First of all, thank to everyone that has offered suggestions.
A lot of people have remarked that it may be carb ice. I don't think it is because I get an RPM increase even sittting on the ground at full throttle when I pull the carb heat half on. This is in Florida in 85 degree temperatures and relatively low humidity for this area. The engine also immediately picks up RPM when the heat is pulled and immediately looses it when it is pushed back in. Now maybe there is some problem with this carb not atomizing the fuel well unless it is heated a little. If that is the case I would suspect that someone else would have seen this problem in the past. I do plan on ordering an EGT to be sure the mixture is correct and see if it changes when the carb heat is pulled. I will probably also order a mixture indicator from [1]http://www.halmeter.com/. This uses an O2 sensor in the exhaust. I also will be adding a MAP gauge and may even try a temporary Radio Shack temp probe in the carb while on the ground to see what kind of temps I have. -----Original Message----- From: Harold Woods Sent: Oct 21, 2003 4:31 PM To: Brian Kraut Subject: rough engine. Hi Brian Sounds to me like a classic case of carb ice. It may be Florida and 85F on the ground which gives you a high humidity. Go up to 8500 feet and the temperature is much lower but the air still has the same weight of water vapour in it. As it is pulled through the carb the temperature falls further, the water condences and freezes. You get carb ice. Add enough hot air to melt it and keep it from reforming, adjust the mixture to suit and you have solved the problem. Regards Harold Woods Orillia,ON.Can. [2]haroldwo...@rogers.com --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system ([3]http://www.grisoft.com). Version: 6.0.522 / Virus Database: 320 - Release Date: 9/29/2003 References 1. http://www.halmeter.com/ 2. mailto:haroldwo...@rogers.com 3. http://www.grisoft.com/
