water circulation 9.9 block

Post here for issues with outboard engines (i.e Yamaha 9.9) on PDQ yachts
swithen
deckhand
deckhand
Posts: 10
Joined: Sun May 23, 2004 10:42 pm

Re: water circulation 9.9 block

Post by swithen »

Chet, Chris:

I agree with Terry on the muriatic acid issue and do not recommend it for cleaning cooling passages on outboards. It may work if very dilute, but why risk it when vinegar works. There may be other acids out there which have advantages over vinegar (oxalic, sulphamic acid) but I don't want to risk damaging an engine to research the topic.
I don't think the vinegar treatment should be done frequently. My treatment was done with about 1,000 hours on the clock and I don't see any need to do it more frequently than this.

Colin Swithenbank
Cadenza 36051
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