Saving Old Seagulls

Here in Greece my friend and also member of this forum (Manos) has a piston of a curlew but it's not in the best condition. The rings are stuck. If you can't find a piston you could try this piston but it would require a lot labor to remove the stuck rings.

Thanks for the offer Stelios. Much appreciated. John is back on 5th August so will drop him a line then.

You are welcome
On 5th? Oh, I knew he was back but he must have left again. I hope for vacations.

I am wondering how on earth did your piston brake so badly

Yes, I think John was back and then off again for a few days.

The piston.... most of the shock from knocking it out must have been taken up by the wrist pin

Would probably have been better to disconnect the big end, remove the head and take out the piston + con rod through the top avoiding the corrosion.

I see.
Now about removing the rust from the bore have a look here

viewtopic.php?f=2&t=4217&hilit=cylinder+hone

The Curlew saga continues.... so I got a new piston kit from John when he got back, cleaned the bore up somewhat and cleared out the water jacket as best I could. Put it all back together and thankfully it ran beautifully... like a mouse eating paper... relatively! After a run in the tank we took it out on a fresh water lake - all good. Then a few runs at sea - still good. After every run out it was flushed at home with fresh water. Then after being laid up in the garage over the winter, first run out - no water from the tell-tale, not a drip - old problem has returned. Water readily flowed out of the exhaust on a reverse flush so I reckon the blockage must be as before - around the cylinder block water inlet (below the exhaust port looking in from the head). Contemplating what to do, that very same night we found an almost new (!) cylinder block on ebay... So before I fit the new block I was wondering is there anything I can do to add some protection to the water jacket lining while its still fresh? I've used Hammerite Kurust before but not sure how it would react with cast iron. Any ideas much appreciated.

I see no reason to replace the block unsell it is cracked or corroded bably around the ring that seal the compration together with the cylinder head.

So it is some rust that blocks the pipe most probable. I would remove the exhaust, the water transfer tube and fitting and see what's wrong. If that cures the problem then phosforic acid in the waterways for, say half an hour. That kills rust. Then baking soda solution to kill the acid. Then regular use and flushing. When store do the phosphoric acid trick again, baking soda and run it for 30 second dry before storing it for winter to evaporate most moisture from the waterways. Then seal with grease the water outlet until next summer. That should work.

Seal the motor in plastic and include kitty litter. Kitty litter will absorb any moisture. Run the motor dry first.

For that matter you can put kitty litter in your car to stop windscreen fogging up overnight.

That accounts for the smell!

So that's acid, soda, run dry and then kitty litter... many thanks everyone!