Prestolite tilt/trim pump wiring schematic?

[Silly Seville]

Hi Gang,

Well, as I sit here waiting for parts, I decided to monkey around with the non-functional trim pump on this engine. ('69 Johnson 85hp V4) I took apart the trim motor and soaked the armature/windings in solvent, freed the stuck shaft with a baby crescent wrench, and blew the mess out with compressed air. Applied a liberal amount of CRC electric contact cleaner and reassembled. Drained the old fluid out of the pump and refilled with fresh Dexron III ATF. Well, what do you know? The damn thing actually works! I couldn't believe it actually lifted the engine. I was so happy! :dance:

So you ask..."What is the problem Silly?"

The problem is, I don't know which way to wire it to send the engine back down. :facepalm: This is a (presumably) factory three wire harness with Red, Blue and Black. The pump must have been an aftermarket addition to this engine, because there is no provision for the trim pump wiring in the engine main electrical harness.

I hooked 12v positive to the BLUE and 12v negative to the BLACK. That combo took the engine up.
I hooked 12v positive to the BLACK and 12v negative to the BLUE. That ALSO took the engine up!

When I tried 12v pos to the RED and 12v neg to the BLACK...the motor ran, but the trim didn't move.
Similarly, when I reversed the connections...12v pos to black & 12v neg to red, same situation.

I'm hesitant to try any other combinations for fear I might permanently damage something. I figure if it goes up, I'm halfway there. I don't want to destroy it now that it wants to work!

I've searched all over the net for info...all I get is info about BLUE (Up) and GREEN (Down). That doesn't help me in this case since I have a RED in the mix. I'm only assuming this is a Prestolite because I can see that much printed on one of the trim cylinders. There are NO identifying marks on the motor/pump housing whatsoever.

Please help! :help:

 

[Chris1956]

Re: Prestolite tilt/trim pump wiring schematic?

Do you know if that is a two wire pump or a three wire pump? From the wiring diagram I saw, Johnny's had two wire pumps back as far as the mid 80s. What is your PTT unit from?

 

[RRitt]

Re: Prestolite tilt/trim pump wiring schematic?

that's a 3w tilt only motor. Also used on Chrysler. New chinese replacements run from $70 to $130. Original is substantially better quality and durability but for $70 you can't complain.

One popular wiring scheme was direct to switch. Another was to use a solenoid on "UP" and direct to switch on down. Being 3w the black is common ground. Blue is up and green is down. Because it has separate windings for up and down it is possible for the motor to work in one direction but not the other.

 

[Silly Seville]

Re: Prestolite tilt/trim pump wiring schematic?

Chris...I wish I knew the answer to what it's from. The backstory is, I just picked this engine up at an auction. Zero info on it initially; I am learning as I go along restoring it to running condition. It is a work in progress to see if it's a viable outboard for a future project speed boat. I know virtually nothing about outboards except what I've learned from this thread. http://forums.iboats.com/johnson-evinrude-outboards/ancient-johnson-85-v4-worth-effort-634661.html

 

[Silly Seville]

Re: Prestolite tilt/trim pump wiring schematic?

that's a 3w tilt only motor. Also used on Chrysler. New chinese replacements run from $70 to $130. Original is substantially better quality and durability but for $70 you can't complain.

One popular wiring scheme was direct to switch. Another was to use a solenoid on "UP" and direct to switch on down. Being 3w the black is common ground. Blue is up and green is down. Because it has separate windings for up and down it is possible for the motor to work in one direction but not the other.

Thank you RRitt...that helps me move in the right direction. IS this in fact a Prestolite? And why do I have a red wire instead of green? Can you identify the model designation for me based on looks alone as I have no numbers to search for?

By saying "tilt only" how does that differ from "tilt/trim"? I am only familiar with sterndrives, so my vocabulary is limited with outboards. I thought that any tilting function is trimming as well? How are the two different?

 

[tblshur]

Re: Prestolite tilt/trim pump wiring schematic?

Silly Seville if i understood you correctly the motor ran when you put 12v pos to red and neg to black if so your problem is probably a stuck hydralic valve . you might try to loosen your manual release screw and let it down then connect pos to blue and neg to black run it back up and do that a few times to get it freed up good luck someone may have replaced the wire thats why you have a red:joyous:

 

[Silly Seville]

Re: Prestolite tilt/trim pump wiring schematic?

Thanks for your input tblshur! Yes, 12v positive to red and negative to black made the motor spin, but the trim sat motionless. I have powered the trim up and let it down manually about 10 times thus far. Still no movement from the red wire. I will keep trying. BTW, the red wire is definitely factory or original to this harness. The harness is complete all the way into the motor can. I really hope someone recognizes the model number of this pump.

 

[tblshur]

Re: Prestolite tilt/trim pump wiring schematic?

Silly Seville if you look on marine enjine.com dia. for model 85etlr76d it looks a lot like yours year model 76.

 

[boobie]

Re: Prestolite tilt/trim pump wiring schematic?

Could you post a pic of the whole unit and the back of the motor ??

 

[RRitt]

Re: Prestolite tilt/trim pump wiring schematic?

probably one of these. used on both chrysler and omc with minor differences in oil pipes.

TILT ASSEMBLY (F5H144) FOR FORCE TRIM & TILT MODELS 35 THRU 75 HP

 

[boobie]

Re: Prestolite tilt/trim pump wiring schematic?

So this must be a tilt only ??

 

[RRitt]

Re: Prestolite tilt/trim pump wiring schematic?

So this must be a tilt only ??

I think has to be tilt.
All the older Evinrude trim I have seen require a larger fluid reservoir. The left ram only has one tube and fills from bottom. So a lifted system needs a LOT more fluid than a lowered one. the small trim motor with the small reservoir would run out of fluid.

The tilt system, on other hand, fills fluid both above and below piston. Instead of filling the cylinder it is just pumping the fluid in a big circle. So it can use a much smaller reservoir. Like the one in picture.

 

[Silly Seville]

Re: Prestolite tilt/trim pump wiring schematic?

There are two cylinders, but only the starboard side has the hydraulic lines going in at the top and bottom The port side is a shock absorber...its part # is 383617

Notice how the shock absorber is the same color as the engine, and the hydraulic cylinder is the same color as the pump/motor assembly? That's why I believe this was put on sometime later.

Can someone educate me on the physical differences between tilt only vs. tilt/trim? What does a trim do that tilt doesn't. I'm a sterndrive guy, so for me, they are one and the same. Drive goes up/drive goes down. Stop and start in any position I want. Isn't that what this system on the outboard is for?

Oh yeah, it did come with a long bar that slides into the holes on either side of the brackets and has a locking link to prevent it from backing out. I assume that bar is for manually raising/lowering the trim into a static position.

 

[Joe Reeves]

Re: Prestolite tilt/trim pump wiring schematic?

Your system is "Tilt" only, used to simply lift the engine out of the water when beaching etc. It does not and will not hold a tilt position while underway. The wiring schematic is as follows.

 

[Silly Seville]

Re: Prestolite tilt/trim pump wiring schematic?

Thank you Joe!

 

[F_R]

Re: Prestolite tilt/trim pump wiring schematic?

It has been many years since I've worked on one of those, but I do remember that particular type of pump had much trouble with blowing a gasket inside the valve body. Just what the result was, I don't remember, except it wouldn't pump correctly. Probably up, but like I said, I really don't remember. There was a gasket kit for them, but probably long ago obsolete. Besides, the kit was sort of a secret, not listed on the parts diagrams.

EDIT: BTW, the solenoid was only used on SOME models, mostly Power Trim & Tilt where more force (amps) was needed to tilt against the thrust of the prop.

 

[Silly Seville]

Re: Prestolite tilt/trim pump wiring schematic?

Thanks F_R.

That looks like it exactly except mine does not have the "latch release assembly". My pump only has two hydraulic lines. I can make it go up repeatedly with the pump with hardly any effort over and over, but when I reverse the voltage (12v to red) the motor spins nice and easy and will continue to do so indefinitely, but no movement from the cylinder. I guess I have a dud. Oh well, maybe it can be useful to someone for parts. Or if I mount it on a boat, I can always use the manual release valve to drop it down. (Keep screwdriver on a lanyard!)

 

[RRitt]

Re: Prestolite tilt/trim pump wiring schematic?

i wud guess something wrong with the directional actuator. Replacement check valves are not available. But your check valves are rebuildable if they have a 9/16" diameter. If yours have a 1/2" diameter then you have to replace valve body. New chinese VB cost $70-80 each. They are not anywhere close to original quality.