Bennett Trim Tab Help

[journeyman]

Before the boat gets splashed in the spring, I think I will need some troubleshooting help from Bennett on this one so I need to know what size I have on My Marlin. No literature came with the boat. I've heard Bennett has top notch tech support.

I need to know:
Are they sized by the actual tab size and then paired with the pump/motor?
Is there a serial number on the pump/motor?

I know the location of the unit. Behind the access panel, port side in the mid-berth. Not low or leaking fluid.

At rest or at low speeds, the tabs extend and retract with no problem. Up on plane, the tabs only extend part/half way and no more. I'm thinking the pump can't overcome the water pressure under the tabs at speed, but why? Weak pump/power unit, bad hydraulic valves???

 

[Parthery]

Pop over to THT and either open a thread or send a PM to "Tabman". He is the reason for the legendary customer service.

 

[DennisG01]

Agree with the above about customer service (he's on Club Sea Ray, too). You can also call them and probably get faster/more direct service that way. However, your issue sounds like it's with the hydraulics and not the actual tabs. Meaning, the pump and rams (operation, anyways) are the same for all the boats - it's just the size/dimension of the tabs (and sometimes the length of the ram) that change. In other words, you likely won't need any specific information.

 

[wspitler]

Sounds like you may have air in the system. Bleeding may help. Check with Tabman!

 

[journeyman]

I sent Bennett an email detailing my problem. Hope to hear from them with some possibilities. Unfortunately, I'm on the hard so any solution can't be checked until I'm back in the water next spring.

I did some poking around Bennett's help section and found that their system is self bleeding, so air wouldn't seem to be the problem. We'll see what they say. If it's a piston problem, I'd rather replace before splash day.

 

[Curmudgeon]

If I tried even half tab on plane, I'd soon be a submarine ... :?

 

[DennisG01]

I sent Bennett an email detailing my problem. Hope to hear from them with some possibilities. Unfortunately, I'm on the hard so any solution can't be checked until I'm back in the water next spring.

I did some poking around Bennett's help section and found that their system is self bleeding, so air wouldn't seem to be the problem. We'll see what they say. If it's a piston problem, I'd rather replace before splash day.

The system doesn't need to be in the water to work. You can run it out of the water with absolutely no worry about damaging everything. Try holding the unit back with your hands directly under the lower hinge - in other words, simulate water pressure against the planes. If you're lucky, it will be enough to duplicate the problem.

Yes, it self bleeds -- as long as there is enough fluid in there. It's a small reservoir, affected easily by the boat being unlevel. Also, the reservoir is "full" when the fluid is at the proper mark on the reservoir bottle with the tabs fully retracted.

Something could be loose - allowing air to enter the system.

Try this - push down on the plane - it will take a little force, but you don't have to be Superman to do it. See if you can push it all the way down till you feel it reach it's "stop" (you should be able to do that). Feel for a broken internal spring - you'll know it if you feel it.

But I think it's kind of odd that both rams are physically broken. I suppose it could be a weak motor, but I think that's pretty rare with these. Are you 100% positive that there are no leaks? Look at the nipples where they go through the transom... look at the connections on the motor... look at the rams... follow the plastic lines...

 

[Tabman]

Before the boat gets splashed in the spring, I think I will need some troubleshooting help from Bennett on this one so I need to know what size I have on My Marlin. No literature came with the boat. I've heard Bennett has top notch tech support.

I need to know:
Are they sized by the actual tab size and then paired with the pump/motor?
Is there a serial number on the pump/motor?

I know the location of the unit. Behind the access panel, port side in the mid-berth. Not low or leaking fluid.

At rest or at low speeds, the tabs extend and retract with no problem. Up on plane, the tabs only extend part/half way and no more. I'm thinking the pump can't overcome the water pressure under the tabs at speed, but why? Weak pump/power unit, bad hydraulic valves???

I am here too.

How old is the system? We use the same Hydraulic Power Unit for all our "standard" systems.

It could be low voltage from weak or dirty electrical connections, the first thing to do is check and clean all of them, particularly both ends of the black ground wire at the pump.

The others are on target regarding the possibility of air in the system. That would be caused by a faulty pickup tube or other pump fault that would suck air into the system. Try taking the tubes of the front of the pump and have someone run the Tabs down while you catch the fluid in a container. It should come out in solid streams that clear the pump face with no spitting or foaming.

Lastly check to make sure the fluid is nice clear red ATF. If water is in it it will look "milky" and would cause the same issues.

Let me know what you find, Tabmanhelp@gmail.com

Tom McGow
Bennett Marine

 

[journeyman]

No leaks. The fluid level should be at the fill line while tabs are retracted, and it is. Not worried about running them while out of the water but if it turns out I need to replace/repair the pistons, I would much rather do it while it's on the hard. I am a diver, but... :lol:

Talk about legendary support, I sent them an email and in exactly 8 minutes, I got a response!!! :wow

Thank you for contacting us with your trouble.

We feel your hydraulic power unit maybe be dealing with a Low PSI or Voltage issue. Since you don’t have any visible leaks, then we need to check the HPU’s operation and ensure she is not sucking air. You do this by disconnecting the hydraulic lines at the HPU and try running the trim tabs down. You will need to have a cup &/or can to catch the ATF as it comes out of the HPU, but the main thing you are looking for is to ensure the unit is producing two solid streams of ATF out of the ports without any aeration at all. Please give this a try and let me know your findings as soon as you can!

We look forward to your reply.

I am impressed beyond belief!!!

The plan is to check the voltage and perform this test on saturday when I have an extra set of hands. I will also post my findings here.

Thanks to all

 

[journeyman]

Thanks Tabman, I saw your response after my above post. You guys are AWESOME!

 

[Tabman]

Sounds like M.J. Thomas answered your E-mail. He is a great guy and is on top of our E-mails!

Tom
Bennett Marine

 

[Parthery]

Tabman - I didn't realize you frequented this board....in retrospect I should never have doubted it. :goodjob

 

[journeyman]

Over the weekend, I had time and help to perform some tests. The temperature was 40 degrees Fahrenheit and I keep my batteries plugged in to a charger during the winter.

HPU unplugged-
both switches bow down - 14.2 volts at the blue, red and green terminals
both switches bow up - 14.2 volts at the yellow, red and green terminals

HPU connected-
hydraulic lines removed - https://youtu.be/73_21f8hpRQ - link to the test on youtube.
port side aerated, starboard side no air but not very strong (IMO)


Bad news from Bennett, the unit is sucking air, which isn’t repairable. The HPU needs replacement.
I hope Santa is paying attention!!! :lol:

I appreciate the help provided by them and kudos to Tabman for checking our forum to help those in need, I learned a lot and now have a few HPU parts if needed in the future.

 

[grady23]

I think TabMan must have a constant search engine running that looks for ANY reference to Bennett. This guy is the BEST I have ever seen for ongoing support. I have seen his posts on just about every boating/fishing forum I've ever been on. TOM.... Thanks for all the support you and your company provide for us fisherman and would-be captians. Your dedication will always be remembered when it comes time to purchase a new or even used boat. :goodjob

 

[journeyman]

New HPU came yesterday. Great price at BOE!!! Grady uses a different plug though. Will either have to replace the Bennett connector or the grady connector. whichever is easier.

 

[Tabman]

New HPU came yesterday. Great price at BOE!!! Grady uses a different plug though. Will either have to replace the Bennett connector or the grady connector. whichever is easier.

Jim,

If you send your name and address to me at Tabmanhelp@gmail.com we will be delighted to mail you a new Bennett type plug for the wiring harness, no charge.

Tom
Bennett Marine

 

[journeyman]

Tom, email sent. Thanks! One thing to cross off my to-do list.