MD2B MS Gearbox

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North Tipp

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I've got a Volvo Penta MB2B in a 1982 Myra 21, with an MS gearbox. The problem is that the water jacket in the reducer gearbox is cracked (seriously cold winter in Ireland this year, -13c in jan). My question is, why is the reducer box water cooled at all. With a 25hp engine, only capable of 6knots surely the gearbox will not over heat.
Is it possible to bypass the gearbox with the seawater pipe thereby going straight to the impeller. Can the gearbox over heat?
It looks like a big job to take off the reducer and weld or replace it.
Any help greatly appreciated.
 
North Tipp said:
I've got a Volvo Penta MB2B in a 1982 Myra 21, with an MS gearbox. The problem is that the water jacket in the reducer gearbox is cracked (seriously cold winter in Ireland this year, -13c in jan). My question is, why is the reducer box water cooled at all. With a 25hp engine, only capable of 6knots surely the gearbox will not over heat.
Is it possible to bypass the gearbox with the seawater pipe thereby going straight to the impeller. Can the gearbox over heat?
It looks like a big job to take off the reducer and weld or replace it.
Any help greatly appreciated.
Click to expand...
Go here http://www.marinepartseurope.com/en/volvo-penta-explodedview-7746410-44-212.aspx spares and INDICATION of prices. I suppose you could suck it and see, put blanking plates on the water in and out on the box and join the raw water pipe.
Stu
 
skipper_stu said:
Go here http://www.marinepartseurope.com/en/volvo-penta-explodedview-7746410-44-212.aspx spares and INDICATION of prices. I suppose you could suck it and see, put blanking plates on the water in and out on the box and join the raw water pipe.
Stu
Click to expand...

Thanks Stu.
A couple of people have suggested to me that cooling of that gearbox is unnecessary, and that I could by pass it. I suppose I could run it, by passed, and keep an eye on the temperature of the gearbox housing.
 
Other gearboxes they fitted before (?) the MS boxes were not water cooled.

I'd give it a cautious try without the water cooling.
 
ms red housing crack

The red gear housing has always been prone to frost cracking when not drained over winter
or filled with antifreeze
The housing is machined to take a large 4" plus roller bearing and is thus liable to leak oil at the crack.
Running without water may be ok but the housing will still be weakened

The other problem is that the reduction gear runs on a stub inside the same casing and takes all the reverse thrust and suffers with rope round the prop shaft /coupling rubbers shearing etc
 
North Tipp said:
I've got a Volvo Penta MB2B in a 1982 Myra 21, with an MS gearbox. The problem is that the water jacket in the reducer gearbox is cracked (seriously cold winter in Ireland this year, -13c in jan). My question is, why is the reducer box water cooled at all. With a 25hp engine, only capable of 6knots surely the gearbox will not over heat.
Is it possible to bypass the gearbox with the seawater pipe thereby going straight to the impeller. Can the gearbox over heat?
It looks like a big job to take off the reducer and weld or replace it.
Any help greatly appreciated.
Click to expand...


I would just take the sea suction straight to the sea inlet and seal of the cooling passages and see how it goes. My feeling is that in the UK it is usually so cold it may not be a problem

I would certainly not shell out many hundreds of pounds on a new gearbox even if you could find one until proving it won t keep cool.

Just feel it from time to time and see how hot it gets. You have such a wee dinky boat for this engine the gearbox and thrust is hardly loaded...Let us know how you get on after a few tests.
 
ive got a md3 and i by-passed the gearbox about 18 months ago and shes still going. i wouldnt think for the age of the motor it would be worth the money to fix it, the longest ive run the motor continiously is for about 2.5hrs at 1800-2000 revs and no problems although this year as soon as the mechanic is avalible im putting a new motor in
 
Thanks for the help folks. I'll give it a lash, and ultimately, keep an eye open for a new engine. It'd be a pity to part with the original Penta, so I hope she keeps her cool.
 
If it is just a crack in the housing then it should be possible just to patch it up with a sealant and then continue to run as it is
 
Hey, I have exact same issue mb2b og broken cooling on the ms gear. I have often wondered if the cooling was needed before it cracked.
So how did it go? Was there any problems bypassing the gearbox?

Best regards
Miguel
 
North Tipp said:
I've got a Volvo Penta MB2B in a 1982 Myra 21, with an MS gearbox. The problem is that the water jacket in the reducer gearbox is cracked (seriously cold winter in Ireland this year, -13c in jan). My question is, why is the reducer box water cooled at all. With a 25hp engine, only capable of 6knots surely the gearbox will not over heat.
Is it possible to bypass the gearbox with the seawater pipe thereby going straight to the impeller. Can the gearbox over heat?
It looks like a big job to take off the reducer and weld or replace it.
Any help greatly appreciated.
Click to expand...
 
The cooling is mainly in the region of the thrust bearing. Some have bypassed the gearbox cooling and had no problems and some have found the gear box warms up. Why not try it and see what happens. I believe one poster actually fitted an exterior cooling pipe.

This is the reason people flush the SW cooling system with antifeeze as part of winterizing. as water often lies in this passageway.
 
Thanks.. :) mine broke because the buttom nut was tighten too hard and it crack the casing.. I am running some tests now there i am monitoring the temperature while the engine is running and in gear, until now the temperature has reacht 60 C.
 
Sorry to resurrect this thread :) but I have the same issue - creamy oil in my MS2 gearbox... I've a Volvo Penta MD2010 - so only 10hp... I'm keen to hear from @Antoniopedersen @whatif & @North Tipp if bypassing the oil cooler caused any issues of overheating etc & if they would recommend it?

Anyone else have any experience of this? Cheers, Ricky
 
It is a different gear box but it should be fine. The OP's Gearbox had cored passage ways in the gearbox casting which remain filled with water so require to be filled with antifreeze if a chance of cold weather ashore. I deal with this by flushing through with an antifreeze mixture which protects the gearbox, engine and water trap. Your gearbox appears to have components that can be replaced. Why don t you try bypassing and see if it runs warm when there is no cooling water. I doubt you will have a problem but if you do then just deploy the fishing lines and return at trolling speed.
 
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