no compression cyl 1&2 912 ULS

[Delta Whisky]

I've had a stuck valve - twice - and staking it fixed the problem. In both cases it was #2 cylinder. There may be something about the front cylinders that makes them more prone.

[Slyfox]

I've had a stuck valve - twice - and staking it fixed the problem. In both cases it was #2 cylinder. There may be something about the front cylinders that makes them more prone.

just what I was thinking. take and rap on the end of the valve and check for compression, you probably will feel the difference when pulling the prop through. afterwards if the engine will run take and put about 2 ounces of mmo Marvel mystery oil in the fuel for every 5 gallons and run it that way for a while and it should clear it up. another would be to decarbon in the same way. maybe a whole can of cleaner(seafoam) to a small amount of fuel maybe a gallon of fuel. good luck

[turboturner]

Thx for clearing that up DW. I just learned that the 912 is best run at high RPM: 5400+. My (ltd) research seems to support this. I usually run mine in the 5200 range. This might help explain carbon buildup. Comments, anyone?

[Delta Whisky]

Carl - I sure hate to put this out on the internet but in my POH I wrote that when on 100LL, the minimum recommended cruise RPM is 5200. BUT - I can't locate where I found it originally so take it for what it is worth. I will say that having written it, I routinely fly at 5200 -5300 (and, like 5300 the best). I'm pretty sure that the 5200 for 100LL is for scavenging purposes and therefore wouldn't apply to mogas. BUT - don't anyone quote me - I don't want to be the one that started an internet rumor!!