Originally Posted by
NancysToy
That's too bad. White smoke would indicate water, and black smoke unburned fuel, but blue means oil. The intermittent nature of it is odd. I suppose a misfire could cause such a thing on a well-worn engine, but it is not common. A tight engine would not normally do this. If the problem is rings, head or cylinder damage, or valve guides, it is usually more constant. If it is one of those things, a compression test and maybe a leak-down test may be in order. The only other thing I could think of would be a bad scavenging pump, which allows oil to build up in the crankcase, and be forced past the rings at times. That will usually show up as eventual lubrication problems, as the oil tank runs low. I'll keep my fingers crossed for you.