coppercity Posted May 28, 2012 Report Share Posted May 28, 2012 A couple days ago during a training flight with a student we experienced a rough running engine while at lower power settings. We set the throttle to a position where the engine ran smoothly and returned for an uneventful landing. Looking at the indications on the EMS during the event the RIght side EGT would drop off significantly to 600-700 deg vs a 1000 on the left. My first thought was maybe a throttle cable had slipped. After opening the cowling though and inspecting the cables and throttle arms everything looked normal. Next place to look was the float bowls. I pulled the right side first since it seemed abnormal according to the EMS. Sure enough one of the floats was sunk to the bottom of the bowl! As long as the engine was at a higher power setting needing more fuel everything was fine, but as the fuel requirements went down with lower power settings and the float bowl overfilled then the engine ran rough. Replaced all the floats and everything runs like a champ again. Link to comment Share on other sites More sharing options...
Runtoeat Posted May 28, 2012 Report Share Posted May 28, 2012 Hi Eric. What was the issue with the float? Are there newer materials used for the new floats that may be more durable or less prone to absorbing fuel or leaking compared to older ones? Link to comment Share on other sites More sharing options...
Roger Lee Posted May 29, 2012 Report Share Posted May 29, 2012 Hi Dick, There is nothing you can do. Once in a great while a float looses it's integrity and absorbs some fuel and sinks. It may sink only part way or to the bottom of the bowl. The result will be rough running. Your only recourse is to buy a new set of floats. They come in pairs. They are a little over $100. Link to comment Share on other sites More sharing options...
Runtoeat Posted May 29, 2012 Report Share Posted May 29, 2012 Hi Roger. Thanks. Right now, it ain't broke so I ain't fixin'! Hope I don't jinx myself by saying this! Link to comment Share on other sites More sharing options...
Roger Lee Posted May 29, 2012 Report Share Posted May 29, 2012 The way to tell if you have a defective float is to pull the bowl. leave the floats in and fill the bowl up to about 1/4" from the top edge with fuel. The pins on the floats should be equal to the fuel level. If a pin is down under the fuel level a ways it is going bad. Link to comment Share on other sites More sharing options...
coppercity Posted May 29, 2012 Author Report Share Posted May 29, 2012 In hindsight, the spark plugs on the side with the bad float had been a little darker in color at the previous 100hr, which was about 20 hrs before the failure, that may have been a sign as well. Certainly the check Roger recommends is a good method. Link to comment Share on other sites More sharing options...
Runtoeat Posted May 29, 2012 Report Share Posted May 29, 2012 Roger and Eric, as I understand your troubleshooting technique, you hold the float bowl in your hand with the float in it and add fuel to about 1/4" from the top of the bowl. If the float pin doesn't stay up with the top of the fuel, the floats (must replace both) need replacement. Correct? Link to comment Share on other sites More sharing options...
Roger Lee Posted May 29, 2012 Report Share Posted May 29, 2012 correct. The float pins should be even with the fuel. Link to comment Share on other sites More sharing options...
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