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Old 08-24-2021, 07:55 PM
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Default K 70 Erratic and Unreliable starts

I am helping or trying to help a friend with a brand new SN 176 or 196 K-70. Initially I was using kero and would get one good start and then the next one would hang at 28 or 29k stage 3 and then roll back and just never recover. I found that I would get more good starts with UAT horizontal versus vertical. I seldom or never got a succesful start with uat vertical. I switched to diesel and got a slight improvement in the number of successful starts vs non sucesses. Eventually I tried removing the fuel filter and that seemed to be much better and could get good starts with UAT horiz or vertical. I then installed a jetcat filter and the starts were the same as with no filter. Up to this point I was starting on a test stand with the entire fuel system from the airplane. I then installed the engine and fuel system in the plane with the jetcat filter. The filter is in the plane at approx a 45 degree angle down from vertical. I have the uat in the plane vertical. I made a couple of acceptable starts in the plane at home on the driveway. I then took the plane to the flying field where the first start attempt was very very slow to accelerate from 30k up to 55k where it did show running on the GSU. Even thou it showed idle rpm and "running" the engine would not accelerate AT ALL, None whatsoever. It was not sounding right at all with sort of poping sound (hard to describe). I shut it down, cooled it off and made another start attempt which got to running much quicker (more like normal), engine sounded good and smooth at idle and accelerated with throttle advance. Made a normal flight with no problems. Did not have time to try another start or flight so I have no idea if it would have started normally or not. For my next attempts I am thinking of switching back to kero since it did start faster and accelerate more quickly from light off to idle ("running"). I am am also considering putting the UAT level horizontal of much closer to level (less than 45 degrees up from level). Also considering putting the fuel filter vertical or as close to vertical as I can. I failed to mention that with the kingtech provided filter even when mounted vertical as required in the manual I was getting lots of small air bubbles in the line during starts. This ceased with jetcat filter installed. Any ideas or suggestions on how to get better more reliable starts. By the way I am in Denver Co, 5500" feet elevation, temps in the high80's to low 90 and mid 90's which puts density altitude up round 7500' feet to 9000 feet or so. And setting or parameter changes suggestions would be greatly appreciated. Thanks
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Last edited by turnnburn; 08-24-2021 at 07:56 PM. Reason: added text