Service / water cooling jacket 90hp Yamaha Outboard

[jamfordz]

Do you need to competely replace a water cooling jacket on a 90hp Yamaha outboard or can you service and fix up the old one by cleaning and treating it say a paint system ?

Thanks for all your help...have just started to use this resource its great !

[boats.net]

You can clean them, but if they are pitted bad then replace them. Paint probably wouldn't stick very good and if it came loose then could plug cooling passages.

[Ken]

jamfordz,
I don't know how old your Yamaha is, and I am assuming you are talking about the head water jacket.
Yamaha paints the interior of the water jacket with a corrosion resistant coating, which, of course, can get clogged up with mineral/salt/sand deposits. The head can be removed and the deposits cleaned out with brushes (not wire) or high pressure water hose. You don't want to scratch up the protective coating.
If the head has rusted in places bad enough, then replacement is probably in order.
Good luck [img]smile.gif[/img] ,
Ken K