Oil Degreaser For 2 Stroke Outboard Water Passages

[Fitz98]

I have a 2001 Optimax 200 2 stroke.
Over the years a bunch of oil and thick sludge has built up in the exhaust plate and blocked some of my water passages. I was able to degrease the majority of the exhaust plate through the midsection by removing the lower unit and spraying up inside and using a copper wire to help unclog some of the coolant passage holes. Now I want to go the rest of the way and degrease those ports through the cooling system flushing ports.
Anyone have any experience or advice on product or procedure to do this?

Here is a picture looking up the mid section, what you can't see are the 4 coolant passages covered with old crusty oil

 

[ragtoplvr]

If you have that much build up I think an inspection of the exhaust ports would be wise. You might be losing some horsepower.

Rod

 

[1978elcamino]

I would think those passages look normal for a two stroke and probably not worry about it. I would be more concerned about the water passages getting clogged up with debris and salt. Personally, I have ran a high concentrate of vinager and water through the motor with an electric pump for hours and that cleaned out all kinds of crud from the cooling system.