Covers off and I have never seen a motor with heat pealing paint right back to the carb.................ever!
It turns over so nice so apart it comes and I found a pleasant surprise in that everything is as should be except for head gasket which makes sense
Pistons, rings and bores are mint.
Cleaned up nicely. No blockages or anything in water jacket. The problem will be either the impeller or the join (Fold) not done up tight so cooling water leaked before getting to engine riser pipe into block.
I have a stock of gaskets for these things, a purchase made many years ago so back together it goes. There is no knowing how it will run until I borrow a test prop. This to decide if new rings are required. I have found the cause of over heating which is evident.... The screws snapped off on the water pump housing due to salt. AHA!....take the block off! Took 4 hours to get the drive shaft out of the crank then smooth sailing again. All lower galleries now clean and a light (Factory) splash of paint I scratched all of the blistered paint off with a small screwdriver and 4 beers. Got into every crevice.
New impeller and saved everything else. Gearbox holds pressure.
Carby pulled down and it is a STENCH!...............new kits on hand no probs. Plastic float as well.
Ignition was how I guessed even though it had good sparks. I have prepared one from my recon boxes earlier.
Very nice work C.I. Did I understand you to say that you have some of the factory paint they used for the water passages in the motor. I'm thinking that might be just what is needed in the Seagull water jackets after chipping them out, and treating with a phosphate solution maybe that would give those pesky Century blocks a better chance of surviving a little longer.
The red stuff in the water passages and exhaust plenum is from the factory. I have absolutely no idea what it is not even if an actual "Paint".
I do know that entire castings, before any machining, were treated with it. Low hour motors always have it intact which makes a clean out job look really
This wee bloke has forced me to go the whole nine yards albeit in silly stages chasing the elusive blockage. Should have just taken the power head off from get go. A motor presenting as cooked as this should have been approached in that way (kick self). A bit lame but looking back it was a case of saving unnecessary gasket reserves usage I think.
One thang to note guys! The gaskets removed so far contain, what I think, is Asbestos. It would pay anyone working on these to take the proper precautions.
The next one waiting is a nice clean Johnson folder, 1968 I think. I will run it first and take things from there. Later with that one aye.
Carb kit in with modern plastic float and new coils etc for the magneto. I only have two new coils left now......
Found my big box of gaskets to fit the power head on to the leg. Mission as BIG box. Check this out re base gasket and 3Hp verses 4Hp.
I have to cut a hole in the correct place (Nearly missed it as 4Hp gasket). The 4Hp has the exit water gallery around the main 360 degrees and the 3Hp is only 180 Degrees. No, the 4Hp block will not fit a folder trunk. The water pump pipe is totally a diferent system.
I scratched all of the blistered paint off with a small screwdriver and 4 beers. Got into every crevice. 
