Steering and trim tab question.

[MBJJ2369]

I have a new to me motor on my boat. It is a 1991 Johnson 48SPL. The boat is a 1988 Blue Finn 15 ft. long. The previous motor was a Force 50hp. When at full throttle the boat tracks straight, but it is extremely hard to turn to the right. Turning to the left is extremely easy, you could turn it left with a feather. When the boat is at idle it turns left and right with the same amount of effort.

If the motor is tilted all the way up and standing behind it, the trim tab is pointed at the 2 oclock position. Would adjusting the trim tab make it easier to turn right?

 

[Lightwin 3]

Yes it will. Put the tab back to center and test. I suspect you may end up in about the 10-11 O'clock position to gain "nuetral" steering.

 

[MBJJ2369]

Thanks, I hope I can give it a try tomorrow.

 

[89retta]

Put it at the 10 o clock and it should be easier. Also are you sure the new motor is not sitting to low. Sounds like to much of it is in the water. I had the same problem on my old boat when I went from a 115 mer to a 115 Johnson

 

[MBJJ2369]

Not sure if it is sitting too low or not. I had a boat mechanic put it on for me. Is there some way to measure where it is supposed to be?

 

[MBJJ2369]

I found out what I needed to as far as how high or low it should be mounted

 

[89retta]

I found out what I needed to as far as how high or low it should be mounted

And is it mounted at the right height ?

 

[Fed]

Start at 12 o'clock, OMC trim tabs come with a built in bias to the Starboard.

I like to do it in order...

Make sure the Anti Vent plate is level with or slightly above the bottom of the hull.
Set the trim tab (OMC) in the middle. (Mercury slightly to the Starboard.)
Balance the boat front to back & left to right.
Go for a ride & find the trim position that gives you 3-5 degrees at a fast cruise.
Then adjust the trim tab to give you even steering at fast cruise.

 

[MBJJ2369]

I havent had a chance to go look. Cant keep the boat at the house where I live.

 

[MBJJ2369]

I checked the boat out today and the Anti Vent plate is approximately 2 inches above the bottom of the hull.

 

[MBJJ2369]

I took the boat out yesterday and moved the trim tab to the 12 o'clock postiion. The boat ran straight and true and turning in either direction was equally easy.