Trim pump question

[redneck joe]

Slowly drops when on trailer, quickly drops when in use. Manual states to check fill i need to loosen vent screw specifically two turns then the end of the instruction tells me to leave screw open. Why would I have to loosen if it is already loosened?

 

[Chris1956]

That motor should have the PTT pump/reservoir in the boat. The vent screw has no impact on the PTT pressure. It should be a bit loose to let air in/out of the reservoir.

When those systems leak down it can be the control valve or the piston seals in the PTT cylinders. Most often it is the piston seals. PTT cylinder rebuild kits used to be available.

Here is the parts list. Maybe you can find a rebuild kit somewhere. Also be on the lookout for the special tool to install the piston into the PTT cylinder.

Mercury Marine Outboard 1982 50 [ELPT] 1050622 [1050622] - Parts Lookup | Crowley Marine

View parts diagrams and shop online for 1050622 : Mercury Marine Outboard 1982 50 [ELPT] 1050622. Offering discount prices on OEM parts for over 50 years. FAST $4.95 shipping available.

www.crowleymarine.com

 

[redneck joe]

@Chris1956 thanks.

I do have original owners manual and went thru yesterday. I've found the rebuild kit on ebay, 100 bucks each but it is what it is. I do not see any reference to the special tool - is it required or just nice to have?

I've had the boat at couple three years and just this spring got the manual. After a year of it dropping i decided to top off the fluid which in reading the manual yesterday is a no no so when I was running thru the steps I left the fill cap off and during the cycling it purged to the proper level. The drop is slower now, back to originals I'm assuming the extra pressure from being overfilled was making it worse. Or could just be wishful thinking.

There is a pressure test kit listed in the manual and again ebay for 300 bucks which I hate to spend on an tool I'll use once before I'm dead. In interneting and your confirming it is usually the cylinder in your opinion should I just get the repair kits and hope for the best? Also if it is the pump unit, it appears that Amazon has replacements?

Last thing, would you happen to have a link to the rebuild process?

 

[Scott Danforth]

Joe, if your PTT cylinder seals are going / gone, it will bypass as you describe.

hydraulic cylinder seals last about 15-20 years and cylinders need to be re-sealed.

pull the cylinder and rebuild it. seal kits is cheap. I get my kits from five star. They also sell the pin spanners needed if you want to do a one-stop shop.

post pics, pulling the cylinders if you run into issues, feel free to reach out.

 

[Chris1956]

I doubt filling the reservoir had any bearing on your PTT system. The reservoir is open to the air and self-bleeding. You should be using auto trans fluid or SAE 5W-30 motor oil, whatever the unit already has.

The special tool is kinda like a funnel which has a small taper. It compresses the Teflon seal on the piston, as you push it into the cylinder liner. I never had the tool and after ruining the Teflon seal trying to install it, I had a Merc Dealer install a new Teflon seal for me, using his special tool.

It is likely only one piston seal is leaking, however, there is no easy way to tell as they are connected together. You could remove the hydraulic lines for one cylinder at the control valve and plug the control valve and test the other cylinder for leak down. The plugs are standard NPT I believe.

The hydraulic lines to cylinder threads are pretty fragile. They strip easy, so be real careful when removing or reinstalling. You have the cylinder bleeding procedure? They are not self bleeding.

Scott sounds like he has a line on the rebuild kits.

 

[redneck joe]

Thanks Scott, I did try them as you recommended, sent a pic of the pump unit and they do not work on them. I just did an input of the nla rebui,d kit for the rams and no results. Looking briefly at the website looks like they only go 88 forward. Not sure about the spanner tool.

 

[Chris1956]

The Spanner tool is easy. I made one out of 3 bolts and two 6" pieces of angle iron. They are also avail on the internet for a few bucks. You need the dia of the holes to order the right one.

The rebuild kit has the teflon seal and a bunch of orings and a wiper for the trim rod. The only leak I ever had was from the trim rod oring.

 

[redneck joe]

Here is the ram.

Chris, I assumed that it would just be a matter of knowing what rings to get so thought about just buying one and matching after that but the kit shows a brass looking peice as well however my assumption is that would be a mostly non wearable part and given the slow decent would tend to be a rubber piece rather than brass. What hole would I need the diameter of?


Scott i will reach back out to five star (Port Richey, correct?)

 

[Chris1956]

Joe, unlike most PTT units, yours likely has the teflon seal, vs a rubber oring on the brass piston. The parts diagram shows it as item #10, piston seal.

Also notice, that the cylinder liner is removeable and the piston unbolts from the trim rod. That is very useful when the piston seal is good but one of the orings is leaking. You can leave the piston in the cylinder liner, and replace the orings.