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First, thank-you for extending yourself to be available here on THT and also for having such premium-level customer service.
Now the problem, albeit a small one. As the title indicates, I have a pair of your trim tabs. Generally, both tabs work exactly as designed. But the port tab will fully extend; the starboard tab is 2" short of full extension. Any ideas how to correct?
We make several different size actuators as well as some custom units for boat builders. To start narrowing down the possibilities can you tell me the make, model and year of your boat? Also do both Trim Tabs retract to the same position when they are in the full up position?
The boat is a 1992 Mako 261. And, No, the starboard tab will retract fully flush with the hull plane while the port tab retracts almost fully minus 1".
Take a look at the two actuators, there are molded rings at the bottom of the cylinder body. The standard actuator has 4 rings and a shorter one we make has 3 rings. Also when the Trim Tabs are fully retracted is there about 1" of piston shaft still showing below the cylinder body?
I suspect that one of the actuators was replaced at some point in the boat's history and it doesn't match the original one. Here is a picture to show you what I mean.
Yes, let's check the total stroke of each actuator. The standard stroke should be 2-1/2" can you tell me the travel of each piston shaft. Also are there indicators for the Trim Tabs installed?
Lastly if you push down hard on the Trim Tabs do the both bottom out "hard" at the end of their travel?
The starboard ram has a total throw of 2" while the port is 2.625 (2&5/8"). The aft portion of the starboard tab (plate) extends to 3" below the horitontal hull plane as measured from the chine while the port is 5".
There are no indicators for trim tab position.
And I feel no movement on the tab when pressure is placed upon them.
I'm Stan from Malaysia. I've recently purchased/taken over Chris's Mako 261 with the trim tab problem he had been describing to you earlier.
This is the described port (the problematic one) trim tab that has 2" of exposed shaft when fully retracted. It does not retract fully and flush with the hull unlike the starboard tab that has only 1" shaft exposed.
The stroke appears to be the same on both sides which explains why the starboard tab (normal) does not extend as far as the port tab (abnormal). The home position of the port piston shaft is an inch too far. Is there a way to adjust this?
The second question that I have, is the trim tab 9" (W) x12" (L) a wee small for the boat?
The Trim Tabs were custom made for Mako. And as you know they are made to fit into the pockets on the bottom of the hull. So installing a larger Trim Tab is really not an option without changing the configuration of the pocket or filling in the pocket and installing larger ones on the transom. Both of these would involve fiberglass work and be a bit expensive.
I am sure you noticed that there is a screw missing where the actuator attaches to the Trim Tab and it needs to be replaced.
It appears that the port actuator was replaced at some point with a standard one, since the ones used on that actuator were custom made to fit the pocket like the Trim Tabs. The standard actuator does not retract as far as the custom one, we could modify it to retract the extra inch.
I need to know, is the boat located in Malaysia? Let me know and I can advise you on the best course of action.
I would like you to take a picture of the other actuator please. If you took the same pictures of the starboard one as you did of the port that would be perfect!
The starboard actuator is the custom unit we supplied with the original Trim Tabs and the port one is a standard unit that someone added to the boat at some point.
The boat builder specified how far the actuator extended and retracted and we built it to those specifications.
It is easy to make the port actuator retract as much as the starboard one, and it is a good idea to do so the Trim Tab is flush when retracted.
Run both tabs fully up. Unscrew the Trim Tab from the lower hinge on the actuator. Grab the cylinder body and rotate counter clock wise to unscrew. There will be fluid in the cylinder so have a container handy.
If you look at the upper hinge (the part that remains attached to the transom when you unscrew the cylinder body) you will see a tubular black plastic "stop" (we call it the spacer) sticking down from in inside. This would be about 2" long and it limits the upward movement of the piston.
You can grab it and snap it out of the upper hinge (don't worry if some of the "feet" where it is glued in place remain). Then when you reassemble the actuator the piston will now retract 1" more.
Screw the cylinder body back in place and reattach the Tab to the actuator.
Run the tabs up and down 3 – 4 times to self bleed the system, top off the reservoir with ATF if needed. The actuators will now retract all the way up to the cylinder body like the other side,
If you want to make the port side extend the same as as the starboard you will need to purchase a standard Bennett actuator, part # A1101A. Once you have the standard actuator you can take off the upper hinge and screw it on to the upper hinge that you removed the spacer from on your transom and both actuators will now be the same.
You can contact our Malaysian distributor to purchase the standard actuator, or perhaps you have someone purchase it in the US and ship it to you.
Tom, thank you for such a personally directed, comprehensive and detailed reply.
Would it be better to shorten/cut the spacer to 1", the distance I want it to retract further, rather than to completely snap the whole (2") off. Will it over retract? I can see that it may be difficult to shorten it.
I apologise for my inaptness, what is ATF?
With regards equal extension of both tabs, which I suppose is not as crucial, the standard Bennett actuator/Ram part # A1101A, is to replace the port (standard) or starboards (custom) side actuator? Will it require the spacer modification?
Thank you for clarifying.
Wishing you a Happy Christmas and a fruitful New Year.
Stan.
Last edited by stan2538; 12-23-2010 at 09:04 PM.
Reason: Extra question.
You can try cutting the spacer, but it will likely snap iut when you cut it. If you were in the US we could send you an upper hinge with a 1" spacer, but I doubt the Malaysian distributor has one. The Trim Tab will probably bottom out on the hull (it looks like the starboard Trim Tab already does if you look at the left side of it).
I agree that having them both retract fully is most important.
The # A1101A would be to replace the starboard actuator body, you would unscrew the old cylinder body from the upper hinge of the old one (which has a 1" spacer) and screw the new body on to it. But I would just modify spacer on the other one first and try running the boat.
I also wish you a Happy Christmas and a Prosperous New Year.
Tom, you are right about the starboard tab bottoming out on the hull, there are deep tab impressions on the gelcoat where it comes into contact. I will attempt to modify the spacer on the port side first.
I may want to have the hinge with the customised 1" spacer on both sides, lower hinge/tab screw (missing) and even the #A1101A but I would want to pay for those and any S&H. USPS services Malaysia reliably or send it to a friend in the US. Thanks.
Ok Stan, let me know how it goes. We can send new upper hinges with 1" spacers at no charge within the US and you can purchase a new A1101A through a dealer here in the US and then perhaps your friend can have them shipped to you.
Hello Tom, could you kindly do that, send the upper hinges with customised 1" spacers? Would that be 2 units? I will PM you "chrisrack"s address, he is willing to forward them to me in Malaysia. I have ordered a standard A1101A from a US supplier. If there are any charges on your side, let me know. Thanks. Stan.
Starboard Tab does Extend as Far as Port Tab 
