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Head Cleaning & Valve Adjustment


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Posted
While going through the Onan "Service and Parts Manual" I came across their recommendation that the valves should be adjusted after about 200 hours of operation. Cleaning of the cylinder heads was also recommended at that time. I'm in the process of assembling the gaskets and material to do the job and want to make sure everything is on hand. So far, this is what is on the list. Is there anything missing? Head gaskets Valve cover gaskets As for the head cleaning, how do I get the carbon deposits removed? Wire brush? Any other suggestions besides what would appear in the manual would also be appreciated.
Posted
Small hi speed wire brush works great. It's aluminium so don't press hard or stay in one spot very long. You can also just take a gasket scrapper and remove the bulk of the build up if muchof anything is there. If there is just some very thin/light char inside the head don't worry about it. I normally don't see much build up unless it's burning some oil or other byproduct that sticks in the turns and goos up stuff. But just scrapping it out is sufficeint. The key is to not leave any small points of residue or ridges in the build up as this could lead to a hot spot that will cause pre detination and over heating as the small surface will get red hot and ignite the mixture before it's supposed to. Pay atention to the valve guides while your in there. While the valve is open, see if there is much side play in the valve. This will lead to oil consumption and lose of comp. and power.
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