Trying to Locate Hydraulic reservoir

[Cartouche]

We have a 2003 Mainship 390, and I am trying to locate the Hydraulic reservoir for the trim tabs, Motor is working fine, but the tabs will not move, I am sure I have a leak and just need to trace the system many thanks

 

[porman]

On our 2003 Mainship the trim tab reservoir is part of the pump. There is a small black plug. Sorry, not at the boat and I can't remember the brand of the tabs. I know it's not Bennett.

 

[Keysdisease]

In 2003 your 390 probably has Bennett. Small chance they are TrimMaster. If you can find the black tubing coming in through the transom the pump in most boats is usually in the vicinity of the steering gear. They do make some noise so maybe open the aft cockpit hatch and have someone activate the control while you listen. As mentioned, the pump and reservoir are combined

The pump uses ATF

What makes you think you have a leak?

Bennett has a very good trouble shooting guide at their website and excellent customer service

https://bennetttrimtabs.com/

 

[porman]

Keysdisease, thank you for jogging my memory. The trim tabs on our Mainship are indeed TrimMaster.

 

[Cartouche]

In 2003 your 390 probably has Bennett. Small chance they are TrimMaster. If you can find the black tubing coming in through the transom the pump in most boats is usually in the vicinity of the steering gear. They do make some noise so maybe open the aft cockpit hatch and have someone activate the control while you listen. As mentioned, the pump and reservoir are combined

The pump uses ATF

What makes you think you have a leak?

Bennett has a very good trouble shooting guide at their website and excellent customer service

https://bennetttrimtabs.com/

I can here tab motor running when I move the levers but the tabs do not retaract and extend, thus my thought is it has lost fluid

 

[Cartouche]

In 2003 your 390 probably has Bennett. Small chance they are TrimMaster. If you can find the black tubing coming in through the transom the pump in most boats is usually in the vicinity of the steering gear. They do make some noise so maybe open the aft cockpit hatch and have someone activate the control while you listen. As mentioned, the pump and reservoir are combined

The pump uses ATF

What makes you think you have a leak?

Bennett has a very good trouble shooting guide at their website and excellent customer service

https://bennetttrimtabs.com/

They are Trim Master

 

[porman]

Trim Master used their own special fluid, about which I haven't found much information. I've been told that ATF is acceptable, but I'm still not sure about that. If anyone here has more accurate info I would appreciate it.

 

[Keysdisease]

I can here tab motor running when I move the levers but the tabs do not retaract and extend, thus my thought is it has lost fluid

Not necessarily. I'm a Bennett guy, but TrimMaster operated in a very similar fashion. The pump has 3 electrical components, the motor and 1 solenoid each for port and starboard actuators. In order to deploy or retract a tab the motor has to turn and the appropriate solenoid(s) need to open, simultaneously. If there is an electrical problem with a solenoid you could hear the motor run but the tabs would not move because the solenoids do not open. From corrosion in wiring, control or connections, the motor will just run slower, but the solenoids are much more voltage sensitive.

There is usually a connector between the wire harness and the pump near the pump that is often the culprit. Connections at the control are sometimes the problem. You may have a leak, in which case you would have fluid in the bilge or a sheen on the water.

Find the pump by ear, if it has fluid you may just need to clean some elect connections. A solenoid or the control may need to be replaced. But if you can hear the motor running, the pump itself is usually good.

The basic Bennett troubleshooting guide is still a good tool across hydraulic trim tab brands for both Boat Leveler and TrimMaster

 

[Cartouche]

Not necessarily. I'm a Bennett guy, but TrimMaster operated in a very similar fashion. The pump has 3 electrical components, the motor and 1 solenoid each for port and starboard actuators. In order to deploy or retract a tab the motor has to turn and the appropriate solenoid(s) need to open, simultaneously. If there is an electrical problem with a solenoid you could hear the motor run but the tabs would not move because the solenoids do not open. From corrosion in wiring, control or connections, the motor will just run slower, but the solenoids are much more voltage sensitive.

There is usually a connector between the wire harness and the pump near the pump that is often the culprit. Connections at the control are sometimes the problem. You may have a leak, in which case you would have fluid in the bilge or a sheen on the water.

Find the pump by ear, if it has fluid you may just need to clean some elect connections. A solenoid or the control may need to be replaced. But if you can hear the motor running, the pump itself is usually good.

The basic Bennett troubleshooting guide is still a good tool across hydraulic trim tab brands for both Boat Leveler and TrimMaster

Many thanks Next time at the boat I will see if there is fluid cheers

 

[Pmcsurf1]

We just bought 2004 Mainship 40 with trim tabs. Why a 8 to 9 knot boat has trim tabs is beyond me. Ours were stuck down at about 25 degrees and wouldnt come up. A buddy loosened the nuts on holding the lines to the pump and like bleeding brakes he would loosen the nuts while I pushed up on the tabs. Caught the oil in a bowl. I'm considering removing the tabs next time we're on the hard. Right now the only purpose my tabs serve are a spot for growing barnacles.

 

[C lectric]

Before you write the tabs off try an experiment.

Back them off fully when you next go out. Once up to your cruise rpm try applying them a bit at a time. At some point of application they may take enough load off to lift the stern which you may be able to hear in the engine note. If good enough they may actually allow a hair more boat speed.

They can also be used to remove a running list and get the boat to level out.

My slow boat, 7 -8K reacts to my tabs. I too thought useless but not so.
As explained above I can hear the engine note change to a lighter note.

The large stern wave is reduced substantially as is a list while running.

They have to be reduced as I burn off fuel as my fuel tanks are under the back deck.

Maybe for your boat they have no value but try my experiment before just removing the tabs. You may find they make more of a difference than you think.