Engine hard to kill

[rdv]

Does anyone have an IO360 that doesnt want to stop? Mine likes to keep sputtering along and occasionaly, backwards! My theory is that its still getting fuel AFTER we go to idle cut-off from a poorly rigged mixture control cable and glowing lead deposits in the cylinders or spark plugs keep the engine running. Am I on the right track?

Ryan

[testwest]

We have had this happen quite some time ago. I would say the glowing deposits root cause is unlikely, but possible. What do your plugs look like? Do you idle at full rich?

We checked the mixture cable on 201JX, no joy. Eventually we had to send the fuel servo out for overhaul, which solved the problem....but it was not cheap unfortunately.

Check the easy stuff first, like the adjustments on the servo. Good luck and let us know what you find.

[PTK]

Quote: rdv

Does anyone have an IO360 that doesnt want to stop? 

[jsimmons619]

Years ago I had a similar failure to shut down on an IO360 in a Steen Skybolt.  After multiple attempts to resolve the problem, Mattituck Aviation on Long Island, NY discovered that there was an incorrect plug (straight thread vs. tapered thread) in the flow divider manifold on the top of the engine.  As it was explained to me, this plug was permitting air to seep into the flow divider.  This air leak permitted the fuel in the lines to enter the cylinders; even though the mixture had been cut off.  Replacing the plug (correct thread type) instantly resolved the problem.  I don't know if this helps but I wish you well in getting it resolved.

 

[danb35]

If you're still getting fuel with the mixture at ICO, you don't need to speculate about glowing deposits or any such thing--the engine's still turning, so the magnetos will keep sparking.

[rdv]

Sorry guys, I forgot to mention one critical engine condition: this occurs with mixture ICO and mags OFF. This is why I am suspicious of incandescent deposits. My mistake. And thanks for your thoughts thus far.

 

Ryan

[testwest]

In our case, idle cutoff did not actually stop fuel flow....the only way to stop the engine was to turn both mags off.

Ryan you may have two problems, one based on the mag still sparking with the mag switch OFF and fuel still flowing (somewhat) with the mixture in idle cutoff.

Try to isolate the issues if you can....with the engine hot and idling, try to shut it off with only the mags. Leave the mixture where it is. If engine shuts down, the mags are properly grounded. If it still idles perfectly, the mags are still providing a properly timed ignition event, even when the switch is OFF. If it idles crappy, you have ignition being caused by some other source. BTW, if the mags have more than 500 hours since overhaul, they really should be opened up and overhauled.

Good luck with this, it's frustrating but keep after it.

[crxcte]

Turn the fuel valve to off to kill.  I've been doing it for over a year to keep it from flooding and it has ran been running its best since.

[fantom]

Quote: crxcte

Turn the fuel valve to off to kill.  I've been doing it for over a year to keep it from flooding and it has ran been running its best since.

[clh]

Quote: testwest

 

 "Eventually we had to send the fuel servo out for overhaul, which solved the problem....but it was not cheap unfortunately."

I had the same experience....

[Ron McBride]

I had this problem on a twin with continentals occasionally.  With mixture back and advanced the throttle and the engine would quit.

Ron

[rdv]

Turn the fuel valve off, brilliant. Simple solution. I like it too! Thanks for all the input folks.

 

Ryan

[DaV8or]

Quote: rdv

Turn the fuel valve off, brilliant. Simple solution. I like it too! Thanks for all the input folks.

 

Ryan