Motor won't stay up....advice needed please.

[CharlieZulu]

Brought my motor all the way up yesterday and put the boat on the lift. Noticed after an hour or so the motor was all the way in the down position
I thought it was a senior moment, and I returned the motor to the trailering position and lo and behold this morning she's all the way down again.
I've never investigated this before, so have something to learn about how power tilt/trim actually works.
Fisrt thing I checked was the fluid level for the hydraulic pump, and I cannot even see any fluid in there... obviously the first thing to do is top this up.

This is an old motor - Merc 90, S/N 0B17449, I think '89 vintage or so, and is a new motor for me (service history unkown)

 

[Dave1027]

Re: Motor won't stay up....advice needed please.

Mine does the same (mines an '88 so I guess this is what happens to them after 20 years).

I was told the pump is leaking and the only thing you can do is to replace it as a unit because it cannot be repaired. They cost between $300 and $500.

I'm living with mine that way. I have a transom saver on mine to keep it up while on the trailer. Overnight on the lake I wedge a block of wood in the bracket. The only part that bothers me is while cruising I have to trim it back up every 5 minutes or so. Oh well. That's a smaller price to pay.

 

[hkeiner]

Re: Motor won't stay up....advice needed please.

Do not be too quick to replace an expensive part untill you are sure it is the problem. There are various possible causes for the motor to leak down and some fixes are relatively cheap to perform if you can get the replacement parts. The below guide might help.

http://forums.iboats.com/attachment.php?attachmentid=20934&d=1228687846

 

[Dave1027]

Re: Motor won't stay up....advice needed please.

Hkeiner,

My book does not show how to remove the manual release valve to check it's o-rings. Have you done this? Do simply keep unscrewing? Will fluid run out?

 

[instlr]

Re: Motor won't stay up....advice needed please.

Mine has a little e-ring or clip behind the opening that keeps it from coming all the way out. If yours is the same, reach behind the starboard side bracket with a set of needle nose pliers and pull the clip out, then it should come all the way out.

 

[ChrisfromVT]

Re: Motor won't stay up....advice needed please.

Bleed the system before checking anything else

 

[hkeiner]

Re: Motor won't stay up....advice needed please.

I would strongly suggest that you get an OEM Mercury shop manual before you do any disassembly of the trim unit. A shop manual will have step by step instructions, parts diagrams, troubleshooting guides, and other imporatant information. I would not consider working on a trim unit without a manual for guidance. These trim units can seem a bit complicated to those that do not know how they work or how to disassemble them correctly.

Just my thoughts....

 

[CharlieZulu]

Re: Motor won't stay up....advice needed please.

Yep, I have two manuals, but I think I will start by actually adding transmission fluid to the pump reservoir!!! I can't see anything in there.

will report back in a day or two.

chriis

 

[Blevins]

Re: Motor won't stay up....advice needed please.

There is also (I BELEIVE) a manual release bolt on the port side of the hydraulics that merc made with PLASTIC! These have been known to rot out or dissolve over time. On my 1998 225 mine had to be drilled out because an air bubble got into the system and it wouldnt trim down. The plastic piece is cheap like .20 cents. give that a check

 

[CharlieZulu]

Re: Motor won't stay up....advice needed please.

Well, here's the update on this..... I topped up the fluid but it didn't take much and the sagging problem is still there.

I guess I will live with it until the boat comes out of the water and it's on the trailer for the winter, and I can service the system.

 

[MCotherman]

Re: Motor won't stay up....advice needed please.

Well, here's the update on this..... I topped up the fluid but it didn't take much and the sagging problem is still there.

I guess I will live with it until the boat comes out of the water and it's on the trailer for the winter, and I can service the system.

I just rebuilt my trim system (single ram mercury 115). $1.98 in o-rings (replaced every o-ring in it) and it works like new. Mine was leaking down under load. Very simple (for me) to work on.

 

[RRitt]

Re: Motor won't stay up....advice needed please.

slow bleed down from full up is almost always the forward check valve getting old and deteriorating. The wise course of action is to live with it until you are prepared to do a full system rebuild. You should not stow or tow your engine with it resting on the hydraulics. There is a signifacant risk while towing that a big pothole could pop open a bypass valve and allow you prop to drag the pavement. When stowing, you can significantly extend the life of your system by relieving internal pressures. Mercury is notorious for using cheap orings with cheap ATF fluid. The crystallize under pressure. Many of their trim systems only last 15 years when they could have lasted 30 without the effect of cheap ATF+pressure. You should always brace your engine up and relieve internal pressure when your boat is not in use.

If you do a halfway rebuild on a trim system then it is almost a sure thing that you will get to do it again. All of the rubber throughout the system is exposed to the same fluids and the same pressures. Water intrusion in one spot is usually circulated to all spots. It is very rare for one part to break without several others being close behind. Duct tape repairs usually cost more in the long run by allowing expensive parts to become damaged.

 

[hkeiner]

Re: Motor won't stay up....advice needed please.

relieve internal pressure when your boat is not in use

I like that advice, but how does one relieve internal pressure during storage? Is the motor moved to the the "down" postion and then the manual release valve slightly loosened and kept loosened during the entire storage period? Alternatively, is the motor moved to the "up" position, the manual release loosened, the motor manually lowered, and the manual release valve retightened? Either way, I presume the motor is stored in the down postion so that the shiny trim pistons are not exposed during storage. I always appreciate good advice...

 

[RRitt]

Re: Motor won't stay up....advice needed please.

lower the engine onto the trailering bracket, latch, or 2x4 piece of wood. That is enough.