Paul,
This portable has hidden issues, moron, pseudo mechanic stripped the whole crankcase down as the engine was not starting mainly because fuel **** small filter was obstructed, plug gapped too tight just 0.5 mm along a faulty ground ignition coil issue. Used cylinder head gasket, manifold gasket, lower base gasket & crankcase matting surfaces has been stupidly resealed with mega gray silicone.
Have not tested the engine at load while pushing a boat after the WP has gone through a exhaustive maintenance service, actual exiting water through peeing port is so hot that you could prepare a nice tea with it, imagine the front handle being more than warm when held.
Seems the mega gray silicone overdose has clogged some internal water passages and now engine cools much less than it should. Positively sure it's a overall gaskets/crankcase mating surface issue. Tuesday will test the engine again, if still overheats will dismantle power head down, check for scored cylinder wall, piston, piston rings cond. If shot will order a 0.5 mm piston/ring kit. Will post results.
Happy Boating