Changing the impellor on a Merc 3.5 4St any tips?

[Ripster]

About to service the water pump on a 4st 3.5hp mariner/merc 2010 model OB and have not done it before. It looks a very straight forward job, but any tips (that might not be obvious to first timer) would be welcome..


For example, the position of the gear shift lever during the process - neutral or engaged? Any others?

 

[lynall]

Good site http://forums.iboats.com/forum.php


Lynall

 

[VicS]

Another good forum for advice is http://www.marineengine.com/boat-forum/forum.php

Id think the gear position will be determined by the position it needs to be in to access the clamp between the two halves of the shift rod.

The leg looks exactly the same as the two strokes. no hidden snags as far as I know.

Lightly grease all the bolt threads when you reassemble it. Also the spline on the vertical drive shaft.

 

[jwilson]

Another good forum for advice is http://www.marineengine.com/boat-forum/forum.php

Id think the gear position will be determined by the position it needs to be in to access the clamp between the two halves of the shift rod.

The leg looks exactly the same as the two strokes. no hidden snags as far as I know.

Lightly grease all the bolt threads when you reassemble it. Also the spline on the vertical drive shaft.

If it's the same as the two-stroke 3.5 getting the shift rod and water tube lined up again and fastened through the little rubber-plug hole is a bitch.....

 

[Ripster]

Thanks for all the replies. Got it all out - no dramas and all ready to go back in. I can already see that lining up all the tubes and shafts is going to be a cow!

I have drained the gearbox as well and no milk all nice clean oil - does anyone know the viscosity of the gear oil??? Its not in the manual afaik. I have got 75, 80, 90 but dont know which it is.

 

[VicS]

Thanks for all the replies. Got it all out - no dramas and all ready to go back in. I can already see that lining up all the tubes and shafts is going to be a cow!

I have drained the gearbox as well and no milk all nice clean oil - does anyone know the viscosity of the gear oil??? Its not in the manual afaik. I have got 75, 80, 90 but dont know which it is.

Outboard gear oil is usually around EP80 or EP90 ( OMC electric shifts and Seagulls being the most notable exceptions)

Outboard engine gear oil differs from automotive gear oil in having additional inhibitors and a emulsifiers to counter the effects of any water ingress... or so they tell us.

Note that when you fill an outboard gear box you do so via the bottom hole untill it flows from the top hole. This ensures that the box is correctly filled with no trapped air and is why outboard gear oil is supplied in squeezable tubes with a nozzle that will "screw" into the hole.

Ideally you should fit new seals to the drain and level plugs.


PS. I use automotive EP90 oil and am still using the original (1984) washers on the drain/level plugs

 

[Ripster]

Outboard gear oil is usually around EP80 or EP90 ( OMC electric shifts and Seagulls being the most notable exceptions)

Outboard engine gear oil differs from automotive gear oil in having additional inhibitors and a emulsifiers to counter the effects of any water ingress... or so they tell us.

Note that when you fill an outboard gear box you do so via the bottom hole untill it flows from the top hole. This ensures that the box is correctly filled with no trapped air and is why outboard gear oil is supplied in squeezable tubes with a nozzle that will "screw" into the hole.

Ideally you should fit new seals to the drain and level plugs.


PS. I use automotive EP90 oil and am still using the original (1984) washers on the drain/level plugs

Thanks Vic, I change will this annually anyway and like you I am going to use the std automotive stuff. Noted on the filling method - thanks. New sealing washers all round as well.