Raw water leak from the rear of the Combi

[marco]

Hello Fellow Vega sailors,

After more than 320 hours of engine use during my tour from Holland to Venice by sea, my Vega engine (MD7A with original Combi system) has developed a small leak of raw water mixed with emulsionated grease from the rear of the Combi, where the prop shaft enters the reduction box (the back of the engine).
The rear bearing of the prop shaft, the one close to the prop, is worn out and the shaft is abit loose, this could explain worn seals in the reduction box, but I would expect engine oil to come out, not salty water.
The engine oil is not emulsionated.

Any suggestion to explain this phenomenon?

I have roughly another 50 hours by engine to reach Venice. I plan to go ahead as no spare parts and expert mechanic to solve the problem. Your opinion?

Thanks for the advice!
marco baldan
Albin Vega 3339 Spray

 

[winslowbuoy]

Hi Marco - I think sea water enters the prop mechanism and then creeps up the gap between the outer control tube and the inner prop[ shaft. the water seems to go up to the combi gear box the emulsifys the grease in there and comes out of the oil seal at the back of the combi mechanism.

Not sure how to cure it though; I finally got fed up with the mess and changed to a Beta engine with a coventional prop and gear box.

Mike
________________________________
From: Marco africanmarco@...
To: AlbinVega@yahoogroups.com
Sent: Wednesday, 15 August 2012, 9:44
Subject: [AlbinVega] Raw water leak from the rear of the Combi

Hello Fellow Vega sailors,

After more than 320 hours of engine use during my tour from Holland to Venice by sea, my Vega engine (MD7A with original Combi system) has developed a small leak of raw water mixed with emulsionated grease from the rear of the Combi, where the prop shaft enters the reduction box (the back of the engine).
The rear bearing of the prop shaft, the one close to the prop, is worn out and the shaft is abit loose, this could explain worn seals in the reduction box, but I would expect engine oil to come out, not salty water.
The engine oil is not emulsionated.

Any suggestion to explain this phenomenon?

I have roughly another 50 hours by engine to reach Venice. I plan to go ahead as no spare parts and expert mechanic to solve the problem. Your opinion?

Thanks for the advice!
marco baldan
Albin Vega 3339 Spray

 

[maarten_vanemmerik]

Marco,



Here is my best guess and resolution:



There is an inner drive shaft which powers the propeller and an outer shaft
linked to the control tube, which controls the pitch of the propeller. The
run with the same speed but the outer shaft can slide a few cm over the
inner shaft if you move the lever. The drive shaft is below the water line
and water can flow between the inner and outer shaft. The water comes in at
the propeller side and comes out in the combi box, where the outer shaft
ends.



Normally there should be grease between the inner and outer shaft, or at
least on the prop side, preventing water to come in. The grease is provided
by removing a small bolt on the propeller and attaching a grease gun. You
should inject the grease until you see it coming out near the propeller
blades. This means that the inside of the prop is full and no water can
travel up the shaft. You may be able to do the greasing when the boat is in
the water.



Maarten



From: AlbinVega@yahoogroups.com [mailto:AlbinVega@yahoogroups.com] On Behalf
Of Marco
Sent: woensdag 15 augustus 2012 10:44
To: AlbinVega@yahoogroups.com
Subject: [AlbinVega] Raw water leak from the rear of the Combi





Hello Fellow Vega sailors,

After more than 320 hours of engine use during my tour from Holland to
Venice by sea, my Vega engine (MD7A with original Combi system) has
developed a small leak of raw water mixed with emulsionated grease from the
rear of the Combi, where the prop shaft enters the reduction box (the back
of the engine).
The rear bearing of the prop shaft, the one close to the prop, is worn out
and the shaft is abit loose, this could explain worn seals in the reduction
box, but I would expect engine oil to come out, not salty water.
The engine oil is not emulsionated.

Any suggestion to explain this phenomenon?

I have roughly another 50 hours by engine to reach Venice. I plan to go
ahead as no spare parts and expert mechanic to solve the problem. Your
opinion?

Thanks for the advice!
marco baldan
Albin Vega 3339 Spray

 

[africanmarco]

Thanks Marteen,

Clear and sound! Will try to grease in the water. Apart from this small problem and the worn out rear bearing, the engine runs smoothly and regularly!

Fair winds,
marco

Inviato da iPad

Il giorno 15/ago/2012, alle ore 17:26, "Maarten van Emmerik" mve@... ha scritto:

 

[africanmarco]

Thanks Lueder!

Inviato da iPad

Il giorno 16/ago/2012, alle ore 20:06, "wso_ornbau" lueder.heidemann@... ha scritto: