Lakester
Chief Petty Officer
- Joined
- Nov 17, 2007
- Messages
- 428
hello,
after tinkering on my 1971 85hp evinrude engine, addressing both mechanical stuff [bolt & screw tightness] and some housekeeping stuff [cleaning, cleaning and cleaning some more
] i noted a crack in the port cyl head to thermostat housing water hose. an old crack for sure. its on head side end of hose, maybe even spraying some. so since one of its O-ring clamps was rusty with broken end, i removed hose for replacement and also the cyl head plate having noted some blockage once hose was off.
at the lower head to thermostat hose connecting port [head side] there was about a 1/3 blockage of the oriface in head's nipple with some white stuff. not too hard, almost semi-powdery. i assume some sort of corrosion. was not in thermostat plastic port, nor in the head's water passageways, however quite a bit of it is between the cyl head plate and gasket [plate to head gasket] in its shallow channels. or at least a similar substance???
*** any idea what this white stuff is. and how it got there? i am assuming the plate has not been off head before. as best as i can tell the head's plate is competely sealed. no air or water gets between it and the gasket that seals it to the cyl head.
once the gasket was opened and more or less removed to gain a visual access to cyl head water passage ways, i noted a wet brownish substance coating entire surface. not thick, but it is scrapable with screwdriver tip, etc. i assume it is on surface of most of engine's water passageways.
*** what is this stuff? i am assuming also some type of corrosion. passageways appear to be open and clean other than for this substance.
i also note that under the factory engine paint is a reddish-brown almost primer like paint. it is also on the inside of the water passage ways as is also what i see around the spark plug holes, too. i note some of it scraped off when cleaning the wet substance off the cyl head's water passageway.
*** is it important to repaint the cyl head's water passageways? i certainly doubt i can do it on block between cyl wall and block wall.
*** should i flush the engine's water passageways since i plan to remove the thermostat inners for inspection etc. if so, what is best procedure? is there an engine flush treatment recommended?
thanks. any thots on opening up an old engine's water passageways after the effects of use and ol' father time... and best-to-do ideas would be both helpful and greatly appreciated.
as a further thot, i would like to pull the cyl heads on both banks. clean head bolts, chase block threads, reset new head gaskets and torque. but since engine runs nicely, and a bore inspection showed very clean piston crown's... with no carbon build-up [carbon guard used religiously over its life] i am considering not doing that at this time. just the hose connections, thermostat, and the one head and its water passageways. and then button 'er up. yes, no?
regards,
lakester
after tinkering on my 1971 85hp evinrude engine, addressing both mechanical stuff [bolt & screw tightness] and some housekeeping stuff [cleaning, cleaning and cleaning some more
] i noted a crack in the port cyl head to thermostat housing water hose. an old crack for sure. its on head side end of hose, maybe even spraying some. so since one of its O-ring clamps was rusty with broken end, i removed hose for replacement and also the cyl head plate having noted some blockage once hose was off. at the lower head to thermostat hose connecting port [head side] there was about a 1/3 blockage of the oriface in head's nipple with some white stuff. not too hard, almost semi-powdery. i assume some sort of corrosion.
was not in thermostat plastic port, nor in the head's water passageways, however quite a bit of it is between the cyl head plate and gasket [plate to head gasket] in its shallow channels. or at least a similar substance???*** any idea what this white stuff is. and how it got there? i am assuming the plate has not been off head before. as best as i can tell the head's plate is competely sealed. no air or water gets between it and the gasket that seals it to the cyl head.
once the gasket was opened and more or less removed to gain a visual access to cyl head water passage ways, i noted a wet brownish substance coating entire surface. not thick, but it is scrapable with screwdriver tip, etc. i assume it is on surface of most of engine's water passageways.
*** what is this stuff? i am assuming also some type of corrosion. passageways appear to be open and clean other than for this substance.
i also note that under the factory engine paint is a reddish-brown almost primer like paint. it is also on the inside of the water passage ways as is also what i see around the spark plug holes, too. i note some of it scraped off when cleaning the wet substance off the cyl head's water passageway.
*** is it important to repaint the cyl head's water passageways? i certainly doubt i can do it on block between cyl wall and block wall.
*** should i flush the engine's water passageways since i plan to remove the thermostat inners for inspection etc. if so, what is best procedure? is there an engine flush treatment recommended?
thanks. any thots on opening up an old engine's water passageways after the effects of use and ol' father time... and best-to-do ideas would be both helpful and greatly appreciated.
as a further thot, i would like to pull the cyl heads on both banks. clean head bolts, chase block threads, reset new head gaskets and torque. but since engine runs nicely, and a bore inspection showed very clean piston crown's... with no carbon build-up [carbon guard used religiously over its life] i am considering not doing that at this time. just the hose connections, thermostat, and the one head and its water passageways. and then button 'er up. yes, no?
regards,
lakester
