persof 14 #1 Posted February 24, 2011 My C-161a frequently backfires when I shut it off. Any ideas on how to correct this? A modest leaning of the low speed needle on my 312-8 correcrted it's backfiring but if I do that on the C-161a it will not transition up to full RPM??? Thanks Francis Share this post Link to post Share on other sites
MikesRJ 552 #2 Posted February 24, 2011 I'm no expert, but here goes ... Backfiring is normally caused by a fuel issue or a timing issue. Assuming the engine is mechanically sound (the assumption here is referring to a valve or other internal mechanical issue) and there are no mechanical issues, check the following: Engine Timing: See this process - http://www.mywheelhorse.com/graphics/file/...ngineTiming.pdf Fuel System: Check the fuel filter, check the fuel pump, check the fuel lines, check any fuel shut-off valves, and/or clean the carburetor - http://www.mywheelhorse.com/graphics/file/...etorRebuild.pdf Share this post Link to post Share on other sites
JimD 3,345 #3 Posted February 24, 2011 Sometimes the backfire is caused by glowing rusty embers in the muffler igniting unburned fuel from the engine idling down. Some suggest shutting it off at full throttle. I disagree with this. I always idle down and let the engine run for a minute at idle before shutting it off. This works for my tractors, might for yours too. :thumbs: Share this post Link to post Share on other sites
mavfreak 11 #4 Posted February 25, 2011 Is this a Briggs twin? Share this post Link to post Share on other sites
JC 1965 1,528 #5 Posted February 25, 2011 I don't know if it has anything to do with your problem but I agree with Jim. I always idle mine down before turning them off. Just my 2 cents worth!! :thumbs: Share this post Link to post Share on other sites
persof 14 #6 Posted February 25, 2011 I do allow idle time before shut down and it had a new muffler. It is a 16HP Kholer and I have not had a chance to check the timing (dave a dewll meter but no timing light) Thanks Francis Share this post Link to post Share on other sites