Power trim leak 120hp '91 Force

[PaulO]

I used power steering hydraulic oil in the PTT reservoir. I noticed the ram weeps a bit of oil during retraction or extension. It seems fine if it is fully extended but not sure about partial extention. Is this oil the right type or should I use a thicker oil? I read in the clymers manual one option is to use 10W-40 engine oil. I don't really want to pull the thing apart.

Any advice please?

 

[RRitt]

Re: Power trim leak 120hp '91 Force

the best fluid is hydraulic oil. ISO32 is fine but if you can get 68 or higher that would be great. Second best is AW32. designed for all weather it contains some additives to stabilize viscosity. The additive strands can be torn by the pump gears resulting in loss of performance regarding bubbles and water. Third best is tractor fluid. This stuff is designed for farm tractors that use a common reservoir for both transmission and hydraulics. Although it contains additives they are done with rubber seals in mind and are not as harsh as the additives found in automotive lubricants.

But --- it may all be moot. 1991 systems have a tendency to bounce if the fluid is too thin. You may be stuck using non-detergent 30w just to keep your engine from bouncing.

regarding manual. non detergent motor oil used to be common. now it isn't. maybe 10-40 ND was a viable option in 1990. It isn't realistic in 2010.

 

[PaulO]

Re: Power trim leak 120hp '91 Force

You may be stuck using non-detergent 30w just to keep your engine from bouncing.

So I take it you are referring to the Hydraulic fluid? Please clarify.

What about the leak? Do I just put up with it? I'm not sure if it is only 1 or two O-rings in the cylinder and secondly how difficult it is to change them/it? It is very annoying.

 

[RRitt]

Re: Power trim leak 120hp '91 Force

30W ND is motor oil. It is roughly equivalent to ISO 96. Hydraulic oil like the stuff they used in bucket trucks and cranes is best. However, your year and horsepower of engine has a history of bucking if the fluid is too thin. I always use ND30 motor oil when I rebuild 89-91 Force. I have no way of knowing in advance what engine it will end up on and 30w is the only sure bet.

If it is a johnny, chrysler, or merc then i always refill with iso32 HO after a rebuild. unless the customer lives in the north pole - and uses his boat during winter ... then maybe AW32.

ram leak? how long you plan on keeping your boat? That seal was NSS (Never Sold Separately). as long as water isn't getting in then it may not be worth the high cost of fixing it.

 

[jkoppe73]

Re: Power trim leak 120hp '91 Force

There is a 3 ram o ring kit available on ebay for the Force trim tilt. not sure if it will fit a '91, but it included all the o-rings for the trim, and o-rings and wipers for the tilt, and the shock absorber for $20.00. you will need a spanner wrench , Armstrong #34-151 for the tilt and shock cylinders, and a 12 pt. 1/4" socket for the trim bolts. I used 30 wt. non detergent in the shock, and will run it in the tilt/trim system.

 

[RRitt]

Re: Power trim leak 120hp '91 Force

There is a 3 ram o ring kit available on ebay for the Force trim tilt. not sure if it will fit a '91, but it included all the o-rings for the trim, and o-rings and wipers for the tilt, and the shock absorber for $20.00. you will need a spanner wrench , Armstrong #34-151 for the tilt and shock cylinders, and a 12 pt. 1/4" socket for the trim bolts. I used 30 wt. non detergent in the shock, and will run it in the tilt/trim system.

that's me selling it on ebay. If your ram has a band collar then it fits. If your top port is drilled and threaded into the aluminum casting then the top seal does not fit.

That first Mercury made ram with cast port is a weird critter. It is half metric and half SAE. The top debris wiper does not comply with any industry standards that I can find. I have to hand craft a nylon shim when I rebuild one of those ... ugh :-(

 

[jkoppe73]

Re: Power trim leak 120hp '91 Force

Perfect fit, did my entire unit in about an hour, easier because it was off the boat,

 

[PaulO]

Re: Power trim leak 120hp '91 Force

RRitt

This is my trim unit. Is it the same as the one you had in mind? It has 5 screws around the perimeter so I guess it can be dismantled?

 

[RRitt]

Re: Power trim leak 120hp '91 Force

yup, that's the one. The tilt (tall skinny one on left in picture) is half metric and half SAE. I've been through hundreds of pages of hydraulic catalogs and never found the top seal for that one. All I have ever found is to use a nylon shim underneath the standard one in ebay kit. No exact fits anywhere.

 

[PaulO]

Re: Power trim leak 120hp '91 Force

RRitt

I was referring to the centre trim hydraulic and whether it is easy to pull apart and place an O-ring? It only seems to give up oil in transit but settles down when stationary. Refer start of this thread.

 

[RRitt]

Re: Power trim leak 120hp '91 Force

it is not unusual for the center (trim) ram to collect about 1/2 drop of oil every time it extends and retracts. Whether it is easy or difficult depends upon salt water exposure. If there is any white powder buildup on transom brackets then settle in for a long hard fight. If not, then it should be fairly easy.

 

[PaulO]

Re: Power trim leak 120hp '91 Force

RRitt

You sort of lost me . I have had the transom bracket apart since that photo was taken. It is all back together now. The only thing I wondered about is if I could take that trim unit apart and change an O-ring to stop the leak. I would say it passes approximately 1/3 of a teaspoon of fluid when retracting or extending. The reason for the photo is it shows 5 (3 visible) screws holding the unit together. If it is not a straight forward job I think I will leave it.

 

[RRitt]

Re: Power trim leak 120hp '91 Force

That is too much fluid. It should be looked at before you blow out the retaining ring and are force to buy new ram. The trim ram usually only does that when it has internal damage from saltwater. Whether or not you can fix it with a seal depends upon how much internal pitting it has. Using a square ring instead of an oring would help.

The five cover bolts stretch with use over the years. If your engine has any galvanic corrosion then they usually snap. Galvanic corrosion usually also fuses the cylinder sleeve into the housing body. Fixing a saltwater corroded trim system will make anybody's top ten list for "pain in the butt, wish I'd never started".

 

[PaulO]

Re: Power trim leak 120hp '91 Force

Ok. Understood. Thanks.

 

[bbalbano]

Re: Power trim leak 120hp '91 Force

RRitt

This is my trim unit. Is it the same as the one you had in mind? It has 5 screws around the perimeter so I guess it can be dismantled?

Sorry to change the topic but can the numbers that are stamped along the middle of your trim give you info on the year of the motor??

 

[bbalbano]

Re: Power trim leak 120hp '91 Force

Just to make sure i was clear Im talking about the numbers in the red box.

 

[PaulO]

Re: Power trim leak 120hp '91 Force

Good question. I don't know? Try and google them and see if you come up with anything, otherwise, you may need to find identifying features like gearcase water intake, anode postion and maybe engine particulars, run them past one of the experienced chaps on this forum to narrow the year of production.

 

[RRitt]

Re: Power trim leak 120hp '91 Force

I think that is the part number for a new swivel bracket.

If your paint is white then your engine is 1985 or earlier.
If you paint is blue and your trim motor is 3w then you have an 86 or 87.
if your paint is blue and you have a 2w then your have an 88
if your paint is blackish and you have a 2w with retaining ring manual release then you have an 89
if your paint is black and you have hex key manual release then you have a 90-91
if your paint is black and you have an eaton pump then you have a 92

his system in picture looks like a 1991 with the replacement pump sold by mercury in late 1990's. See how the tubing is not painted? That means it isn't the original pump/motor. The aftermarket replacement for Eaton is affordable ($180ish) so it was probably a Prestolite originally. That would make it a 1991 engine because i think the tilt ram would have a band collar if it was a 1990.