evolution engine wont stop running
 

I recently tried to help two different new club members with the engines on their planes. They both had .46 evolution engines. The carbs were tightened snug in the engines and I couldnt find any air leaks. Neither engine would stop running with the inlet on the carbs completely closed. I even covered the openings with a finger and they just continued to idle along. What the heck is going on here? I felt like a newbie trying to help them. Has anyone seen this before?

RE: evolution engine wont stop running
 

It's got to be getting air from some place.

RE: evolution engine wont stop running
 

Perhaps more info would help. What do they do when you increase throttle quickly to wide open? what happens if you use the pinch test? What is the idle speed? How do they run when wide open or through out the range?I know those carbs have limitors on them, take them off. I have 2 and they run great.

RE: evolution engine wont stop running
 

Yes and not just on the Es. I started leak seeking just like you do when checking for leaks on a gas water heater. I use soapy water and a length of fuel line on the carb nipple. Slather the soapy water all around te carb and the case, open the carb and stick a finger over it then blow hard on the line. When you see the bubbles you know where the leak is.
One of my SK .91 wouldn't quit running at all unless I pulled the fuel line. I got home and did the soap thing and found air bubbles at the steel insert that is press fit into the case for the carb hold down screw. The Fix: cleaned the area around the case and inset with acetone, mixed up some JB weld, heated it up to thin it then squished it with pressure around the leaking area and wiped off the excess. Problem solved.
When it got hot the case was expanding more then the steel and over time wasn't seating tight enough and causing an air leak.
There you are, my trick for the day!!:D

RE: evolution engine wont stop running
 

I had an Irvine that did the same thing. My culprit was a damaged oring on the carburator letting air into the intake. New oring fixed it right up.

RE: evolution engine wont stop running
 

Yep, turned, twister or torn O-ring or a loose carb are the main problems found. The soap test shows that right away and is an easy fix.

RE: evolution engine wont stop running
 

The engine idles around 2800 rpm. I winds right up when you go full throttle. Turns 11500 rpm peak on the ground with an 11" prop. Don't know the pitch. Thanks for the help.

RE: evolution engine wont stop running
 

My Irvine ran really well with an oring leak. And there was no dicernable different after the fix besides being able to kill the engine on the transmitter finally.