New guy here with 1973 Merc 115.

[happychef]

Hello, I am the FNG!
Now, having said that, I have a few stupid questions.

I just purchased this motor for my 16' Glasstream bass boat, but I am having a few troubles with the installation. Mind you, I am VERY mechanically inclined, as I wrenched on cars and built Hot Rods for 15 years. I am just lost for a moment with
this swap.

First, the transom measurement from the top to bottom of the boat is 22.5", and with the motor installed, the trim plate sits about 1" - 1 1/2" above the bottom of the transom. Will this be causing me any cavitation problems, or will I have to get the sawzall out and modify the upper transom?

Secondly, Tilt/trim.
The remote that I have seems to be about as old as the motor, but I wouldn't have a clue. It has tilt/trim switch, with a 4 wire plug (....) coming off the back side of it, as well as 3 stray wires with connectors on them, (2 female 1/4" spade, and 1 female 1/8" connector. The tilt motor set-up also has (2) 4-wire connectors on it, 1 male and one female, as well as the + & - cables.
Where do I plug the unit into?
What are the wires for that come from the remote?

I looked at this thing for hours tonight, but cannot figure out how to hook up this tilt motor.

Any help is GREATLY appreciated!!!

 

[Chris1956]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

Most boat transoms are standardized for standard motor shaft lengths. Try the boat/motor setup, prior to cutting the transom down. That motor will require at least four 3/8" transom carriage bolts to stay on the transom.

If the PTT is original for that motor it will be the two trim cylinders, seperate PTT motor and resevoir and 4 hydraulic lines connecting the two. You only really need three wires blue for up, green for down and red for power. The fourth wire is for the trim limit switch, installed on the starboard trim bracket. These usually break, so I would recomend you ignore it.

At the PTT switch panel, connecting red to green will make the PTT motor run in the down direction. Connecting the red wire to blue will make the PTT motor run in the up direction. I simply wired the middle button to the red and blue wires and the bottom button to the red and green wires.

 

[CV16]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

As for your height of the motor, my 16' Glastron CV16's motor sits about how you say yours does. I have no problems at all with it. I raised it up to that point, it gave me the best all around performance.

 

[merc850]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

Here's the wiring diagram.

 

[happychef]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

Thank you for the quick response!! I have heard nothing but good things about you guys here, and this just proved it!
I figured out the PTT wiring tonight, but your reply confirmed my theory, and it worked. Blue=up - Green=down.

My pump has 2 hoses attached. Both have flared fittings, but they are different sizes. Without looking at it, I want to say the one is 1/8" and the other 3/16"? Both cylinders on the transom mount have the same size fitting. So, I am not sure what hose goes where. I realize that the larger hose would be for trim up, but which cylinder is up, and which one is down? Or... am I missing something all together?

 

[happychef]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

As for your height of the motor, my 16' Glastron CV16's motor sits about how you say yours does. I have no problems at all with it. I raised it up to that point, it gave me the best all around performance.

Thanks for that!
I just realized, after I cleared my brain fart out, that my transom is notched anyway. So, I shouldn't have a problem.

 

[Chris1956]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

That PTT should have 4 hydraulic hoses. Both cylinders work together. Both push the motor up or down. Install the hoses where they fit, and you cannot mess them up.

 

[happychef]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

That PTT should have 4 hydraulic hoses. Both cylinders work together. Both push the motor up or down. Install the hoses where they fit, and you cannot mess them up.

Well, attaching the hoses where they fit was my plan, but the problem is that only one of them will fit. Both cylinders only have one 1/8" flare fitting on them. The pump has 2 hoses, one is 1/4" that will attach to either one of the cylinders, the other hose is 3/16", that will NOT attach to either one of the cylinders. So, I went ahead and found a different fitting that will allow me to attach the 3/16" hose to the other cylinder. I am going to hook them up today, and just see what happens.

I was at a couple of marine shops yesterday, trying to figure this out, but they were stumped as well. If it doesn't work today, I will post some pictures of what I got. Thanks ya'll!

 

[happychef]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

Well, I attached the hoses and the motor does go up and down... However, not really the way it is supposed to. If i hold 'trim up', the motor will go up, but then it will proceed to pump down. Almost as if the motor reverses once it reaches a certain point, but the motor itself doesn't reverse unless I trim the other way. The same thing happens when I trim down for too long.

Here is what I think, but I really have no solid basis for this answer.
I think the Merc is supposed to have 3 cylinders. 2 for going up (the 2 that I have), and one for down. I think there is supposed to be more hoses to the pump to support this, but I feel that someone may have done some 'engineering' to make it work half-assed just to get by.

I will post pics later, but for now, will someone please chime in as to what you think is going on?
Thanks!

 

[Chris1956]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

Crowleymarine.com will have pictures of the original PTT components. What you have described does not sound OEM to me, at least for that year motor. Maybe someone created a Frankenmerc?

The older motors had two trim cylinders. Newer high HP motors have three cylinders, and the newer lower HP motors have 1 cylinder. All trim cylinders work together. They all push up or push down together.

 

[happychef]

Re: New guy here with 1975 Merc 115.

Re: New guy here with 1975 Merc 115.

Well, I got it figured out. We have ourselves a Frankenmerc.
I am headed down tomorrow to Twin Cities OUtboard to get the right cylinders. The pump is ok, but I will need a couple of hoses too. It's a good thing that I made the seller sign a 7-day mechanical warranty on this motor.