1993 pro-v 200 model p200TLRR overheating

[bassinflats]

Well here we go again motor overheating and a slime build up on the cooling water jackets. Made it two years this time and have been using salt away every week after we come back from fishing. Not even running the boat in salt water, it has been all fresh water this time. It builds up so bad that it cloggs the small holes in cooing jacket. This will be the foirth time I have had this problem, wish a Yamaha rep would come and look at this thing. If they want to call me my number is 407-765-7787, they werent any help last time.Said I had a water pressure problem , well I guess i did since the water couldn't get thru the jackets. Does anybody know if these things have a special coating?The first time the shop bead blasted them to get them clean, the last time I used muratic acid and pressure wased them.I am at wits end here, somebody help me. If i could figure out how to put a picture on here I would.

[rodbolt17]

yes, there used to be a special coating on the internals.

are you really serious?
do you really think a Yamaha rep is going to look at a 20 year old motor?
I try not to even work on the antique beasts.

aluminum corrodes,planes do it,cars do it,bleacher stands do it and outboards do it.

I work on an 89 115 that since about 2000 the heads and water jackets come apart for cleaning about every 3rd year.

even "freshwater" can contain various minerals that lead to scaling.
poor maint just makes it worse.