Stuck drive shaft on O/B

[Paddys milestone]

I have an oldish Mariner 50 2 stroke outboard which still runs well, however the water pump impeller needs renewal.
I have removed all the nuts and bolts holding the lower assembly (gearbox?)to the main body and as per various advice on youtube, tried to pull the whole thing apart.

I can get it to split apart for about 8 mm or so ,but it sticks pretty solid at this point, wont go any further. I have tried levering it gently and evenly but no luck.

Apparently the main driveshaft has a spline which ges into (presumably) the end of the crankshaft, As far as I can tell, this should be the only reason for it sticking.

I would be grateful for any suggestions on what to do next, Any ideas?

 

[rotrax]

Without teaching my granny, etc, can you confirm you have disconnected or slackened the clamp for the gearchange rod?

 

[Paddys milestone]

Thanks for your reply, I don't see where this clamp might be,it is not obvious just by looking at the motor.
Looking at some of the vids on utube there seemed to be a clamp located on the outside of the housing but it is not obvious on this particular motor. So the answer to your question is no. However it would seem to be a very good idea to go back and have another look. I really don't want to use brute force to separate the two castings so will tread gently.
Thanks again.

 

[Rolling Stone]

There is usually another bolt hidden under the anode/trim tab. Gear shift and drive shaft are splined. Once you have parted an inch or two there may be a pipe for speedo feed which simply pulls apart.

 

[VicS]

Thanks for your reply, I don't see where this clamp might be,it is not obvious just by looking at the motor.
Looking at some of the vids on utube there seemed to be a clamp located on the outside of the housing but it is not obvious on this particular motor. So the answer to your question is no. However it would seem to be a very good idea to go back and have another look. I really don't want to use brute force to separate the two castings so will tread gently.
Thanks again.

My first thoughts on reading your question were that the drive shaft is rusted in to the crankshaft but without knowing the exact engine identity I cannot say whether or not you would get an 8mm separation of the gearcase from the driveshaft housing ,

However if you have not disconnected the gear shift rod that is most likely your problem as Rotrax suggests.

Can you post the Serial number. Not promising but armed with that info it may be possible to suggest where to disconnect the gear shift

If you cannot get any help through this forum post your question on the Mercury/ Mariner board of the iBoats forums and/or the MarineEngine forums but post the full model details including the serial number.

Mercury & Mariner Outboards

https://www.marineengine.com/boat-forum/forums/mercury-mariner-outboard-forum.30/

.

 

[Paddys milestone]

Thanks Vic... The number is 74211.
Unfortunately I am away from base this week and won't be back until the middle of next. I will have another look for the gear linkage then, try & post a pic or 2 and report back.
Muchos Gracias

 

[VicS]

Thanks Vic... The number is 74211.
Unfortunately I am away from base this week and won't be back until the middle of next. I will have another look for the gear linkage then, try & post a pic or 2 and report back.
Muchos Gracias

Sorry. I cannot get anything from that number. I was expecting 7 or 8 digits, possibly alpha-numeric

 

[Paddys milestone]

Sorry. I cannot get anything from that number. I was expecting 7 or 8 digits, possibly alpha-numeric

OK. Vic. I will have another look and see if I can get the correct number. It will be friday at the earliest before I am back.

 

[Paddys milestone]

Just been back to have another look at the O/B.

There is a rod which runs vertically from the gear selector lever at the front of the engine.
It runs down through the main motor pivot and can just be seen where it enters the bottom section of the unit..presumably this is where it goes into the gearbox.
As I operate the gears(forward-neutral- reverse) the rod can be seen to turn accordingly,and as I try to separate the two parts, I can see it moving linearly a small amount.
Presumably it will be connected to the gearbox, possibly by a spline or a square socket.
There is however no place on the assembly where the rod can be freed ,except at the actuating arm,where it is connected by a roll pin,which is extremely difficult to access and in any case only goes halfway into the boss of the arm ,making it impossible to punch out.
Surely there must be a simple way to access the water pump impeller without resorting to brute force to get at it?