Trim Tab ? I think?

CJY

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I have a 1989 Johnson 70 hp. On the lower unit there is what the manual calls a trim tab. It is adjustable to 360 degrees on the horizontal. My questions are 1. What exactly does this little device do and 2. How should I set it?<br /><br />Any help is truly appreciated,<br />Thanks,<br />John
 

Walker

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Jun 15, 2002
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Re: Trim Tab ? I think?

Its there to counter act prop torque on the engine steering. Try it with the back edge of the convex curved side dead center to the rear. <br />Now take a ride. If your steering wants to pull to the right then turn the trim tab a little to the right. Take another ride. etc. etc. etc.
 

CJY

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Re: Trim Tab ? I think?

Thanks Walker, that is exactly what I will do.<br /><br />John
 

Walker

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Re: Trim Tab ? I think?

Not sure if I was very clear. If it pulls left move it the other way.
 

CJY

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Re: Trim Tab ? I think?

I may have tried going in the wrong direction initially, but would have quickly figured it out. Thanks for the correction though. Any idea why it has a radius and is not just straight? What would happen if I removed it altogether and the boat did not pull in either direction? Is this a bad idea?<br /><br />Again thanks,<br />John
 
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