early 70's tilt trim

[perculator]

need help identifying some things and procedures for refilling and purging. can't find much info or parts on it. lucky that had a buddy come across one of these that fit my motor (73 evinrude 115).......best part is that the guy just gave it away.
i believe the tilt/trim number is 172655

the hole contains a bearing that looks to be pressure operated. a sending unit attaches over the hole. i'm not sure how it attaches or what it does. any help?

this is the sending unit.

this piston is in bad shape. the cover plate is off but i'm not sure how to get the rod out.
thanks for any info and help.

 

[nathanhooper]

Re: early 70's tilt trim

This "buddy" of yours sounds like a very, very nice guy. There are not many guys out there that are that nice, you should feel honored to have a guy like that around.

That said, that tilt trim looks like crap. You ought to break down and just buy a new unit and be done with it.

You have a 50/50 chance that its going to work when your done. I know an electrical engineer that might be able to diagnose the wiring issues you have if your interested. He might be able to figure out the hydrolic issues also, his grandfather was an engineer for the Manhattan project, and he used to work on a nuclear submarine. Just a thought...

 

[perculator]

Re: early 70's tilt trim

i thought it looked in decent shape....but i'm no expert. heck, i was just happy to find one.
maybe you're right....maybe i should just buy a cmc.

 

[RRitt]

Re: early 70's tilt trim

Too much rust. The bypass valves in pistons are a lost cause.
bead blast the things. soak them in a tub of ophospho acid. drill, tap, and plug the through holes.
you no longer have trim limit. Be careful not to lift your propeller up out of water with engine running.

Take the calco pump and beat it with a large sledgehammer until you get bored.
Then go buy a new volvo AQ290 for your pump. Get a slab of 1/2" aluminum and drill tap holes in it that matches the calco bolt pattern on one side and volvo on the other. mount volvo to slab and then whole thing bolts up like it was a calco. Only difference is that it actually works, is in stock at most every marina, and doesn't cost that much. Otherwise about the same as Calco.

If the tubing is good then great. clean it up and use it. If not, then go to the brakequip web site and find an automotive brake shop near you that is an authorized dealer. Have them make you new tubes from the brand name "easybend". It is CuNi tubing and will hold up better than stainless. Well, actually, 316 stainless is fine no matter what. It is all the other soft metals that get destroyed by SS 316's off-the-charts galvanic rating. CuNi doesn't destroy aluminum like 316 does. It is copper with a bit of nickel. Copper makes it galvanically inert and nickel makes it strong.

Put it all back together on the bench and make sure it goes up/down. Then go try it out on your boat.

 

[perculator]

Re: early 70's tilt trim

we've got the motor running....pretty confident the pump will work as well. found that part of the sending unit (broke) was keeping the piston from coming out.....it's out now. not sure what you are talking about with regard to the bypass valves. i'm thinking i can throw some rings in and be ready to test.
also is this (sending unit) for a limit switch or just a guage? the scem that i found show it goes to a guage. that said, i may try and find a part for that. the only piece that is broke is the plastic that screws into the cylinder. not sure if i can find one but i can try to find something that works.

 

[RRitt]

Re: early 70's tilt trim

the hole in the piston is a bypass valve. there should be a ball bearing and a spring. when you hit a sandbar the ball bearing gets pushed up and your motor lifts before breaking in half. if you back into a tree another ball in the other direction pops open. Most Prestolites had 2 bypass valves for bottom and one for reverse. Yours looks like one and one.

rust attacks the springs and makes them weak. Your piston rust looks so bad that spring might just break and then you have no lift at all in any direction.

 

[perculator]

Re: early 70's tilt trim

what kind of spring? i didn't see one when the ball bearing came out. if i just plugged the hole would this thing operate? the piston does have windings on it that look to engage the bearing.....i'm guessing that was for a guage.
i appreciate your info.

 

[perculator]

Re: early 70's tilt trim

searched for the spring and it's either disintegrated or missing. think i may just plug it and test it out. anybody know bleeding procedures for filling the res?