Yamaha 9.9hp indicator holes blocked.

[jimthesail]

Ahoy !
Having lost water from 'pee' hole have had to remove head on Yamaha 9.9hp (white cowl) F9.9AE.
All clogged with what looked like washing detergent ! Cannot find drilling in block to let water in to chamber outside exhaust trunks
which in turn has the brass elbows fitted which feeds the P 'ole ! The chamber starts in the block and runs through the head gasket to the head and has two blanking screws at the top under the cam cover Help !
Jim

 

[Beamishken]

The white material your seeing is likely salt/calcium build up & you drain holes are likely blocked the same. Depending how far stripped the engine is you could either put it in a ultrasonic cleaning bath to try & clean it & find the ports or sit it in something like acetic acid to disolve the salt. Alternatively carefully scrape all the galleries until you find the port its likely either full of the same deposits or possibly corroded closed as the aluminium has swollen with corrosion.
It may be worth trying to remove the two blanking plugs and probing via them as they are probably blanking machining holes from manufacture where the ports were drilled

 

[jimthesail]

The white material your seeing is likely salt/calcium build up & you drain holes are likely blocked the same. Depending how far stripped the engine is you could either put it in a ultrasonic cleaning bath to try & clean it & find the ports or sit it in something like acetic acid to disolve the salt. Alternatively carefully scrape all the galleries until you find the port its likely either full of the same deposits or possibly corroded closed as the aluminium has swollen with corrosion.
It may be worth trying to remove the two blanking plugs and probing via them as they are probably blanking machining holes from manufacture where the ports were drilled

Thanks for that. Last night saw an American vid. and the penny dropped ! The connecting holes are in the bottom chamber but point outboard into the exhaust cover plate labyrinth.