Trim, Tilt, and Jack Plate Mounting Questions

[jddenham]

Hello all,

I just received a 1975 merc 1500 to replace my 1976 merc 500. The bigger motor has trim/tilt and smaller does not.

My boat has a 16" transom and the cav plate of the 500 is about 1-2" below the keel.

Knowing that the 1500 will also hang too low I purchased an adjustable setback/jack plate for optimum performance.

My questions are concerning the tilt/trim operation. There are three buttons inline on the control. I thought all the feature did was tilt up or tilt down the motor, but why 3 buttons instead of 2?

Does this system also offer vertical motion straight up and down so that I wouldn't have to use the jack plate?

How do the three buttons work?

Any thoughts or comments?

The boat is a 1969 16' Fiberform V-hull, rated for 125HP.

Thanks in advance!

James

 

[Capt. Crunch]

Re: Trim, Tilt, and Jack Plate Mounting Questions

I haven't hooked up my trim/tilt on my 150 yet, but on our past boats one button controlled the trim up, one button controlled the trim down, and the third controlled the trailer tilt. In other words, the trim up only reached a certain angle/height. The trailer button raised it the rest of the way to the maximum angle/height (like you would want it for pulling your boat out at a ramp to place on a trailer). The trim down button lowers from max up trim position as well as trailer position.

 

[jddenham]

Re: Trim, Tilt, and Jack Plate Mounting Questions

OK, so up and down buttons for while in the water and under operation, and an additional up button to raise completely. Makes sense. Looks like I will be using the jack plate.

Since it sets the motor back 6 inches or so, I was going to start out at 2 inches above the keel with the cav plate. Sound like a good starting point?

Thanks!

 

[Chris1956]

Re: Trim, Tilt, and Jack Plate Mounting Questions

Just so you know, The middle button will trim the motor. To tilt the motor, you push both middle and top buttons at the same time. There is a trim limit switch located on the starboard trim bracket. When the motor is down, this switch makes a connection which allows the middle button to trim the motor. After some time, the trim position of the motor causes the switch to be open. Now you need the two buttons to make the motor tilt further. You can bypass the trim limit switch with a jumper on the trim harness, if the switch goes bad.

 

[jddenham]

Re: Trim, Tilt, and Jack Plate Mounting Questions

OK now the confusion - so I CAN trim the motor up(vertical movement only) ??

How much adjustment is possible? If I could get around 3 inches I wouldn't need the jack plate.

Why doesn't my manual talk about operation of the trim/tilt?? (cause it's a Clymer?).

Any more advice/input is welcome and encouraged!

James

 

[Chris1956]

Re: Trim, Tilt, and Jack Plate Mounting Questions

James, The PTT system on the motor will cause the motor to tilt forward. The powerhead will tilt forward and down, and the prop will tilt backward and up. This tilting is used to adjust the angle of the prop's "bite" into the water and to tilt the motor all the way up and out of the water for storage and beaching. There is no true verticle movement on your motor. A Jackplate can be used to move the motor verticle. There are power and manually adjusting and non-adjustable Jackplates.

 

[jddenham]

Re: Trim, Tilt, and Jack Plate Mounting Questions

I have a manual setback/jack plate on the way. I guess what I need to know is:

What is the difference between 'trim' and 'tilt'

How are the three buttons used exactly?

Thanks!

 

[Chris1956]

Re: Trim, Tilt, and Jack Plate Mounting Questions

James, If you motor's PTT system operates the way it should (nothing is broke), you will be able to trim the motor, while underway at any speed to achive optimum performance (either optimum speed at a high trim angle, or smoothest ride in rough water at a minimal trim angle), by depressing the middle button to trim up or the bottom button to trim down.

When you want to tilt the motor out of the water for trailering or mooring, (motor not running), push both middle and top buttons at the same time. Motor will tilt to max extent.

 

[gregtobin]

Re: Trim, Tilt, and Jack Plate Mounting Questions

My boat came with the hydraulic trim cylinders (uninstalled) for the '74 1150 Merc, but not the trim motor. A previous owner threw out the hydraulic motor. I can adjust tim manually by moving the trim set rod, but I'd like to get some kind of trim motor. Do I need to buy an expensive motor built for this application, or can I find a generic hydraulic pump? Does anyone know the length of the hydraulic cylinders so I can make sure that these are correct before looking for a pump?
Thanks!

 

[Chris1956]

Re: Trim, Tilt, and Jack Plate Mounting Questions

Greg, The PTT on your motor requires two trim cylinders, two cylinder mounting brackets, four trim hoses, and thru hull fitting for the hoses to pass thru your splashwell the trim pump motor and resevoir and control valve. If you do not have most of these items, you might like to buy an entire set off e-Bay or at some junk yard. The alternative is to buy an aftermarket T/T kit from CMC.

 

[gregtobin]

Re: Trim, Tilt, and Jack Plate Mounting Questions

I have the two cylinders and see where they mount. I'm missing the hoses, motor, reservoir, control valve, and electric controls. I'll have to find this stuff used as there seem to be some higher priorities that I'll need to deal with. Thanks for pointing me in the direction!
Greg