Smoke on Startup - Normal?

[Nick1994]

Originally Posted By: grumpy
The real question, neither asked nor answered, is "Does it use any oil between changes?" If the oil is checked before each use, and no oil is required to be added between changes, then the consumption is minimal. It is normal for all engines to consume a bit of lube, it would be abnormal for an engine to not consume oil.
Were it mine, I would ignore any startup smoke if the oil level remains consistently in spec. If the oil level rises, be concerned for gas contamination due to carburetor needle & seat failure.
I usually change once a year, and have never had to add oil between changes

 

[steve20]

Nick
I had the exact same issue with an almost new B&S 6.75
I added about an ounce of Lubro-Moly just for the moly sake, not even thinking about the blue puff at start up, & low & behold, no more puff of blue at start up
Steve

 

[Quest]

Originally Posted By: steve20
Nick
I had the exact same issue with an almost new B&S 6.75
I added about an ounce of Lubro-Moly just for the moly sake, not even thinking about the blue puff at start up, & low & behold, no more puff of blue at start up
Steve


The reason why B&S flathead 675 puff smoke during start up is due to (a) too rich of mixture during initial/cold start up, and (b) those flatheads come designed without valve stem seal, so some oil will definitely gets sucked past the intake valve guide.

Adding additives (such as thickeners will only mask the smoke, just like most of the motor hunny and similar). The issue is still there.

Q.

 

[Hokiefyd]

Very normal in my experience two two small Hondas (a GCV160 and a GXV140). Some oil will get into the cylinder and puff out when you start it. No big deal at all. You can replace the valve stem seals pretty easily, but that won't change the behavior here -- oil is not sitting on those seals to leak down (as it sometimes is in a vertical cylinder engine), and the valve cover area of the engine doesn't see much oil. This isn't like a flathead engine where the valve stems are internal to the crank case.

Here's the inside of my 12 year old GCV160 last year:

The valves are at the top of the valve cover area and just don't see much oil. It's kind of a neat design, how they use a single cam lobe to operate both the intake and exhaust valves.

 

[Kamele0N]

Originally Posted By: Lubener
I would bet if you remove the head after it has sat,you will find some oil has seeped by some sightly worn rings.


And slightly oval cylinder...weight of piston over time