Something went bang??

Waterman · 12 April 2010, 10:15

While out on the water last week the starboard engine suddenly over revved so I shut it down. I thought it might have been the rubber hub on the prop that was slipping so came home on one engine. When I dropped the lower leg there was something extra attached to the drive shaft

.. Anybody tell me what Ive broken?? Engine is a 2000 mariner 2 stroke (2 cylinder) model.
The piece in the pics is what i pulled off the top of the drive shaft. It came off fairly easily but the cam shaft end looks to broken/snapped??

ashbypower · 12 April 2010, 11:00

Is it an Ex RNLI Engine??

Waterman · 12 April 2010, 12:16

Possibly??

What difference would this make??

doggypaddle · 12 April 2010, 12:51

It just looks like a shaft extension piece. could be genuine part or a piece from one of the "shaft extension kits" you can buy for most engines.
Is the leg one piece or is there an extra bolt on piece the same length as the extension that shaft provides?
I am sure someone who knows the particular engine better than me can tell you if its a genuine factory part or a piece from a kit.
Your next problem is getting the broken stub out of the crankshaft end, it may well be very tight due to it being twisted, you will probably need to drop the powerhead off to gain access, and maybe drill it right through and tap it, so you can either wind a bolt through to jack it out, or attach a slide hammer. if you're very lucky there may be enough poking out to grab it with a pliers.
the next question is why did it break. is the gearbox free to turn did you hit something? any damage visible on the prop?

Nasher · 12 April 2010, 13:19

Doggy-P beat me to it.

It does look like a shaft extension, and the rest must be stuck in the end of the crankshaft.

Nasher.

Waterman · 12 April 2010, 14:07

Cheers guys,

Have no idea how it happened?? Didint hit anything but was at WOT when it failed.

Any idea how one would go about identifying what driveshaft extension kit would be a replacement one??

uncle al · 12 April 2010, 15:22

hi your obm is an ex R.N.L.I. obm and the part number is RDG3952 which can be ordered from any Merc/Mar dealer my phone number is 01869 326411 during office hours only

doggypaddle · 12 April 2010, 16:38

Quote:

Originally Posted by uncle al

hi your obm is an ex R.N.L.I. obm and the part number is RDG3952 which can be ordered from any Merc/Mar dealer my phone number is 01869 326411 during office hours only

Fantastic service from uncle al again, bet he cant get the broken piece out as easily as giving you the part number though

Nos4r2 · 12 April 2010, 17:16

Quote:

Originally Posted by doggypaddle

Fantastic service from uncle al again, bet he cant get the broken piece out as easily as giving you the part number though

Hopefully the splines aren't as twisted at the end of the crankshaft of it may be an engineering shop job to remove it.

You'll want to investigate the gearbox too-it's taken a lot of force to do that damage!

Bigmuz7 · 12 April 2010, 18:25

Another vote for twins then

Poly · 12 April 2010, 23:17

Quote:

Originally Posted by Bigmuz7

Another vote for twins then

Nah - if only had the port engine he wouldn't be facing a very expensive repair

doggypaddle · 13 April 2010, 07:52

Quote:

Originally Posted by Polwart

Nah - if only had the port engine he wouldn't be facing a very expensive repair

MarkM · 13 April 2010, 08:53

Saw something like it before.

doggypaddle · 13 April 2010, 14:49

i have plenty of landrover halfshafts like that.

Waterman · 26 April 2010, 22:42

Finally got around to taking the powerhead off this evening. The end of the extension shaft is just visible in the crank shaft. Any suggestions on how to remove it?? I was thinking of drilling and tapping the centre of the extension shaft and trying to pull it out but from the photo of the full extension shaft it looks like it has a thread at the top??

ollyit · 26 April 2010, 22:57

what a horrible job, best of luck

Nos4r2 · 26 April 2010, 23:21

Quote:

Originally Posted by Waterman

from the photo of the full extension shaft it looks like it has a thread at the top??

No, no thread at top.That's not a pic of your extension shaft. You may even manage to pull it out by aralditing something to it. Nothing to lose by trying it...

m chappelow · 26 April 2010, 23:41

if gluing something to it wont budge it you could try and carefully spot weld a piece of long rod/bar to it and even make a makeshift slide hammer ,
,,if you have accesss to a decent drill and tap/dye set could you not tap the broken shaft and run a bolt through a plate washer and wind its self out perhaps ,,

Nos4r2 · 26 April 2010, 23:57

Quote:

Originally Posted by m chappelow

,,if you have accesss to a decent drill and tap/dye set could you not tap the broken shaft and run a bolt through a plate washer and wind its self out perhaps ,,

I reckon if glue doesn't work (it's not really likely to, but it'll do no harm if it doesn't and it's easy to try) then drilling/tapping it is probably the answer. It's a bit close to oil seals to be welding in there and one small bit of spatter could lock it in permanently.

Bigmuz7 · 27 April 2010, 07:45

Quote:

Originally Posted by Nos4r2

It's a bit close to oil seals to be welding in there and one small bit of spatter could lock it in permanently.

Indeed, but worse .. I have seen some people put the earth strap on the other side of a bearing in this situation

.. a small flash later as they strike the arc, and they've ended up welding the bearing solid , destroying it because of an arc jumping through the bearing to get to the electrode on the shaft

(hope that makes sense)

There looks to be enough length on the crank to attach to for welding,.. but I agree, I'd prefer a drill and tap myself,

as long as the shaft hasnt been case hardened.