Water in the oil

[MiPra]

Hi to all MB2A50S users. I'm a happy user of this very nice engine. I have had only small problems in my 2 years of usage. This year I discovered some water in the oil (engine oil) and at first I thought it was about the seal between the engine block and head. The power of the engine wasn't changed only oil structure was changed to a light brown color. I immediately stopped using the engine. As the first step I replaced the oil (yacht was laying on the lake) but without using the engine I have back water in the oil. I think it must be different seal between the engine shaft and the leg. Does anyone from you have experience with parts I have to replace? Appreciate your help. Later I can attach some pictures with the engine and oil structure.

[Sarabande]

[quote='MiPra' pid='246' dateline='1256133302']
Hi to all MB2A50S users. I'm a happy user of this very nice engine. I have had only small problems in my 2 years of usage. This year I discovered some water in the oil (engine oil) and at first I thought it was about the seal between the engine block and head. The power of the engine wasn't changed only oil structure was changed to a light brown color. I immediately stopped using the engine. As the first step I replaced the oil (yacht was laying on the lake) but without using the engine I have back water in the oil. I think it must be different seal between the engine shaft and the leg. Does anyone from you have experience with parts I have to replace? Appreciate your help. Later I can attach some pictures with the engine and oil structure.
[/quot


It is possible that the Oil filler cover gasket has failed at the point were the water return pipe is fitted.
Personally I think this is a poor design and converted mine so that the water exits through a pipe push fitted into the block then into the spigot that connects the outlet pipe. Worked for me anyway!

[MiPra]

Dear Sarabande,
I have never "opened" this engine so I looked at the workshop manual and by your description find out that you are talking about item 11 from page 22. Am I right? For this I have to dissmount leg first and than dissasembly the engine as I can see on page 22. Agree? Can you more closely describe your conversion or add some pictures of that?

[Sarabande]

(30-10-2009 10:13 AM)MiPra Wrote:  Dear Sarabande,
I have never "opened" this engine so I looked at the workshop manual and by your description find out that you are talking about item 11 from page 22. Am I right? For this I have to dissmount leg first and than dissasembly the engine as I can see on page 22. Agree? Can you more closely describe your conversion or add some pictures of that?

You can remove the cover in situ 4 bolts using 10mm socket but it is awkward and this would only enable you to check the condition of the gasket. Sorry have no photo as the conversion was done back in the spring and I do not need to remove it yet. All I have done is put a mechanical barrier (ie a tube) between the cover and the block.

As it does not take long to remove the engine and the water oil needs sorting, if you can take the engine to your workshop you will find that stripping the unit down is no big deal.

Best of luck

Sarabande

[MiPra]

Thank you Sarabande for your quick reply. Only to understand correctly what I have to check - look at the attached picture. Do you mean gasket item 11 from that picture? And what do you mean by situ? Maybe description from the same picture can help. As I'm not native speaker maybe I don't understand everything correctly. Sorry for that. Can you instead of photo make some comment from that picture or another pictures from Workshop manual? Appreciate your help.

[Sarabande]

(30-10-2009 05:00 PM)MiPra Wrote:  Thank you Sarabande for your quick reply. Only to understand correctly what I have to check - look at the attached picture. Do you mean gasket item 11 from that picture? And what do you mean by situ? Maybe description from the same picture can help. As I'm not native speaker maybe I don't understand everything correctly. Sorry for that. Can you instead of photo make some comment from that picture or another pictures from Workshop manual? Appreciate your help.

No, that is the intermediate gasket. It is item 12 I am referring you to look at, at the bottom L/H corner you can see the moulded tube projecting, turn it over and the inside edge has a cutaway channel that takes the sealing gasket and the only thing keeping the water from entering the sump is a "O" type seal which is moulded in the cover gasket. The gasket can be distorted I have been told and the O type ring would then allow water into the sump. Mine was flattened by an over enthusiastic mechanic with his spanner. I have also been told that the older engines had a aluminium cover but this was superseded by the plastic.

[Sarabande]

(30-10-2009 06:56 PM)Sarabande Wrote:  

(30-10-2009 05:00 PM)MiPra Wrote:  Thank you Sarabande for your quick reply. Only to understand correctly what I have to check - look at the attached picture. Do you mean gasket item 11 from that picture? And what do you mean by situ? Maybe description from the same picture can help. As I'm not native speaker maybe I don't understand everything correctly. Sorry for that. Can you instead of photo make some comment from that picture or another pictures from Workshop manual? Appreciate your help.

No, that is the intermediate gasket. It is item 12 I am referring you to look at, at the bottom L/H corner you can see the moulded tube projecting, turn it over and the inside edge has a cutaway channel that takes the sealing gasket and the only thing keeping the water from entering the sump is a "O" type seal which is moulded in the cover gasket. The gasket can be distorted I have been told and the O type ring would then allow water into the sump. Mine was flattened by an over enthusiastic mechanic with his spanner. I have also been told that the older engines had a aluminium cover but this was superseded by the plastic.

In situ....... Means with engine in place. Hope that is clear for you.

[MiPra]

Thank you, will look at item 12 closer. Hope will have time this weekend.

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Can you take out the engine from bed with leg on it and only propeller have to be taken out or leg must be splitted from the engine before lifting the engine? Maybe it will be simpler to do it at workshop.

[John Smith]

Hi MiPRA.
The only time that my engine had water in the oil was when the seal on the main shaft became worn.
This seal is between the lower leg and the main engine. It is normally below the waterline.
The symptoms were

Engine ran slowly. This is because of the extra pressure behind the pistons via the oilpan.
When the oil dipstick was removed, the oil gushed from the dipstick hole.
The oil emusified with the water, so forming a thick, white, sludge.

The only cure was to get the boat put ashore, remove the engine, then reolace the shaft seal.

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Sorry for the spelling.
The seal was replaced, not reolace.

[MiPra]

I just took out the engine. Had to split the leg before lifting the engine, because my boat has no room to do it without splitting the engine. Will keep you informed.

[Ciao Bye]

Item 12, the plastic filler and the gasket had been changed. The plastic filler was bend by the heat or fatigue I presume and was not sealing enough. Had no water in the oil but it was only a question of time.

Went to Honda and bought a new one. In think it was in metal now. I must have the part number somewhere. I think it cost around 25$ US.

John
Canada

[MiPra]

Dear all,
I'm just working back on the MB2A/50S overhauling and am attaching a few pictures how my MB2A50 looks disassembled. As I wrote I found water in the oil. Before getting the boat from the water I replaced the old oil which was mixed with the water. I was surprised that water is back after few days in the oil with no running engine. So I think it isn't because of the head gasket.
After disassembly you can see also the oil in the shift rod well.
In the bottles you can see how much water was in the oil.
On other pictures you can see the condition of my gaskets at oil pan.
As I see the gasket 11 from page 22 looks good.
O-ring 10 from page 22 is damaged and I didn’t recognize its function.
I took out also sealing ring 7; page 22 and I think it should be replaced. I think this is the main reason of the failure.

What other gaskets and O-rings do you think I should replace within this overhauling?

I saw that Howard closed the shop till winter 2010 so I was wondering if someone can recommend me where to buy the gaskets or rings for this overhauling.

[Trerophy]

The Shop is open.
O ring 10 = on some engines the cooling water comes up through that way.
Oil in gearshift well may have come from engine breather.
Seal 7 was the trouble with mine.
Replace sump gasket, o ring, seal, and o ring on top of leg also haylomar or similar around top of leg and its o ring.