Mariner 30hp - lost all power at prop!

whisper · 29 June 2009, 21:18

Hi, I have a Mariner 30hp 2 stroke (around early 90s) which was going fine until I was going along at ¾ revs then it lost propulsion, it was like as if it was in neutral but the engine was still revving but without any load. The prop is new and the shaft that the prop bolts to does not turn either. It’s like it just popped out of gear!

Does any one know what could be wrong?

Poly · 29 June 2009, 21:36

Quote:

Originally Posted by whisper

It’s like it just popped out of gear!

someone more knowledgeable may be able to shed some light - but from your description it could be that the rods/cables that connect the gear lever to the gearbox have become disconnected.

whisper · 29 June 2009, 21:54

I’ve had a good look and the gear leaver on the side of the engine still moves backwards and forwards ok but it’s not going into gear.

Poly · 29 June 2009, 21:59

Quote:

Originally Posted by whisper

I’ve had a good look and the gear leaver on the side of the engine still moves backwards and forwards ok but it’s not going into gear.

there are a series of levers/rods that transfer the movement from the side of the engine, down the inside of the leg to the gearbox.

sam12345 · 29 June 2009, 22:00

We had the shift rod on a mariner 75 snap in the gear box casing below the seal.
If everythings alright and moving okay under the cowling, then you can work your way down the changer rod to under the powerhead by the transom. If this moves as well then your problem is in the actual gearbox itself.

whisper · 29 June 2009, 22:13

Quote:

Originally Posted by sam12345

work your way down the changer rod to under the powerhead by the transom.

How do I check this?

Downhilldai · 29 June 2009, 22:58

Have you also lost reverse gear?

As others have said, it sounds like the gearshift mechanism has disconnected or broken, somewhere. I'm not sure of the detail on this actual motor, but there will be a connection point in the gearchange rod somewhere in the leg, which allows the lower unit to be removed. This may be the cause of your problem. The connection can be a clevis pin, threaded rod or clamp. Have a poke around and you'll find it somewhere between the tray below the powerhead and the lower unit.

Bigmuz7 · 29 June 2009, 23:00

Underneath the powerhead .. the main shaft goes down into the gearbox through the leg .. it is splined where it receives into the powerhead, sounds like its sheared there and you have no gears what so ever , usually just below the splines, below the power head..unless ... do you still have reverse ?

Bigmuz7 · 29 June 2009, 23:07

Feck I'm a slow typer

uncle al · 30 June 2009, 07:22

ring me at work if you want to 01869 326411 have your serial number ready

jwalker · 30 June 2009, 11:32

For checking the gear change rods. On this engine, part way down the leg you will find a longish hexagonal nut which connects the gearbox gear change rod to the engine lever rod. The long nut is locked with thin nuts. Move the engine lever to check that the rods are properly connected together. If the rods are connected and move up and down when the engine lever is moved, it would appear that you have a failure in the lower unit or the engine drive shaft.

whisper · 30 June 2009, 14:10

Sorry I forgot to say that there is no reverse gear either.

Spoken to Uncle Al and read all your posts and started to strip it down, disconnected the gear change rod at the joint at the back of the leg and moved the shift shaft up and down but prop still won’t engage.

The next thing I would guess is to drop the gear box and check the drive shaft?

uncle al · 30 June 2009, 19:33

i meant to tell you this morning drain the gear oil and look for metal particalls/filings if the oil comes out with lumps of metal game over.

Bigmuz7 · 01 July 2009, 07:28

Quote:

Originally Posted by whisper

check the drive shaft?

and if it is the shaft .. the fun has yet to begin getting the snapped off bit out of the crank .. keep us posted

whisper · 01 July 2009, 13:02

Drained the oil and there was a few bits but my farther thinks that this would be normal???

Removed the gearbox and the drive shaft is ok, so it looks like the fault is in the gear housing?

Downhilldai · 01 July 2009, 17:49

The gear oil shouldn't contain any 'bits'.

You could pull the propeller shaft hub out to see what's been going on in there.

Then buy a good second hand lower unit, 'cos it will probably cost more than that to fix the original if 'bits' came out with the oil.

Bigmuz7 · 01 July 2009, 20:14

Quote:

Originally Posted by Downhilldai

The gear oil shouldn't contain any 'bits'.

Depends how large they are.. because I have to say that in all my experience of draining hubs and gearboxes, its true to say I have seen more metallic oil contamination from outboard legs, which people suggest is normal which to me doesnt look like it should be. Perhaps its down to the metals used in the gears, but in any other environment if I see flakes, or grey or silvery oil, its a portent of something to come, and yet, the legs that I've seen it in, have run on and on

Obviously the situation here as outlined by the OP is different, as there is a failure involved, and I suspect that people with outboards in general do not change their gearbox oil often enough, because its a smelly dirty job, but by jingo its an important one, and not least of all because its submerged so much ,.. its an annual job IMO

whisper · 02 July 2009, 19:42

Don’t worry about the bits, my father drained the gear box and we strained the oil through a cloth and the bits were nothing at all.

I have had a look again tonight and I think that it’s going into forward and reverse gears ok because I can feel the shift rod indexing the gears and I can hear the gears inside turning.

If I turn the drive shaft I can feel it sort of click into place at the same point in every revolution, so……

Could the drive shaft be snapped inside the gear box? Also how do I get it out?

Bigmuz7 · 02 July 2009, 20:15

Read JW's post again then,.. perhaps he's onto something but not just quite what you see ?

could there be a shifter problem with the rods ?

whisper · 04 July 2009, 08:59

I think it’s going into gear fine and since draining the oil I can hear the gears turning so I think the shaft is snapped inside the gearbox. I can’t strip it down any further without specialist tools so as Downhilldai said the best thing is to replace the gearbox. I have found a brand new one on ebay for £299 ouch! But probably worth it?