Mercury 850 thunderbolt questions

[kdp89]

Hey guys, new to the site but i figured i would start with a question. I just picked up a 1975 merc 850 thunderbolt for a great price, but when i got it the controls were disassembled, so i have been trying to reassemble them into the proper working order. My question is how do you tell which throttle cable attaches to which plate inside the control box? it is an old mercruiser set of controls with the throttle/shift lever and the high rev starting lever. Also, does this motor have a trim motor inside or does it need to be hooked up to an outside pump? I know it probably sounds like a rediculous question to those of you who know, but give me a hand here! If it does have an internal trim motor, how do i go about hooking it up? the controls i have do not have any trim buttons on them. I hope my questions made sense and werent rambling too much. Thanks in advance!
Kyle

 

[carholme]

Re: Mercury 850 thunderbolt questions

Kyle:

Is this the type of control box you have?

http://www.crowleymarine.com/mercury-outboard/parts/640_28.cfm

Gerry

 

[Georgesalmon]

Re: Mercury 850 thunderbolt questions

Picture of trim pump 1979 1150. Trim pump is to the far port side, other pump is a washdown pump. If you have hydraulic cyclinders on either side of the motor on the transom it has a seperate trim pump mounted inside the boat and an operating switch seperate from the control. Post a picture.

 

[kdp89]

Re: Mercury 850 thunderbolt questions

Yep, thats the control box. And thats what i was afraid of. The Boat that the motor is on is not the boat it was originally on, and has no trim pump. How hard would it be to track down an aftermarket pump?

 

[kdp89]

Re: Mercury 850 thunderbolt questions

And does anyone have a pic of how to connect the pump to the motor? Sorry, im just trying to figure this thing out.

 

[carholme]

Re: Mercury 850 thunderbolt questions

Kyle;

Re the control box, lever, item 4 is for the throttle cable and lever, item 36 is the for the shift cable. Once you have it setup, the first cable to move when the shifter is moved is the shift cable.

The Merc Controls Newest manual used to be available online but I see that it has now been removed. I have a copy of it I can send you if you PM me an email address. It covers a large selection of the control boxes, yours included and though it does not have part numbers, it will show you how to overhaul the box. It is a large 25MB file.

Gerry

 

[Georgesalmon]

Re: Mercury 850 thunderbolt questions

I got my pump complete with hoses and hyd cylinders, switch with wire harness on Ebay. I'm sure I paid to much but I wanted it. $350. My motor did not have power trim and I'm just getting to old to lift it.

The control box is tricky to put back together. I replaced the cables and while apart completely cleaned and greased it. Had a heck of a time putting back together. And I got to see it together. Get all the help you can from Gerry.

The linc to my problem got me the help I needed.

http://forums.iboats.com/showthread.php?t=542320&p=3715668#post3715668