KR> Help please! High Speed Miss
Brian, Don't know if this will be helpful or not, but is something to check. Under certain circumstances, my KR (gravity feed fuel system) used to either stumble or shut down during high speed passes and would re-fire as soon as the speed bled off. It turned out that the vent for the header tank was in a position such that when I would get the speed up around 175+, I would get a sufficient negative pressure draw on the vent line which would stop the fuel flow to the carb. A minor relocation of the fuel vent to ensure positive pressure at all speeds is all that was necessary to fix the problem. BTW, are you going to get your KR to SWRFI? Weather permitting, mine will be there. -Jeff Scott Los Alamos, NM -- "Brian G. Douglas" wrote: Hi Gang! I was out flying for the first time in 2 months (due to job and WX). When during a fast low aproach at full throttle the engine skipped a beat. Just one beat but it was heard on the ground and I d mn sure felt it. It has done this before and I was thinking that the filter after the Gascolator was just to much for the gravity feed carb. IE running lean, I removed the element and it seemed better. I have the RevMaster 2100, 350 TSN, 15 TSTOH (pistons, head, cylinders, rings, auto spark conversion ) I have the Revflow "carb". I don't know what jet is on it. That is one of my weak areas of knowledge. OK gang any ideas! PS I was thinking aboput just replacing the Revflow with a new one but need to know what size that I need. I have the money but I do like to spend only when I have to. Some times throwing money at a problem works and some times it does not Thanks All! Brian G. Douglas N8575C KR2 Tri Gear Killeen Texas ___ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
KR> Help please! High Speed Miss
Brian, Had to smile a little when you mentioned the engine "skipping a beat". Some of us older KR drivers called it the VW "burp." Everyone I've ever heard experiencing this "heart in the throat" situation was running a suspect Posa carb. I don't think anyone really figured out for sure what was happening, but I think Mark L. is as close as anyone in explaining the phenomenon. Also, I've never heard of a VW actually quitting as a result of it, but I will say that it does cause you concern when you're running along nice and smoothly and all of a sudden - a quick "burp" - then back to normal again. If it were me, I'd change carbs. Wonder if Jim Faughn has ever experienced it? Ed Ed Janssen mailto:ejans...@chipsnet.com - Original Message - From: "Brian G. Douglas" To: "KRnet" Sent: Sunday, May 01, 2005 4:52 PM Subject: KR> Help please! High Speed Miss > Hi Gang! > I was out flying for the first time in 2 months (due to job and WX). When > during a fast low aproach at full throttle the engine skipped a beat. Just > one beat but it was heard on the ground and I d mn sure felt it. It has > done this before and I was thinking that the filter after the Gascolator was > just to much for the gravity feed carb. IE running lean, I removed the > element and it seemed better. > I have the RevMaster 2100, 350 TSN, 15 TSTOH (pistons, head, cylinders, > rings, auto spark conversion ) I have the Revflow "carb". I don't know > what jet is on it. That is one of my weak areas of knowledge. > > OK gang any ideas! > > PS I was thinking aboput just replacing the Revflow with a new one but need > to know what size that I need. I have the money but I do like to spend only > when I have to. Some times throwing money at a problem works and some times > it does not > > Thanks All! > Brian G. Douglas > N8575C > KR2 Tri Gear > Killeen Texas > > > ___ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
KR> Help please! High Speed Miss
Hi Brian, Also check that your tank breather is facing into the slip stream and pressurizing the fuel tank. A fuel flow test on the ground may be different to when flying because of the breather location. regards Barry Kruyssen Cairns, Australia RAA 19-3873 k...@bigpond.com http://www.users.bigpond.com/kr2/kr2.htm - Original Message - From: Brian G. Douglas To: KRnet Sent: Monday, May 02, 2005 7:52 AM Subject: KR> Help please! High Speed Miss Hi Gang! I was out flying for the first time in 2 months (due to job and WX). When during a fast low aproach at full throttle the engine skipped a beat. Just one beat but it was heard on the ground and I d mn sure felt it. It has done this before and I was thinking that the filter after the Gascolator was just to much for the gravity feed carb. IE running lean, I removed the element and it seemed better. I have the RevMaster 2100, 350 TSN, 15 TSTOH (pistons, head, cylinders, rings, auto spark conversion ) I have the Revflow "carb". I don't know what jet is on it. That is one of my weak areas of knowledge. OK gang any ideas! PS I was thinking aboput just replacing the Revflow with a new one but need to know what size that I need. I have the money but I do like to spend only when I have to. Some times throwing money at a problem works and some times it does not Thanks All! Brian G. Douglas N8575C KR2 Tri Gear Killeen Texas ___ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
KR> Help please! High Speed Miss
Hi Scott and all the others! I had thought of that earlier and checked. My vent is next to my venturi on the right side underneath. I checked it for a clog and ran air to see if I could hear it in the tank. Mine is also a gravity feed. I'm going to do the egt test for carb adjustment hat is called out in the revmaster manual. I might be able to get by with just a few turns out on the adjustment needle. (we can always hope ;-) ) SWRFI! I hope to make it. My Scorpion helicopter won "Reserve Champion Rotorcraft" in 2003 not that I think that I will win any thing this time! So many fixed wings so few rotorcraft!! Jeff hope to see you there at HDO any other KR's going? Brian G. Douglas N8575C was a TD Killeen Texas - Original Message - From: "Jeff Scott" To: Sent: Monday, May 02, 2005 10:42 AM Subject: Re: KR> Help please! High Speed Miss > > Brian, > > Don't know if this will be helpful or not, but is something to check. > Under certain circumstances, my KR (gravity feed fuel system) used to > either stumble or shut down during high speed passes and would re-fire as > soon as the speed bled off. It turned out that the vent for the header > tank was in a position such that when I would get the speed up around > 175+, I would get a sufficient negative pressure draw on the vent line > which would stop the fuel flow to the carb. A minor relocation of the > fuel vent to ensure positive pressure at all speeds is all that was > necessary to fix the problem. > > BTW, are you going to get your KR to SWRFI? Weather permitting, mine will > be there. >
KR> Help please! High Speed Miss
Hi Gang! I was out flying for the first time in 2 months (due to job and WX). When during a fast low aproach at full throttle the engine skipped a beat. Just one beat but it was heard on the ground and I d mn sure felt it. It has done this before and I was thinking that the filter after the Gascolator was just to much for the gravity feed carb. IE running lean, I removed the element and it seemed better. I have the RevMaster 2100, 350 TSN, 15 TSTOH (pistons, head, cylinders, rings, auto spark conversion ) I have the Revflow "carb". I don't know what jet is on it. That is one of my weak areas of knowledge. OK gang any ideas! PS I was thinking aboput just replacing the Revflow with a new one but need to know what size that I need. I have the money but I do like to spend only when I have to. Some times throwing money at a problem works and some times it does not Thanks All! Brian G. Douglas N8575C KR2 Tri Gear Killeen Texas
KR> Help please! High Speed Miss
Brian Douglas wrote: > I was out flying for the first time in 2 months (due to job and WX). When > during a fast low aproach at full throttle the engine skipped a beat. Just > one beat but it was heard on the ground and I d mn sure felt it. It has > done this before and I was thinking that the filter after the Gascolator was > just to much for the gravity feed carb. IE running lean, I removed the > element and it seemed better. I don't know diddley about Revflows, but everything you describe so far sounds like insufficient fuel flow. Wide open throttle only, right? Is it gravity feed? If so, I'd do a fuel flow test and make sure you have more than enough (I think the rule is at least 50% more flow than WOT would require). That's a start though. Is it better with a full tank than near empty? That would be another clue. ?That's where I'd start... Mark Langford, Huntsville, Alabama see KR2S project N56ML at http://home.hiwaay.net/~langford email to N56ML "at" hiwaay.net --
KR> Help please! High Speed Miss
Put in an Oxygen sensor and mixture gauge. That will take out a lot of the guess work. Brian Kraut Engineering Alternatives, Inc. www.engalt.com -Original Message- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net]On Behalf Of Brian G. Douglas Sent: Sunday, May 01, 2005 5:53 PM To: KRnet Subject: KR> Help please! High Speed Miss Hi Gang! I was out flying for the first time in 2 months (due to job and WX). When during a fast low aproach at full throttle the engine skipped a beat. Just one beat but it was heard on the ground and I d mn sure felt it. It has done this before and I was thinking that the filter after the Gascolator was just to much for the gravity feed carb. IE running lean, I removed the element and it seemed better. I have the RevMaster 2100, 350 TSN, 15 TSTOH (pistons, head, cylinders, rings, auto spark conversion ) I have the Revflow "carb". I don't know what jet is on it. That is one of my weak areas of knowledge. OK gang any ideas! PS I was thinking aboput just replacing the Revflow with a new one but need to know what size that I need. I have the money but I do like to spend only when I have to. Some times throwing money at a problem works and some times it does not Thanks All! Brian G. Douglas N8575C KR2 Tri Gear Killeen Texas ___ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
