[Jimh23]

On my 1993 180 Diablo with 3.0 liter engine, I find it difficult to turn to the right in the 30 mph and higher speeds. Turning left is no problem. I do not have power steering. Any thoughts?

[WetWilly]

Hi Jimh23,

On many of the out drives there is a small metal fin sticking downward behind the prop. This is called a trim tab and it is used to off-set the torque of the propeller at cruising speeds by acting like a small rudder. The trim tab is also a sacrificial anode, so over time, it will corrode away, requiring replacement.

As a contributing member, you would have access to our growing library of manuals, brochures, wiring diagrams, and all sorts of information relevant to your Mariah, the stern drives and equipment. Here, you would find the proceedure for the trim tab adjusment. See as you're new to the club, I'll explain the procedure but please consider becoming a donor, it's the second best investment for keeping your Mariah in top condition, joining the club was your first!

Let's begin -

With the engine OFF and the boat at rest, remove the small plastic plug (blue arrow) from the top of the drive shaft housing and loosen the Trim Tab bolt (you will need an allen wrench for this).

Since steering to the left is easy, you will be adjusting the Trim Tab (circled in red) so the trailing edge is facing to the right when viewed from the rear of the boat. Make small adjustments and test the boat at cruise speed each time. It will probably take a few tries before you have it adjusted just right, so take your time and don't forget to install the cap when you're finished.

So there you have it...and now, to see what each donor level has to offer, Click here.

WetWilly

[indykoch]

Once again, WetWilly answers it correctly and with every single detail, including pictures!!! Nice job!

He's right, it's just the torque steer and is mostly corrected by that fin.

[Jimh23]

Thanks for a quick and accurate reply.

[WetWilly]

My pleasure Jimh23 and thanks indykoch, I have my moments......