discoloration around rocker

Grass Roots Farmer · Sep 5, 2012

I have just replaced the rocker cover gasket on a Toro Zero Turn with a B & S engine. There was a small oil leak from the gasket. I noticed a brown discoloration around the rocker (I know nothing about engines!) and wondered what it might be. The stain did not scrape off. Has something seared the metal? Hot oil? The engine is about 8 years old, maybe 600-700 hours on the machine.

Anonymous-0 · Sep 5, 2012

I am thinking its a single cylinder Briggs on a Timecutter-judging by the muffler mount strap.

What you see is, I think, burnt motor oil deposits. I guess with 600+ hrs on it the guide is not tight as it once was and part of the exhaust gas is following the exhaust valve guide back into the rocker chamber. (no valve stem seal on exhaust, if I remember correctly.)

I wouldn't worry about it too much. At those hours You have pretty much the expected service life out of the engine and its not practical to replace the head or put a valve guide in it just because of those black deposits. I can tell you manitained it well, you never would have that many hours on it if you hadn't.

Just keep the cooling fins clear of debris and keep the oil level above the add mark and don't worry about it until someother problem crops up.

Grass Roots Farmer · Sep 6, 2012

Hey, thanks for your analysis; my worries are alleviated and I will be happy to get whatever is left in the life of the engine.

discoloration around rocker

Grass Roots Farmer

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Anonymous-0

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