impellor on blueband merc 50 cant split lower unit

Dino89 · 26 March 2006, 20:14

hi
helping brotherinlaw with old blue band 50 merc got all the bolts undone and the lower unit drops slightly but cant get apart is there anything up top that has to be released because it feels like its a postive stop not like its just stuck on crud build up ,or is it just a bit of gentle persuasion thats required.
the impellor is shagged so need to change it ,thought i saw a strip down guide on here last year with photos of merc ,but cant find it now any advice appreciated
thanx

Nos4r2 · 26 March 2006, 20:29

Nothing up top has to be released on the 50 bluebands. Has he remembered to undo the bolt under the trim tab anode?

Assuming he has then just wiggle it a lot and eventually it'll drop off.

Richard B · 26 March 2006, 21:21

Quote:

Originally Posted by Dino89

thought i saw a strip down guide on here last year with photos of merc ,but cant find it now any advice appreciated
thanx

I did this thread on my Yamaha Impeller change if this helps: http://www.rib.net/forum/showthread.php?t=5840

jwalker · 26 March 2006, 21:32

Quote:

Originally Posted by Dino89

hi
helping brotherinlaw with old blue band 50 merc got all the bolts undone and the lower unit drops slightly but cant get apart is there anything up top that has to be released because it feels like its a postive stop not like its just stuck

Did you disconnect the gearshift?

Nos4r2 · 26 March 2006, 21:44

Quote:

Originally Posted by jwalker

Did you disconnect the gearshift?

You don't have to disconnect the gearshift on these motors it's a splined shaft that seperates when the leg drops.

jwalker · 26 March 2006, 21:47

OK, how does that work? It must rotate to change gear, I guess.

Dino89 · 27 March 2006, 08:18

thanks for replies , will be looking again at weekend beleive all bolts have been removed so will double check! then try a bit of persausion
will post what occurs!!

Nos4r2 · 27 March 2006, 20:43

Quote:

Originally Posted by jwalker

OK, how does that work? It must rotate to change gear, I guess.

Yeah, nice and simple. Can be a bit of a bugger to line back up though.

gavin · 28 March 2006, 19:08

Jwalker is right the gear shift, is not the rotational drive splined shaft, its the gearcase drive, when the casing splits slightly, look in and open the screw coupling holding the gearshift, up and down rod together the coupling needs to be opened to let the unit drop off, watch for the seal and spacer on the top of the shaft as the unit comes away, they often fall off when dissambelling

Nos4r2 · 28 March 2006, 19:42

Quote:

Originally Posted by gavin

Jwalker is right the gear shift, is not the rotational drive splined shaft, its the gearcase drive, when the casing splits slightly, look in and open the screw coupling holding the gearshift, up and down rod together the coupling needs to be opened to let the unit drop off, watch for the seal and spacer on the top of the shaft as the unit comes away, they often fall off when dissambelling

No, he's not. There is NO SCREW COUPLING ON THESE ENGINES. I OWN 2 OF THEM and have removed the lower units MANY TIMES.

This is what the lower unit looks like when it's off-the short splined shaft at the front of the unit is the gearchange shaft.

stu1288 · 28 March 2006, 20:50

Quote:

Originally Posted by Nos4r2

No, he's not. There is NO SCREW COUPLING ON THESE ENGINES. I OWN 2 OF THEM and have removed the lower units MANY TIMES.

This is what the lower unit looks like when it's off-the short splined shaft at the front of the unit is the gearchange shaft.

thats fucking shagged

Nos4r2 · 28 March 2006, 21:15

yep.... It's from a scrapper I bought. I took the engine apart with a lump hammer

Surprisingly, the lower units internals were fine. That chunk missing from the skeg isn't broken off, it's corroded!

Downhilldai · 28 March 2006, 21:32

Quote:

Originally Posted by stu1288

thats fucking shagged

Good analysis.

You're probably qualified to post on this thread:
http://www.rib.net/forum/showthread.php?t=13679

Richard B · 29 March 2006, 05:42

Quote:

Originally Posted by gavin

Jwalker is right...

Quote:

Originally Posted by Nos4r2

No, he's not....

Its possible you're both right... production of same model, same year items can change for no apparent reason, usually change of supplier for a component. I blame supply chain management

Anyway, enough of that... disagreement and contradiction makes for more amusing reading!

jwalker · 29 March 2006, 10:01

Quote:

Originally Posted by Richard B

Its possible you're both right...

I didn't claim to be 'right'. I simply asked whether the gearshift had been disconnected.

Slaphead · 29 March 2006, 11:46

Not wanting to change the thread or anything, but does anyone have a prop for a 50 Merc blueband they would like to sell- 13 spline shaft, 4 cylinder,etc..

Dino89 · 29 March 2006, 17:31

nice sunny day thoght we would have another look at splitting lower unit two things first its a red band on the engingine cover and number on the engine plug is B17396.
right the lower unit drops about 10mm and stops on a positive knock which can be felt through the fly wheel on top , it seems by feel that what ever is stopping it splitting is directly under the fly wheel
any ideas ?? if theres anything under there that could stop it part ie circlip ?or nut ?
Dino

Dino89 · 30 March 2006, 14:30

refer to my last post first as more info in that ,another thought is does anything have to line up to allow it to drop ? is there a difference between the red banded and blue banded mercs as the way it drops to a 10mmm gap seems to positive to be crud gave it a good go with wedges but will not move anymore can post photos if any use .

Paul F · 30 March 2006, 16:11

If it hasnt been removed for some time,it may be corroded in the drive shaft to crank splines or if it has the same arrangement for the gear select lower down it could be there. I will delve into some old books tomorrow
Paul

Nos4r2 · 30 March 2006, 16:27

It SHOULD be the same lower unit-to the best of my knowledge it's the same lower unit from 1968ish to 1985ish....but your engine is listed as being 1964-1966 and at a guess I'd say probably 1964 as it's towards the beginning of the numbers listed. You need to check spline size on the prop output shaft to be sure which model, but my manual which covers 63-88 still doesn't show a bolt.

Have a look at http://www.oldmercs.com for parts lists etc

This is unless yours is the one-piece cowl much later model with a red band that would probably make it less than 10 years old....