White Smoke & Misfiring

[MarkyH]

Had a long running problem with engine seemingly overheating and producing huge amounts of white smoke (steam) when engine under any kind of load. Flow from pee hole was also intermittent when underway but fine when running on muffs. Changed impeller, removed exhaust cover off side of engine and cleaned out water holes (some were really gunked up). Put all back together and still getting lots of steam and now engine is misfiring - like fuel starvation.

Checked plugs - they look pretty dry, no water in cylinders and compression test shows all three cylinders about 100 PSI.

Engine is a 85 AET, it's old but been very well kept and looked after. Anyone else got any experience of this/ideas ?

Thanks

[boats.net]

If overheating then it will go into rpm reduction. Probably need to replace complete water pump. Check exhaust plate for holes corroded through it.