Flushing Tohatsu OB's

[Sea Rider]

My beloved 18 is undergoing a 600 hour full preventive maintenance, it's correctly flushed after each outing on muffs, for at least 10 minutes, while engine is on running at fast idle. Assume all Tohatsu owners flushes their OB's after use specially the ones used on salt waters. If so share your flushing experience. Do you flush your OB...

1-On muffs, with flushing attachment, barrel flushing.
2-For how long
3-While OB is on or off
4-If head gasket is removed after say 300 worked hours, do you expect to find all water passages clean, medium clean, salted, crusted, corroded ?

This will tell a lot about flushing method used, time spent while flushing and if flushed ON/Off...

Happy Boating

 

[Sea Rider]

Although you can flush your OB with fresh water as long as you want using any of the 3 mentioned flushing methods, running hours will be decisive in the condition you will finally find internal cooling water passages, thermostat when opening the Pandora Box.



This is what was found when stripping lower powerhead. Half of lower engine base gasket was missing, burnt out by exhaust.



Thermostat is the only part that received a previous full maintenance at first 300 worked hours from new, now has 300 more.



Have not stripped down cylinder head due to having 2 bolts found seized, will need to be heated up with a propane torch to remove them easily and don't break bolts on powerhead threads. Have already made my mind that water passages will definitely not be found in a immaculate clean cond...

Happy Boating

 

[Sea Rider]

After paying a visit to the the torch man, finally managed to pull out remaining seized nut on crankcase and extract remains of 3 bolts that broke when trying to disassemble head. At just $15 for one hour specialized work, is bargain money best invested. Going back to the original post, if it were your OB and have water flushed it at high pressure for say 10-15 minutes after each use, which internal cond would you expect to find once Pandora Box is opened. Comment your thoughts about water flushing..

Happy Boating

 

[pvanv]

Luis, even fresh water can corrode aluminum, after enough time. Flushing gets the salt residue out, but the aluminum will eventually corrode anyway. The best flushing will be with the motor running, so the thermostat can cycle open/closed as needed, flushing the cooling passages in the head area.

 

[Sea Rider]

This 2 year old 18 OB is in mint looking and working condition...




As we say down here..Outwardly Flowers, Inside Tremors....Pics speak for themselves.













Will need lots of hand labor, time, patience to rebuilt that 18...

Happy Boating