Saving Old Seagulls

Thanks - I've found Caustic Soda in the US. You can get it at Tractor Supply as Roebic Heavy Duty Crystal Drain Opener, but it's a bit more rare here than in Europe.
What did you use as the plug for your tank?

Also, If I choose to dunk the whole tank in a bucket of Caustic Soda, will it remove the ...

Unfortunately there was no wind this weekend, so couldn't take my sailboat out but got down to a couple of jobs on my Seagull and the boat itself. I did try to fix the leaking exhaust per one of the other posts I've seen, by creating a ring of DAP 230 Exterior Ultra sealant pushed into the gap ...

Hi,
In rebuilding my Century Plus from 1965, CPCL, I've cleaned up the coat of black paint that a PO had afflicted the fuel tank and like its original brass/lacquer, and rather bashed-up, look. But I have persistent fine black powdery gunk visible in the fuel line that keeps coming back - see the ...

I've been thinking about oils as well and have ordered some Redline fully synthetic, biodegradable watercraft 2-stroke oil on Amazon that should arrive for next weekend's activities. Will let you know the result - going to run my CPCL at 1:16 with it.

Jon - thanks for your comments. I saw "wipe its nose" on a previous post on the forum and should have been more specific; I meant wiping the grey gunk that drips from the exhaust after use, and in my case, also from the leaky exhaust/lower unit junction. It's clearly unburned fuel and 2 stroke oil ...

Progress report:
Last weekend I received a new piston and rings, and some Whitworth tools. I completely deconstructed my Seagull down to its major components and cleaned everything with kerosene, wire brushes and whatever it took. The cylinder head came easily off the block and Jon was right - well ...

.. The piston rings were intact when I first removed the block from the crankcase- I broke one of them removing the ring from the piston. Did not realize how fragile they are. The erosion was under both rings as shown in the photo. No evidence of scarring of the cylinder itself.
I was able to work ...

Hello everyone,
Thanks to your help I was able to break down my Gull, with judicious use of heat, WD40 and a few taps with a wooden block( we have a heatwave here in Charleston - 100 degrees F and 100% humidity- so it was hot work). All the fasteners yielded quite easily and I used regular US ...

Charles and Michael,
It'll take me a week to get back to work on my Seagull and be able to follow your sage advice. I had to leave it partially dismantled with the exhaust not yet released. This weekend I delivered one of my sons to College, so it will have to wait for next weekend.

Iain.

Added a photo
and another

Thanks Michael,
Prying the driveshaft off the crankcase is the most promising, but I'm stuck. I can get a big screwdriver between the two and pry upwards about a centimeter, but the exhaust is pivoting wrt the block on the forward indentation of the exhaust tube, so the whole power block is tilting ...

Thanks Michael,
Trying both of those now :D
Neither has yielded easily - I can't work out what's holding it together. Loosening the two bolts under the crankcase was easy and the whole power assembly lifts a couple of millimeters, but the exhaust axis is preventing further movement. Likewise ...

Thank you.
The nuts holding the powerhead onto the crankcase have all yielded very easily to a 7/16" US 6 point socket which had a very tight fit, so that has given me some confidence. As has the screw holding on the clamp to the exhaust tube. So I'm going to try to remove the powerhead today with ...

Thanks everyone once again for your helpful comments. I've realized I'm going to need a set of Whitworth tools (5/16 BSF) before attempting anything on the head/block, and will have to special order those in the US. I don't want to burr up the edges of any fasteners... From Stelios' response its ...

Hello everyone. The parts are on their way from the UK and I've been reading as much as I can about changing piston rings, which must be the main culprit. I was able to extract better performance from the engine adjusting the spark plug, taper needle depth and fuel mix ( it likes 16:1 better than 10 ...