IO550 idle issues

[Bolter]

10 minutes ago, Pnwflyer said:

Hi!  Any good outcome of this issue a while ago?  Kind of struggling with same issue on IO550D.  After start, acts like it’s going to idle and then starts to die.  If I catch it with elect fuel pump, it will stay alive.  Have to do this for a few mins then it idles fine.  But, when taxiing, adding power gives a pretty good hesitation and it has another go at trying to quit. Once it’s warmed up, it only hesitates when going from idle to about 1200-1500 for taxi.  Amazingly, there is no hesitation or preponderance of trying to quit at all while airborne and at idle. Just wondering what you found out anything. 
 

full disclosure here: this engine is on a c185….i just saw you had a similar issue with a 550 and wanted to pick your brain!  Thanks!

Fellow PNW flyer here.  My personal experience was traced to fuel pump and divider wear from age, and leaking internally.  Replacing these parts AND proper system tuning, fixed it all.  You already confirmed good plugs and igntion wires, I assume.

[Mufflerbearing]

On 3/14/2025 at 4:08 PM, Pnwflyer said:

Hi!  Any good outcome of this issue a while ago?  Kind of struggling with same issue on IO550D.  After start, acts like it’s going to idle and then starts to die.  If I catch it with elect fuel pump, it will stay alive.  Have to do this for a few mins then it idles fine.  But, when taxiing, adding power gives a pretty good hesitation and it has another go at trying to quit. Once it’s warmed up, it only hesitates when going from idle to about 1200-1500 for taxi.  Amazingly, there is no hesitation or preponderance of trying to quit at all while airborne and at idle. Just wondering what you found out anything. 
 

full disclosure here: this engine is on a c185….i just saw you had a similar issue with a 550 and wanted to pick your brain!  Thanks!

Yes, the challenge has been sorted.  The biggest and first thing I did was install fine wires top and bottom.  10/12 Champion spark plugs failed the ohm test.  Then I did have the fuel pump replaced and then what I later learned the importance of having the mechanical fuel injection system tuned annually.

With all of these things, the plane runs perfectly.