excess fuel in oil analysis?

[GeorgeC]

My most recent annual was in February of this year. The oil analysis was unremarkable, except that Blackstone called attention to the fact that there was an unusual amount of fuel (3.5%; normal is <1%) in the oil. At the time, I'd ascribed that to my clumsily overpriming and flooding the engine on the morning I flew it to annual.

I just got the results from my oil analysis in August (I know, it's December...), and the fuel is down to 1.3%. I don't prime much in the summer, so that excuse is out.

What else could explain the fuel in the oil?

O-200 running E0 mogas.

 

[Dan Thomas]

My most recent annual was in February of this year. The oil analysis was unremarkable, except that Blackstone called attention to the fact that there was an unusual amount of fuel (3.5%; normal is <1%) in the oil. At the time, I'd ascribed that to my clumsily overpriming and flooding the engine on the morning I flew it to annual.

I just got the results from my oil analysis in August (I know, it's December...), and the fuel is down to 1.3%. I don't prime much in the summer, so that excuse is out.

What else could explain the fuel in the oil?

O-200 running E0 mogas.

Poor atomization from the MA3 carb? They're famous for that. Are the exhaust stacks sooty? Are you leaning properly? Is there a weak mag or a few bad plugs that start the engine running rough earlier than normal when leaning so you end up too rich? Is the primer in and locked?