I/O Leg won't go all the way down.

[Smiks]

I recently acquired a boat I've been working on. I was told it was about a 1980, 120hp Merc. I believe the serial number is 2364043.

It had been sitting for 7 years, so needed some R&R. Did some maintenance to the engine and got it running. When I went to test out the trim, I was able to get it to trim all the way up, but when I go to trim down, it only goes down about a 1/4 of what it should. From Center to Center on the cylinders bolts I can only get it to go down to 24".

Just wondering what my plan of attack should be? I was thinking of changing the oil and trying that. Then disconnect the cylinders from the leg and seeing if I can get them to move without the weight of the leg.

Any suggestions would be greatly appreciated, thx.

 

[ziggy]

Re: I/O Leg won't go all the way down.

try standing on it. down pressure is much less than up pressure.

does the elec. motor run in the down direction?
is the trim pump reservoir full when in the down position. if it's full when it's in the up position. it would be overfull.

some of the items for not going down referenced in the service manual are.

air in the sytem
internal cyl.(s) leak
internal resistance in cyl.
hoses reversed on one cyl. only

drive housing interference with gimbal ring

get yourself service manual #3 (engine) and 4(drive). you'll be doing yourself a favor. they'll be the best tool in your toolbox.

 

[Smiks]

Re: I/O Leg won't go all the way down.

I have tried standing on it and it very slowly keeps going down (about 1 inch every 20 secs)

The pump does run when going down, but seems to hit that certain point, then whines likes it's full bottom (or full up) and stops.

I haven't been able to get it trim'd right down to check the reservoir when it's down.

Where can I look at either finding or picking those manuals up?

 

[ziggy]

Re: I/O Leg won't go all the way down.

ya could check the reservoir for fluid with the rams extended. the reservoir should be near empty as all the fluid would be in the rams.

ya could break the trim hoses free from the rams. it has to go down then unless there's something mechanical or internal ram failure that's preventing it.

as for the manuals.. wish i had better news for ya. but mercruiser has them. they show up on ebay. google mercruiser service manual #3 or 4. there are some places that sell them..... fwiw, i got my #1 and #2 off ebay. but i had to watch for them to show up.

 

[Alumarine]

Re: I/O Leg won't go all the way down.

I just went through this.

In my case I disconnected one end of the rams and found one went all the way in and one didn't.

I rebuilt the lazy one and it works fine now.

 

[Smiks]

Re: I/O Leg won't go all the way down.

Well I decided to check levels so I disconnected the cylinders from the leg and then extended them. Checked fluid levels and were good. Then decided to change the oil so bleed out the cylinders. Port side was a little stiff, but worked it for a bit and it freed up. Reconnected everything and worked the air, but still won't go down. Any more ideas?

 

[achris]

Re: I/O Leg won't go all the way down.

Disconnect the rams at the aft end and make sure the leg is free to move through the full range of travel. With the rams disconnected, secure them so they are sticking straight out. Have someone else operate the trim buttons and operate it DOWN. If one ram retracts fully, then the other one needs stripping and the end cap needs replacing.... If neither move, they both need their end caps replaced (or cleaned out and new seals put in).

Chris.......

 

[Smiks]

Re: I/O Leg won't go all the way down.

I got it all worked out. It was all the bad hydraulic oil inside. I pulled the cylinders apart, changed the o-rings and cleaned them up. Trim works like a charm now ^_^

Took the boat out for a burn on the lake.... started getting warm, so I shut it off. Let it cool for a while, got it back to shore, pulled the drive off to find a bit of water in there. U-joints are all right, impeller is hooped. The rustic bearing (I think that's what it's called, goes around the drive shaft is good still. So I'm pulling the drive apart and checking all the seals, bearings and gaskets while I'm at it.

I will keep you guys posted.

 

[achris]

Re: I/O Leg won't go all the way down.

.... The rustic bearing* (I think that's what it's called, goes around the drive shaft* is good still. .....

'Gimbal bearing' and 'yoke'.....