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I'm rebuilding the water jacket and head of a 1987 3 cylinder 90 ETLH 2 stroke Yamaha outboard. It had a small water jacket leak... I can't handle leaks. The leak was between Number 30 and 31 in the attached picture.
Should I use new bolts or is it OK to re-use the old ones? We're not talking very much torque here and they are grade 8. I've chased out all the female threads with a new tap and Kroil to get all the old grunge out of the holes, and plan on using compressed air to clean them prior to final assembly.
The head is aluminum and the VERY expensive OEM bolts appear to be some sort of chrome alloy - VERY shiny - and nothing like I can source locally, even though they are grade 8.
Also, should I use a high temp Nickle anti-seize, or is a drop of motor oil - with less final torque acceptable? The threads on the bolts were bone dry from the factory.
The reason I ask about the anti-seize is that I got to go through the wonderful experience of extracting two VERY corroded bolts that snapped off flush in the head. I managed to save the threads but it took 3 HOURS to get the little boogers out.
Good times!
Should I use new bolts or is it OK to re-use the old ones? We're not talking very much torque here and they are grade 8. I've chased out all the female threads with a new tap and Kroil to get all the old grunge out of the holes, and plan on using compressed air to clean them prior to final assembly.
The head is aluminum and the VERY expensive OEM bolts appear to be some sort of chrome alloy - VERY shiny - and nothing like I can source locally, even though they are grade 8.
Also, should I use a high temp Nickle anti-seize, or is a drop of motor oil - with less final torque acceptable? The threads on the bolts were bone dry from the factory.
The reason I ask about the anti-seize is that I got to go through the wonderful experience of extracting two VERY corroded bolts that snapped off flush in the head. I managed to save the threads but it took 3 HOURS to get the little boogers out.
Good times!
, but I got it along with the engine) says to use a drop of Yamaha two stroke oil on each bolt. Then again it was probably written in the 70's, long before teflon paste and cell phones. 
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