---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Mon 01/12/09: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:05 PM - 3300A - Full Throttle Roughness (Don Honabach) 2. 10:23 PM - Re: 3300A - Full Throttle Roughness (Peter Harris) 3. 10:35 PM - 3300A - Full Throttle Roughness (Don Honabach) 4. 10:58 PM - Re: 3300A - Full Throttle Roughness (Don Honabach) 5. 11:12 PM - Re: 3300A - Full Throttle Roughness (Peter Harris) ________________________________ Message 1 _____________________________________ Time: 10:05:57 PM PST US Subject: JabiruEngine-List: 3300A - Full Throttle Roughness From: "Don Honabach" I'm having an issue where during cruise flight if I go full throttle either in straight and level or climb, the engine gets rough enough that it feels like it will quit. At this point, I obviously don't want to push the issue so I pull back on the throttle until the roughness goes away. Interestingly, I have no problem with full throttle roughness on take-off/climb-out. I also did some additional testing today and found that if I ease real slow into full throttle from cruise that I still get the roughness but not as bad and that the RPM will increase up to ~2,9xx and then start to degrade as I continue to add power along with additional roughness. Background info: Full Throttle Static RPM/Ground Run Up is ~2,800RPM. No issues with roughness. On my 601HDS, I have a 3300A with the Sensenich Carbon Prop (64"? 2A0J5R64Z-N) that was purchased from Jabiru USA/Pete K. back in 2006. Any help greatly appreciated. I've sent this same question to Jabiru USA and haven't gotten a response yet (sent last Thursday and sent another today asking for status). Initially thought it was the SCAT intake hose which I replaced with the rubber 90 degree elbow. Same issue with either intake method. Thanks! Don Honabach Tempe, AZ ________________________________ Message 2 _____________________________________ Time: 10:23:36 PM PST US From: "Peter Harris" Subject: RE: JabiruEngine-List: 3300A - Full Throttle Roughness It sounds like it may be too rich under the load conditions at WOT cruise. The fuel bowl is fitted with 2.25mm needle valve seat which is meant for gravity feed, but they have selected the power needle as a compromise. If you are using a fuel pump it may cause the needle valve seat to leak and overfill the fuel bowl causing excessive rich mixture near max rpm. Another cause of over rich mixture is due to the starting choke not fully closing due to friction in the cable. Peter _____ From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Don Honabach Sent: Tuesday, 13 January 2009 4:03 PM Subject: JabiruEngine-List: 3300A - Full Throttle Roughness I'm having an issue where during cruise flight if I go full throttle either in straight and level or climb, the engine gets rough enough that it feels like it will quit. At this point, I obviously don't want to push the issue so I pull back on the throttle until the roughness goes away. Interestingly, I have no problem with full throttle roughness on take-off/climb-out. I also did some additional testing today and found that if I ease real slow into full throttle from cruise that I still get the roughness but not as bad and that the RPM will increase up to ~2,9xx and then start to degrade as I continue to add power along with additional roughness. Background info: Full Throttle Static RPM/Ground Run Up is ~2,800RPM. No issues with roughness. On my 601HDS, I have a 3300A with the Sensenich Carbon Prop (64"? 2A0J5R64Z-N) that was purchased from Jabiru USA/Pete K. back in 2006. Any help greatly appreciated. I've sent this same question to Jabiru USA and haven't gotten a response yet (sent last Thursday and sent another today asking for status). Initially thought it was the SCAT intake hose which I replaced with the rubber 90 degree elbow. Same issue with either intake method. Thanks! Don Honabach Tempe, AZ ________________________________ Message 3 _____________________________________ Time: 10:35:13 PM PST US Subject: JabiruEngine-List: 3300A - Full Throttle Roughness From: "Don Honabach" I'm having an issue where during cruise flight if I go full throttle either in straight and level or climb, the engine gets rough enough that it feels like it will quit. At this point, I obviously don't want to push the issue so I pull back on the throttle until the roughness goes away. Interestingly, I have no problem with full throttle roughness on take-off/climb-out. I also did some additional testing today and found that if I ease real slow into full throttle from cruise that I still get the roughness but not as bad and that the RPM will increase up to ~2,9xx and then start to degrade as I continue to add power along with additional roughness. Background info: Full Throttle Static RPM/Ground Run Up is ~2,800RPM. No issues with roughness. On my 601HDS, I have a 3300A with the Sensenich Carbon Prop (64"? 2A0J5R64Z-N) that was purchased from Jabiru USA/Pete K. back in 2006. Any help greatly appreciated. I've sent this same question to Jabiru USA and haven't gotten a response yet (sent last Thursday and sent another today asking for status). Initially thought it was the SCAT intake hose which I replaced with the rubber 90 degree elbow. Same issue with either intake method. Thanks! Don Honabach Tempe, AZ ________________________________ Message 4 _____________________________________ Time: 10:58:16 PM PST US Subject: RE: JabiruEngine-List: 3300A - Full Throttle Roughness From: "Don Honabach" Peter, Thanks for the quick reply. FYI, I have a low-wing design and during take-off I use an electric boost pump but during transition to cruise I turn it off and just use the engine driven mechanical fuel pump on the 3300A. Even with the boost pump, I don't exceed 3PSI (at least as much as I can trust the accuracy of the gauge at such low values and a narrow range). Assuming the needle leaking is the issue, is there a fix for non-gravity feed setups? As a side question, do those with gravity setups remove the engine driven pump? I'm assuming that if I turn on the boost pump during cruise and if I have a needle leak issue that the problem should be noticeable sooner or should be worse as the increased pressure will cause more leakage? I'll check the choke cable as well to make sure it is fully closing. Thanks! Don From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Peter Harris Sent: Monday, January 12, 2009 23:21 Subject: RE: JabiruEngine-List: 3300A - Full Throttle Roughness It sounds like it may be too rich under the load conditions at WOT cruise. The fuel bowl is fitted with 2.25mm needle valve seat which is meant for gravity feed, but they have selected the power needle as a compromise. If you are using a fuel pump it may cause the needle valve seat to leak and overfill the fuel bowl causing excessive rich mixture near max rpm. Another cause of over rich mixture is due to the starting choke not fully closing due to friction in the cable. Peter ________________________________ From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Don Honabach Sent: Tuesday, 13 January 2009 4:03 PM Subject: JabiruEngine-List: 3300A - Full Throttle Roughness I'm having an issue where during cruise flight if I go full throttle either in straight and level or climb, the engine gets rough enough that it feels like it will quit. At this point, I obviously don't want to push the issue so I pull back on the throttle until the roughness goes away. Interestingly, I have no problem with full throttle roughness on take-off/climb-out. I also did some additional testing today and found that if I ease real slow into full throttle from cruise that I still get the roughness but not as bad and that the RPM will increase up to ~2,9xx and then start to degrade as I continue to add power along with additional roughness. Background info: Full Throttle Static RPM/Ground Run Up is ~2,800RPM. No issues with roughness. On my 601HDS, I have a 3300A with the Sensenich Carbon Prop (64"? 2A0J5R64Z-N) that was purchased from Jabiru USA/Pete K. back in 2006. Any help greatly appreciated. I've sent this same question to Jabiru USA and haven't gotten a response yet (sent last Thursday and sent another today asking for status). Initially thought it was the SCAT intake hose which I replaced with the rubber 90 degree elbow. Same issue with either intake method. Thanks! Don Honabach Tempe, AZ http://www.matronics.com/Navigator?JabiruEngine-List http://forums.matronics.com http://www.matronics.com/contribution Checked by AVG - http://www.avg.com 1/12/2009 07:04 ________________________________ Message 5 _____________________________________ Time: 11:12:41 PM PST US From: "Peter Harris" Subject: RE: JabiruEngine-List: 3300A - Full Throttle Roughness Don I have the J3300 in a Quickie Q-200 and getting 170KTS at 3000 ft CAS but still not happy with the higher power settings and feel it has more potential. Yes you could try the boost pump and that would indicate if there is a problem with the needle valve seat. It is possible to almost stop the engine if it gets too rich even at WOT. The setup is supposed to be OK at 3PSI. Some have fitted a fuel pressure regulator but if you are sure you have 3PSI up to WOT I don't see any value in adding another fail point. Maybe it is the choke. The return spring is not very strong. Peter _____ From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Don Honabach Sent: Tuesday, 13 January 2009 4:55 PM Subject: RE: JabiruEngine-List: 3300A - Full Throttle Roughness Peter, Thanks for the quick reply. FYI, I have a low-wing design and during take-off I use an electric boost pump but during transition to cruise I turn it off and just use the engine driven mechanical fuel pump on the 3300A. Even with the boost pump, I don't exceed 3PSI (at least as much as I can trust the accuracy of the gauge at such low values and a narrow range). Assuming the needle leaking is the issue, is there a fix for non-gravity feed setups? As a side question, do those with gravity setups remove the engine driven pump? I'm assuming that if I turn on the boost pump during cruise and if I have a needle leak issue that the problem should be noticeable sooner or should be worse as the increased pressure will cause more leakage? I'll check the choke cable as well to make sure it is fully closing. Thanks! Don From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Peter Harris Sent: Monday, January 12, 2009 23:21 Subject: RE: JabiruEngine-List: 3300A - Full Throttle Roughness It sounds like it may be too rich under the load conditions at WOT cruise. The fuel bowl is fitted with 2.25mm needle valve seat which is meant for gravity feed, but they have selected the power needle as a compromise. If you are using a fuel pump it may cause the needle valve seat to leak and overfill the fuel bowl causing excessive rich mixture near max rpm. Another cause of over rich mixture is due to the starting choke not fully closing due to friction in the cable. Peter _____ From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Don Honabach Sent: Tuesday, 13 January 2009 4:03 PM Subject: JabiruEngine-List: 3300A - Full Throttle Roughness I'm having an issue where during cruise flight if I go full throttle either in straight and level or climb, the engine gets rough enough that it feels like it will quit. At this point, I obviously don't want to push the issue so I pull back on the throttle until the roughness goes away. Interestingly, I have no problem with full throttle roughness on take-off/climb-out. I also did some additional testing today and found that if I ease real slow into full throttle from cruise that I still get the roughness but not as bad and that the RPM will increase up to ~2,9xx and then start to degrade as I continue to add power along with additional roughness. Background info: Full Throttle Static RPM/Ground Run Up is ~2,800RPM. No issues with roughness. On my 601HDS, I have a 3300A with the Sensenich Carbon Prop (64"? 2A0J5R64Z-N) that was purchased from Jabiru USA/Pete K. back in 2006. Any help greatly appreciated. I've sent this same question to Jabiru USA and haven't gotten a response yet (sent last Thursday and sent another today asking for status). Initially thought it was the SCAT intake hose which I replaced with the rubber 90 degree elbow. Same issue with either intake method. Thanks! Don Honabach Tempe, AZ http://www.matronics.com/Navigator?JabiruEngine-List http://forums.matronics.com http://www.matronics.com/contribution &nbssp; - The JabiruEngine-List Email Forum utilities such as List Photoshare, and much much --> http://www.matronics.com/Navigator?JabiruEngine-List http://forums.matronics.com - List Contribution Web generous nbsp; --> http://www.matronics.com/c= No virus found in this incoming message. 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