Approx. 3 years ago I sent my Rotax 912 carbs for the 600 Hour overhaul, picking up floats that suffered the sinking syndrome. I replaced the floats last year on the warranty scheme and have just opened the float chambers as part of my annual inspection (18 hours after changing to non sinking floats).
Please see attached picture.
I think the yellow tinge is from percolation of the MOGAS I was using, fixed by using UL91 (not present in the other carb.)
I'm concerned about the line that appears to have been causes by the float fowling the side of the float chamber. I'm sure it wasn't there last year as I'd have spotted it. Is this something anyone has seen before?
I'm at a bit of a loss as to know what to do.
Ideas so far:
1. Take off the bowl and fill with fuel to see how the float bobs around/compare to the old float
2. Put the float in fuel but without being mounted on the guide to see if it has a heavy end
3. I've already weighed all four floats their each 3.2g give or take a nats whisker
4. Could the float have been incorrectly seated/slightly stuck when I refitted last year? The plane doesn't start as well as it used to which I thought was due to percolating fuel. Maybe I should try some cold start cycles to see if its still needs to crank for a few seconds before firing. Hot start issue was fixed by using UL91 fuel rather than MOGAS with ethanol in it
5. Continue to fly and monitor every 5 hours, photograph each time
I'm really not to sure what else I can do about it. There is no obvious damage to the float (not used an eyeglass to examine as yet.
Any advice greatly appreciated :-)
8722_1_20210711_125816.jpg (You do not have access to download this file.)
