In the Fall of 2006 I bought at a used Honda walk behind mower with GCV 160 engine. The mower is a 2006 model and I when I bought it, the mower looked brand new. So new that the underside of the deck had just two may be three scratches on it, no green grass stains... it just looked good. I keep my equipment clean but even I can't get it to look that clean anymore.

The mower is great. It starts on the first pull with the choke set, runs great and barely uses any fuel during the 45 minute run to mow my grass. Because the mower looked so new, I used the engine oil that came in the engine for the first 6 cuts, then I changed to Mobil 1 10W-30 to finish out the 2006 season. Before putting the mower away I changed the oil and lubed the cylinder with fresh engine oil per the instructions in the manual then set the piston and crank so that the valves would be closed for the winter.

This spring if I remember correctly the mower started on the second pull, smoked for 10-15 seconds as it burned off the oil in the cylinder then ran fine. Now that the mercury is rising when I start the mower, still choke on, I get a healthy puff of light blue smoke until I release the choke.

The cold engine won't start easily without the choke, but what concerns me is that the smoke is light blue and not black. Although is might be light grey. I am color blind and have trouble with the color blue.

Is this something that I should worry about? I store the mower in my shed, when I am finished mowing I let is slow idle for 30 seconds before I shut it down and I turn on off the fuel at the shut-off valve.

No, I would not worry about a little smoke when first starting. It's possible that some oil may seep around the valve guides and cause a few puffs of smoke when first starting.

Monitor your oil consumption, if it becomes excessive then you might need to look into it. An air cooled engine under a load can use up to 2 ounces of oil per hour of run time and still be considered normal. Overhead valve engines generally will use less oil then their L head counter parts.

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Thank you for the quick response. I was thinking the same thing, I just wanted a second opinion.

I am very particular about my equipment and although I know just what it is, I'd like for it not to smoke. I haven't checked my service manuals yet, do you know if the valve guide seals are easily replaced?

The intake valve is the only one with a seal. The hardest part about replacing the seal is getting the valve cover off. Honda does not use a gasket on the valve cover but rather Silicon sealant.

The valve spring retainer can be removed and reinstalled by hand with no special tools, just make sure the piston is at TDC so the valve wont accidentally get pushed all the way in the cylinder.

This short puff of smoke is pretty much normal after these engines have a few hours on them. Some of the oil may be entering via the exhaust valve which has no seal.

:thumbsup:

Well may be it is best to let well enough alone. Thank you.