the boat). I am concerned that it may be too small for this application, but once again, nothing to loose.

[David - WI]

I think they are (Parker) Oildyne pumps, not sure which model/configuration... but you should be able to get a new reservoir.

https://ph.parker.com/us/en/compact-...nit-108-series

[wolfgangb]

Is it marked or easy to identify the 90 from the 120 version?

no - only by part ##. Maybe when you buy from third parties (eg Jamestown Distributors or Sierrra), theirs might be marked.
rgds,
Wolfgang