40+ loosing power

[david doyle]

Phil:

While I see your point about not messing with something that is working, I just took my current block out in the sun to finish cleaning out the galleries. Lo and behold what I thought was a paint scratch turns out to be a crack in the block. If one half of the block is cooled and the other half is not (due to blocked galleries) the iron almost has to crack.

[phil]

I believe that most block cracking that occurs in salt water motors is due to the expansion of corrosion deposits as the salt,and iron combine in a damp environment. It is a force of expansion at least as powerful as water freezing in an enclosed space. This is the sad story that is played out repeatedly when people search for antique inboard motors which happen to be built of cast iron. These days almost every one you see has a crack somewhere on exterior of the water jacket.

It seems to me that stabilizing that situation is more important as a cause of causing cracked blocks than a supposed uneven heating within a water jacket that is still circulating an adequate stream of water.

Of course there are other possibilities to explain cracks in a block such as; rough handling, uneven heating during broken screw or stud extractions, etc

[anne-marie]

hi seaguys
i thought i had repaired the litle forty by changing head and cancrase gasket after cleaning waterways, but the fact is that it was piston rings.
the motor goes well, a very nice quiet sound, but 15 minutes after, facing the lock, it weakened again. damned dancing rings!
well, i ordered new ones, but can you direct me on the way to change it safely?
thanks guys

[Stelios_Rjk]

Hi,

are the water ways of your cylinder clean as in the picture H-A had posted?



When the engine stops, is it more difficult than usual to turn the flywheel with bare hands?
Is the engine damn hot when it stops?

If the rings had danced your cylinder or even the whole crank assembly would be ready for the scrapyard.

Please answer the questions above to understand what's going on.

[anne-marie]

hi, so when the engine stopped, the flywheel was hard to turn and a metallic noise was to be heard.
the engine was damned hot, and my waterway was full of rust.
so i clean it, put new copper gasket, new piston rings, with the good method (boiling the pin in hot water etc)
the cylinder block seems ok no scratch in it.
i even have a new spark plug set,
now the flywheel is turning smoothly, but the little forty still doesnt start..maybe the old two weeks fuel?

[Stelios_Rjk]

My Seagulls runs even with 6-8 months old fuel so that's not your problem unless the fuel has loose much of its strength due to extreme evaporation.

So this time your engine just stops after 15 minutes and after that the flywheel turns smoothly by hand. Right?

What about temperature when it stopped?

[Horsley-Anarak]

My Seagulls runs even with 6-8 months old fuel so that's not your problem unless the fuel has loose much of its strength due to extreme evaporation.

Stelios have any of your Seagulls flown down from you balcony onto the back of a boat yet?

They can behave very differently when worked hard and under load.

H-A

[Stelios_Rjk]

Unfortunately I am stuck in Athens! And there are other silly legal things that in case the port authorities catch me with a Seagull in the back of my boat, I will be in big troubles (fine etc).

Yes, 6-8 months old fuel won't go to the sea. When I tried that with a suzuki dt15 I saw difference after changing the fuel.