---------------------------------------------------------- TeamGrumman-List Digest Archive --- Total Messages Posted Sat 01/22/11: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:00 PM - Fw: engine advice needed (GOLDPILOT@AOL.COM) 2. 05:45 PM - Re: Fw: engine advice needed (Andy) 3. 05:53 PM - Re: Fw: engine advice needed (Linn Walters) ________________________________ Message 1 _____________________________________ Time: 05:00:41 PM PST US From: GOLDPILOT@AOL.COM Subject: TeamGrumman-List: Fwd: engine advice needed ____________________________________ From: david@newlangsyne.com Sent: 1/22/2011 5:27:23 A.M. Pacific Standard Time Subj: engine advice needed Would you be kind enough to forward this to the Grumman Gang? The guy who needs the information will be able to see it. Thanks. -------------------------------------------------------------- I'm looking for advice about two engines. Tiger #1: 1979 AA-5B Lyc O-360-A4K (carbureted) Tiger #2: 1991 AG-5B Lyc O-360-A4K (carbureted) Each has developed the same problem, about 30 hours after being overhauled. If the throttle is advanced rapidly, the engine sometimes (not always) stumbles, almost dies, and THEN responds. Sounds like a problem with the accelerator pump, doesn't it? But... Ops normal for the first several hours after overhaul, which used new cylinders and included new intake manifolds. Tiger #1 has had two new (overhauled) carbs since the problem appeared, same problem. Tiger #2 has had FOUR carbs since the problem appeared, same problem. three fresh overhauled one was the carburetor that was working fine on Tiger #1 just before its engine went in for overhaul We (two flying clubs) have been using the same engine shop for at least a dozen engines over the past 15 years or more. We've followed his recommended break-in procedures with each engine. The only difference is that he recommended Phillips 20W50 to break in Tiger #1 (most recent overhaul), where we always used Shell mineral oil before. I think Philips 20W50 oil was used for Tiger #2 also, but I'm not sure. The owner has - swapped carburetors as already described - checked carb heat boxes - isolated primer lines Any ideas? I'm looking for something that - mimics a bad accelerator pump but is something else - didn't start until about 30 hours after engine overhaul Thanks for your collective wisdom. This one is very frustrating. ________________________________ Message 2 _____________________________________ Time: 05:45:00 PM PST US From: "Andy" Subject: Re: TeamGrumman-List: Fwd: engine advice needed Are the symptoms the same with the boost pump on ? ----- Original Message ----- From: GOLDPILOT@AOL.COM To: teamgrumman-list@matronics.com Sent: Saturday, January 22, 2011 6:57 PM Subject: TeamGrumman-List: Fwd: engine advice needed ------------------------------------------------------------------------- --- From: david@newlangsyne.com To: goldpilot@aol.com Sent: 1/22/2011 5:27:23 A.M. Pacific Standard Time Subj: engine advice needed Would you be kind enough to forward this to the Grumman Gang? The guy who needs the information will be able to see it. Thanks. -------------------------------------------------------------- I'm looking for advice about two engines. Tiger #1: 1979 AA-5B Lyc O-360-A4K (carbureted) Tiger #2: 1991 AG-5B Lyc O-360-A4K (carbureted) Each has developed the same problem, about 30 hours after being overhauled. If the throttle is advanced rapidly, the engine sometimes (not always) stumbles, almost dies, and THEN responds. Sounds like a problem with the accelerator pump, doesn't it? But... Ops normal for the first several hours after overhaul, which used new cylinders and included new intake manifolds. Tiger #1 has had two new (overhauled) carbs since the problem appeared, same problem. Tiger #2 has had FOUR carbs since the problem appeared, same problem. three fresh overhauled one was the carburetor that was working fine on Tiger #1 just before its engine went in for overhaul We (two flying clubs) have been using the same engine shop for at least a dozen engines over the past 15 years or more. We've followed his recommended break-in procedures with each engine. The only difference is that he recommended Phillips 20W50 to break in Tiger #1 (most recent overhaul), where we always used Shell mineral oil before. I think Philips 20W50 oil was used for Tiger #2 also, but I'm not sure. The owner has - swapped carburetors as already described - checked carb heat boxes - isolated primer lines Any ideas? I'm looking for something that - mimics a bad accelerator pump but is something else - didn't start until about 30 hours after engine overhaul Thanks for your collective wisdom. This one is very frustrating. ________________________________ Message 3 _____________________________________ Time: 05:53:51 PM PST US From: Linn Walters Subject: Re: TeamGrumman-List: Fwd: engine advice needed I go with the accelerator pump too. Take the carbs off and hook up a temporary fuel source. Exercise the accelerator pump and look at the fuel expended in the throat. I'm guessing you'll find a poor amount of fuel. Take the carbs apart yourselves and clean out the passage from the pump to the throat. I'd also make sure that pump really belongs in that carb ....... should be obvious. I doubt the rebuilders catch either one, making the same mistake each time. Linn On 1/22/2011 7:57 PM, GOLDPILOT@AOL.COM wrote: > > ------------------------------------------------------------------------ > From: david@newlangsyne.com > To: goldpilot@aol.com > Sent: 1/22/2011 5:27:23 A.M. Pacific Standard Time > Subj: engine advice needed > Would you be kind enough to forward this to the Grumman Gang? > The guy who needs the information will be able to see it. > Thanks. > > -------------------------------------------------------------- > > I'm looking for advice about two engines. > > Tiger #1: 1979 AA-5B Lyc O-360-A4K (carbureted) > Tiger #2: 1991 AG-5B Lyc O-360-A4K (carbureted) > > Each has developed the same problem, about 30 hours after being > overhauled. > > If the throttle is advanced rapidly, the engine sometimes (not always) > stumbles, almost dies, and THEN responds. Sounds like a problem > with the > accelerator pump, doesn't it? > > But... > > Ops normal for the first several hours after overhaul, which used new > cylinders and included new intake manifolds. > > Tiger #1 has had two new (overhauled) carbs since the problem > appeared, same problem. > Tiger #2 has had FOUR carbs since the problem appeared, same problem. > three fresh overhauled > one was the carburetor that was working fine on Tiger #1 just > before > its engine went in for overhaul > > We (two flying clubs) have been using the same engine shop for at > least a > dozen engines over the past 15 years or more. We've followed his > recommended > break-in procedures with each engine. The only difference is that he > recommended Phillips 20W50 to break in Tiger #1 (most recent > overhaul), where > we always used Shell mineral oil before. I think Philips 20W50 > oil was used > for Tiger #2 also, but I'm not sure. > > The owner has > - swapped carburetors as already described > - checked carb heat boxes > - isolated primer lines > > Any ideas? I'm looking for something that > - mimics a bad accelerator pump but is something else > - didn't start until about 30 hours after engine overhaul > > Thanks for your collective wisdom. This one is very frustrating. > > * > > > * ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message teamgrumman-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/TeamGrumman-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/teamgrumman-list Browse Digests http://www.matronics.com/digest/teamgrumman-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.