Trim Tabs - Dead In The Water

Hello,
Me again, the clueless newbie

Bolstered by the success of changing my prop yesterday, I am not going to try and tackle my non-functioning trim tabs.

I checked fuses, but they are all good and I am not even sure that there is a fuse for it anyways. The "master cylinder"?? was low on fluid so I added about 6 ozs of transmission fluid. I don't know what else to do, or check.

Anyone have any experience or ideas? I do know how to use a voltmeter it that helps any.

Call me CLUELESS

thanks for any help

-Sarah

Re: Trim Tabs - Dead In The Water

Ok,
1: Is this a new to you boat?
2: What kind of tabs are they?
3: When you move the switch, do you hear the pump running? Have to have the engine off and pretty quiet to hear it.

Re: Trim Tabs - Dead In The Water

Hi!
My boat is new to me, and it came w/dead trim tabs.
I 'think' that they start with a 'B' but cannot recall the name,,,Bennett maybe? (embarassed)

They make no noise, no indication of any life in them at all.

I will be going back to the boat later today, I can look at what the manufacturer is.

thanks for replying!

Re: Trim Tabs - Dead In The Water

Ok, I was hoping they were bennett. I have those also, so that helps.
There are probably some wires that are not hooked to the battery that run to the pump/reserver. They are very small gauge wires, one red and one black. The red should have an inline fuse in it. You may have to trace them form the pump to the battery.
Once those are hooked up you should at least hear the pump run and we can go from there.

Re: Trim Tabs - Dead In The Water

Sometimes you can wriggle your test light onto the connections on the wire side of the plug. Get a buddy to hit the switches while you check for power. A google search should net you a schematic. If that checks out try tapping the pump motor while the switches are being pressed. I've seen them stick from sitting. I had one fail on my last boat and when I ordered it they said it's not that uncommon.

Here... found it

Re: Trim Tabs - Dead In The Water

HI Guys

Partial success,,,,,,,,,found & replaced a blown fuse.
Now I hear noise when I work my switches,,,,,but no movement.

Can you unstick them by pushing on them?

Re: Trim Tabs - Dead In The Water

LazyCruiser said:

HI Guys

Partial success,,,,,,,,,found & replaced a blown fuse.
Now I hear noise when I work my switches,,,,,but no movement.

Can you unstick them by pushing on them?

Click to expand...

Thats good.
Yes, I had to lean on mine to get them to move the first time. they had been sitting for a couple years.
They do take a bit of umph to get them to go down and they are spring loaded to come back up so watch your fingers.

Run them up and down a few times then recheck the fluid with them fully retracted. repeat as needed until the level is full when they full up.

Re: Trim Tabs - Dead In The Water

thank you - we will play with them when we can find some shallow water
it's pretty gross here at the marina (I'm NOT jumping in, not here - yuck!)

thanks very kindly, I will beat on them some!

Re: Trim Tabs - Dead In The Water

Sarah,

If you have Bennett Trim Tabs I will be delighted to help you get them going.

Can you tell me how old you think they are?

Here is some basic troubleshooting to get you going.

Let me know what you find:

Fluid: Automatic Transmission Fluid (ATF) any type. Hydraulic Power Unit is self bleeding, running the Trim Tabs up and down 3-4 times will purge air from the system.

Fuse: 12 volt system use 20 amp in-line fuse on positive. (24v & 32v use proportionately smaller)

Red= Port Valve
Green= Starboard Valve
Blue=Motor Forward (pump pressure)
Yellow= Motor Reverse (pump retract)
Black on HPU=Ground
Orange on Helm=Control Positive

Troubleshooting
1.If one side is not operating reverse hydraulic lines on the front of the Hydraulic Power Unit to determine if the malfunction is in HPU or actuator / hydraulic lines. If after reversing the lines symptom shifts to the other side the malfunction may exist in HPU. If the symptom remains on the same side, malfunction may exist with the actuator / hydraulic lines

2. Is the unit receiving a solid 12 volts? Low voltage will some times cause the solenoids to not open preventing the tabs from moving even though the pump motor is running.

3. Conduct the following test:
Remove the wires from the helm control and touch together as follows:
Operation=Reaction
Orange (+), blue, red= Port trim tab down
Orange (+), blue, green=Starboard trim tab down
Orange (+), blue, red, green= Both trim tabs down
Orange (+), yellow, red= Port trim tab up
Orange (+), yellow, green=Starboard trim tab up
Orange (+), yellow, red, green= Both trim tabs up
If the trim tabs function correctly for each wire grouping then the switch is at fault. Also note that any loose or missing screws on the back of the switch (whether a wire is connected there or not) can cause the pump to malfunction.
This test may also be done right at the pump by substituting a "hot lead" for orange. There is usually a connector to the wire harness within a foot or so of the pump. You want to check this connection for corrosion. You may wish to cut the connector off on the pump side and try the test on bare wires.

4. If you suspect corrosion on the wire connector near the pump, cut it out, test as above and reconnect using butt splices.

Re: Trim Tabs - Dead In The Water

Tabman to the rescue!!!

Sarah - do exactly what Tabman tells you. He helped me out a few months ago and everything is working great.

Re: Trim Tabs - Dead In The Water

Wow, TabMan that is excellent!

Here's where I am so far.
- with every toggle of either switch I hear a noise - and the up/down of the switches gives a different noise, giving the impression that they're working.
- however, there is no movement
- so we took the boat to shallow water and I hopped out while Rachel played with the switches. If I stepped on one, it would swing down and then back up when I stepped off. They both did this, both made noises as if they were working,,,,but no movement
- one of them, portside, is up higher than the other and both are mostly in the position with the cylinder mostly retracted, not extended.

Question: To be sure that I am getting this correctly. My boat's tab switches have an up or down operation and the top of the switches say 'bow down ,,that means that pushing the top should cause the trim tab to lower into the water more,,,,right?

But anyway, they don't move at all unless I step on them. Sounds like a mechanical failure, right?

All in all tho, it was a good w'end. I changed my plugs and my boat starts and runs like a gem now and I also got my new 4-blade prop on !!! No more vibrations! So, all in all I guess I did okay for a dumb girl newbie

Thanks very much everyone - And I will hit it again next w'end to try and solve the stinkin' trim tabs.

I appreciate your help
Sarah

Edit: Oh yes. Almost forgot. My boat is a '95, so I am guessing that the tabs are original equipment (only 102 hrs on the boat when I bought it)

Re: Trim Tabs - Dead In The Water

Hi Sarah,

Ok, you have actually told me quite a bit from what you observed today.

First, you are correct, when you push the top of the control switch for Bow Down the Trim Tabs should lower into the water.

Secondly the actuators (rams) are most likely fine, as you got them to move down when you stepped on them. There are big springs inside of them that help retract the Trim Tabs and that is why the raised back up when you took your weight off of them.

Lastly, the fact that the system makes different sounds when trying to lower or raise the Trim Tabs, plus the fact that one seems not to be retracted fully tells me that the pump motor is working but the solenoid valves are not opening to let fluid get to the actuators to raise and lower them.

Simply put the system works by the pump running forward,making pressure to put the Trim Tabs down or running in reverse to bring the them up. There are two valves, on for the port Tab and one for the starboard tab that open and close in order to determine if one or both Tabs should move. The actions are controlled by electricity running the the pump in one direction or the other and opening and closing the valves.

In the troubleshooting I posted above it mentions that not enough voltage getting to the system can cause the pump to run but the valves not to open. When you tried to put the Trim Tabs down today the pump would labor against the closed valves and likely make a lower "groaning" noise and when you tried to bring the Trim Tabs up it likely made a higher pitched sound since no fluid was going anywhere.

So first things first, let's make sure that ALL the electrical connections are nice and clean. Including the back of the control switch and the connector near the pump #32 in the diagram. Pay particular attention to both ends of the black ground wire that goes to the pump, you can see that in the diagram too:



On a 15 year old system like yours it could be corroded where it attaches to the boat.

Then if that does not work I would like you to try step 3 in the original trouble shooting I posted.

Don't worry it's not hard to do and I will be delighted to walk you through the steps.

We will get you going!

Re: Trim Tabs - Dead In The Water

Thanks Tom,
I'm all fired up now, I can't wait to tackle them again.

pls stay tuned!

Re: Trim Tabs - Dead In The Water

LazyCruiser said:

Thanks Tom,
I'm all fired up now, I can't wait to tackle them again.

pls stay tuned!

Click to expand...

Very good, I keep Tabs (pun intended) on I-boats several times a day, so I will keep an eye out to hear what you find.

Tom

Re: Trim Tabs - Dead In The Water

That is what is called " Customer Service" for those not familiar with it.
I have the original Bennett Tabs on my 1984 Wellcraft and they sill work great.

Re: Trim Tabs - Dead In The Water

i had a similar experience with "insta trim" tabs

there was a rubber connection between the pump and motor and it had failed, so i could here the motor buzzing away but no tab movement, replaced the connection and away they went

its worth a look

Re: Trim Tabs - Dead In The Water

26aftcab454 said:

That is what is called " Customer Service" for those not familiar with it.
QUOTE]

+1 on that!

Click to expand...

Re: Trim Tabs - Dead In The Water

ewenm said:

i had a similar experience with "insta trim" tabs

there was a rubber connection between the pump and motor and it had failed, so i could here the motor buzzing away but no tab movement, replaced the connection and away they went

its worth a look

Click to expand...

That's likely not the case here (but it's a good idea to check all the hydraulic connections). The reason I don't suspect a failed hydraulic connection is that Sarah noted that the sound when trying to put the Trim Tabs down was different from the sound when trying to raise them. If a hydraulic fitting had failed the sound would be the same in either direction since the pump would not be building pressure against a "closed" system.

Re: Trim Tabs - Dead In The Water

Should I just plan on rewiring that ground wire? Like straight to the battery terminal? And maybe the hot (orange) wire also?

I'm also wondering if maybe my solenoid valves are the problem. Can they be purchased separately or do I need an entire HPU?


so many questions,,,,,,,,so little knowhow

Re: Trim Tabs - Dead In The Water

Sarah,

Replacing the ground wire is probably a good idea, and yes straight to the battery is good. Since the ground wire is usually aft and low in the boat it tends to get corroded more than the orange power lead which is up at the helm connected to the control. So just inspecting and cleaning the wires up there is all that is likely needed.

The connector in the four color wire harness back by the pump should be carefully inspected since it too lives low in the boat and can become corroded. If it looks bad you can simply cut it out and replace it with butt connectors if you like.

I really doubt that both solenoids have failed. It could happen, but they are simple and pretty bullet proof. We do sell them separately, but again, I doubt you will need to replace them.

All good questions. I am sure once you get back to the boat, inspect and clean the wiring and, if need be, do the tests I outlined you will either have a working system or I will be able to tell you how to best fix it.