1977 9.9 hp

[alankesaussie]

Hello all I am new to this forum I am writing from Australia.

I have a Johnson 1977 9.9 HP O/B in very good condition has had little use.

Scenario as follows water is flowing from tell tale hole at idle no problem good flow etc but no water from two exhaust holes immediately below the cowl hood catch.

I replaced the impeller and tested the pump in a barrel with a drill turning the shaft ALL GOOD then I replaced the thermostat which was a bit corroded but it seemed to work in a hot water bath but replaced it anyway to be sure. I let the motor run for a few minutes with both earmuffs and in a barrel with water well up the leg both times no water from the exhaust. I read that 5 minutes is the max to allow before overheating issues start I also fed nylon snipper cord into all orifices and pressure washed same and introduced compressed air from pee hole etc all seems clear.I know my way around engines but not really outboards motor is starting, running and idling sweet as a nut so I don't suspect blown head gasket.

Any suggestions would be most welcome thanks in advance
Alan

[Solarman]

Alan, if you have a laser style temp gun, run motor in the barrel, or on muffs, and check temps around all the cylinders. If there are any areas that are getting hot, you may have blockages in the water pas-sages near those areas. If the motor stays cool then give a run in the water. Sometimes moving forward in the water forces more water through the system, if slight blockage it may be pushed out?
Otherwise, you may have to flush with a corrosion cleaner in the barrel, with hopes that it will clear the blockages.

Good luck. Let us know if you find anything.