Who's ready for the first dumb question of 2018?

[Mile2885]

Just put the lower unit back on and noted when taking it off the previous shop didn't line up the marks on the trim tab. Can't imagine that a 2" tab would make any performance difference if it was off. Should I just line the marks up like the service manual states and forget about it?  Thanks.

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[Fisherdv]

Yes, line up the marks as stated in the manual. When you take the boat out, note wether the boat pulls to the left or the right while on plane with light hand pressure on the wheel. If it pulls one way or the other you can make small adjustments to it afterwards

[StreamFixer]

That little trim tab counter acts the rotational torque being generated by prop rotation.  If it is out of adjustment (or just plain gone) you will be constantly fighting the wheel when you should be just gently guiding it.

Your call...

StreamFixer

[Fisherdv]

Basically you want to adjust that tab so when on flat water and on plane you can let your hand off the wheel, (very briefly) and the boat will stay straight. CAUTION though, do not let go of the wheel completely if you feel a pull while holding the wheel lightly, if you do the boat could quickly turn one way or the other until that tab is adjusted correctly

[HemiGTX]

That's not a dumb question.

The trim tab makes a huge difference.  They become difficult to properly adjust with hydraulic steering, because you can't feel the effects due to lack of feedback.

[BruceL2_Fish]

I have mine marked so whenever I remove it I know where it is supposed to be positioned when I re-install. 
As Hemi said not a dumb question at all.

[Mile2885]

Looks like the previous shop had it pointed straight with direction of travel. I'll try it and keep an eye on how it handles. Looks like when the factory marks are lined up it appears to have a slight angle to it. Figured  it was to offset prop rotation. Thanks for all the replies.

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[Salmon King]

I have mine marked so whenever I remove it I know where it is supposed to be positioned when I re-install. 
As Hemi said not a dumb question at all.

WHAT HE SAID!

[La-Z-Buoy]

As others have stated so well: it makes a huge difference when not correctly positioned. 1/4 inch rotation makes all the difference. Had to adjust my last two motors. Easy to do.

[wedocq]

  I would agree with what was said. but, before making any adjustments, I would first test drive the boat to see if you notice any performance issues. If not, I would just leave it. If so, make the adjustments accordingly.
-Shawn

[Threeweight]

All boats will need that tab adjusted slightly to track true on plane.  It's fairly predictable based on whether you have a right or left hand rotation lower unit/prop.  Your dealer likely adjusted it to their best guesstimate when they installed the motor.

[Danno]

All boats will need that tab adjusted slightly to track true on plane.  It's fairly predictable based on whether you have a right or left hand rotation lower unit/prop.  Your dealer likely adjusted it to their best guesstimate when they installed the motor.

And the feedback through the steering wheel would be different on a cable steering system versus hydraulic.

[GHMariner]

That's not a dumb question.

The trim tab makes a huge difference.  They become difficult to properly adjust with hydraulic steering, because you can't feel the effects due to lack of feedback.

With hydraulic steering, they can simply be removed. The purpose of the trim tab is to make the engine easy to steer, at the cost of efficiency. Hydraulic steering eliminates the feedback, and therefore the need for the tab.

[Mile2885]

That's not a dumb question.

The trim tab makes a huge difference.  They become difficult to properly adjust with hydraulic steering, because you can't feel the effects due to lack of feedback.

With hydraulic steering, they can simply be removed. The purpose of the trim tab is to make the engine easy to steer, at the cost of efficiency. Hydraulic steering eliminates the feedback, and therefore the need for the tab.

Yep- I have hydraulic steering. I'll see if I notice any difference.

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[Ko Ho]

Correct me if I'm wrong, but I believe my trim tabs are part of the anticorrosion zincs. It looks like the one in the picture is also. If that's the case it seems like you'd want to leave them on.

[DevMah]

That's not a dumb question.

The trim tab makes a huge difference.  They become difficult to properly adjust with hydraulic steering, because you can't feel the effects due to lack of feedback.

With hydraulic steering, they can simply be removed. The purpose of the trim tab is to make the engine easy to steer, at the cost of efficiency. Hydraulic steering eliminates the feedback, and therefore the need for the tab.

I beg to differ...
I have hydraulic steering and it dose make a difference  (Factory Sea Star)
First of all it corrects the prop torque
Second it help help the boat steer on center.

I had to adjust mine as with the dealer install ,one side was easy to turn the wheel (one finger) other side was far stiffer. The faster I went the more difference i felt.

I also had to keep correcting the steering so that the boat went straight while on plane.

I would mark where it is located now before doing any changes.

And yes they can be a part of the anti-crossion system.

May not be that relevant on small out boards but my 150 I could notice it.

Dev

[troll4fish]

On my last boat (starcraft Islander 19' with a I/O) after 4 trips up and a total of a month on the water my sacrificial trim tab was pretty eaten away so I replaced it and set it about a 1/4" tail left and the boat tracked straight and true and was easier to steer than my previous trip as the tab was pretty well gone on that trip. Makes a difference! I talked with a few locals at the Becher Bay marina campground that were bitching that their zincs cost them about $50 a month and replacing the motor trim tab was the most costly!
On my sea chaser 17 with the Merc 90 my trim tab shows very little corrosion from the last two week long trips to Nootka Sound. Must be because the electrolysis difference of the Aluminum StarCraft vs the Fiberglass Arima.