---------------------------------------------------------- Lom-List Digest Archive --- Total Messages Posted Sun 09/06/20: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:28 PM - Re: Fuel Mixture () ________________________________ Message 1 _____________________________________ Time: 04:28:29 PM PST US From: Subject: RE: Lom-List: Fuel Mixture Hello I have been away for a while but back now. I drained the sump on the Cam Cover and there was about a cup of oil. There is a large plug on the side of the fuel pump and I assumed that this is the level the oil is supposed to be that is mentioned in the manual. I filled the fuel pump to this level and it took about =C2=BC cup or +/- 60ml When I tried to start the engine there is now nothing, not even a =9C poof=9D or even one firing on the primer fuel. I tested for spark an d that seems to be OK, and I can hear the Slickstart buzzing when I power i t up I removed all the plugs and fuel injector nozzles, I fitted a nut to one of the nozzles and rotated the prop by hand, I got one squirt of gas out of t he nozzle but after that I only saw drops forming at the tip of the nozzle. Is the return oil line that runs from the fuel pump to the sump equipped wi th a one way valve? I thought of running oil into the fuel pump and then ch ecking if oil runs out of the sump plug cam case plug. Not sure if there is a direct connection, but there must be something that stops the cam case o il draining into the fuel pump. The deposits at the rear of the exhaust manifold is darkish gray Would appreciate you suggestions. Thanks Mike From: owner-lom-list-server@matronics.com On Behalf Of sjbeaver Sent: August 24, 2020 5:08 AM Subject: Re: Lom-List: Fuel Mixture That is a surprising amount of oil. In a normally functioning, current revi sion engine I would expect to see perhaps a table spoon of oil. In the olde r style pump with a filler port on the side, perhaps a cup. Then again I ha ve never left the pump open overnight. There is a connection from the engin e oil system to the pump in that one of the factors the pump uses to set th e fuel mixture is oil pressure. I would suggest proceeding as follows: 1. Remove the drain plug/screen under the scavenge pump. How muc h oil do you see there? If you see a a cup or more then I would suggest all is well. If you see almost none then it would appear that the cam case oil is somehow leaking into the injection pump. This seems unlikely though 2. Put everything back together and run the engine. Asses the pe rformance per my previous email and then remove the oil drain plug in the p ump again. How much oil this time? (Use something more scientific than the hangar floor to measure it :) ) Steve -- Stephen Beaver Tel: 614-937 4189 On Aug 24, 2020, at 12:04 AM, > > wrote: Hello Steve I also thought it was impossible, I drained it from a small plug at the bot tom of the fuel pump, the plug only needs a 12mm wrench so is small. Workin g forward from the rear of the pump there is a small slotted screw and then the plug. These are the only fittings on the bottom of the fuel pump. I ca n see a large nut on the camshaft cover that I assumed to be the drain unde r the scavenge pump, I did not open that. Could this oil have siphoned from somewhere? Thanks for you help Mike From: owner-lom-list-server@matronics.com > On Behalf Of sjbeaver Sent: August 23, 2020 7:57 PM Subject: Re: Lom-List: Fuel Mixture Three pints seems impossible. Did you drain that from the pump, or from the screen at the rear of the camshaft housing? Steve -- Stephen Beaver Tel: 614-937 4189 On Aug 23, 2020, at 10:33 PM, > > wrote: Hello Steve, I drained the oil from the fuel pump. I removed the plug and oil came out v ery slowly so I left it overnight. Fortunately I put a small container unde r the drain hole as this morning I found that about 3 pints had drained out =2E I cannot imagine where there is room for that amount of oil. Could it be th at my scavenge pump is not doing it=99s job? Have not tried to start it again but will let you know Thanks Mike From: owner-lom-list-server@m atronics.com < owner-lom-list- server@matronics.com> On Behalf Of sjbeaver Sent: August 18, 2020 10:00 AM nics.com> Subject: Re: Lom-List: Fuel Mixture Mike. There are no o-rings in the fuel inject system to be concerned about and I would suggest that you do not disassemble it. It is a complex and very prec ise device! - What you might do, however, is remove the drain plug on the u nderside of the unit and allow any accumulated oil to drain out. If sitting for a long time excess oil can accumulate in the pump and interfere with t he mixture. Let me run through some of the other items you might check. I am not implyi ng that there is any part of the manual you have not digested. Just making sure I don't omit anything :) First and foremost (If I had a $ for every time I explain this . . . ) is the automatic mixture system. People used to operating American engines see m to think that the engine should always be operated at the most rich setti ng available. That is just not the case with the LOM and doing so so will h ave serval rather bad consequences. Look closely at the mixture control arm that extends from the side of the f uel injection pump. There is a slot in the arm, inside of which is a small pointer. Also on the side of the pump is a shiny metal plate shaped like a pizza slice on which are marked the mixture settings. Something like +3, +2 , +1, N, -1, -2 with the -2 being nearest the top. Adjust your mixture cont rol mechanism so that the "normal" (all phases of operation below 10,000') corresponds to the pointer being aligned with the 'N' mark. - Actually 'N' inside a circle. Now you know the mixture is set exactly as it should be. A gain - do not operate the engine at the full rich setting. Doing so will di sable the automatic mixture system, foul the plugs, wash lubricant from the cylinder walls and other bad things. Next, start the engine and let it warm up for an extended period. When the oil temp is up in the 100F area, carefully and with the appropriate precaut ions run the engine at full power (super charger engaged) Switch from both to magneto 1. What RPM drop do you see? Go back to both, then magneto 2. Ag ain, what RPM drop do you see? I would expect a drop in the 25-35 RPM area. Anything other than that suggests your ignition timing is a little out. It is a simple matter to loosen the magneto clamps and rotate the mags a litt le until the 25-35 RPM drop is observed. Why not just time the mags with a buzz box in the traditional manner? For two reasons: 1) This is how the man ual says to do it and 2) these magnetos have automatic advance and retard s ystems so static timing means almost nothing. How that the mixture and the ignition timing are up to snuff, you can do so me testing. Operate the engine for as long as is reasonable at a cruise sor t of power setting. Say 25" of manifold pressure. (It doesn't matter if the super charger is engaged or not). Now shut down and observe the exhaust pi pes. Are they back and sooty, a very light gray (almost white) or a nice mi d gray, the color of a slate roof? - We want the slate color. If in doubt, remove the spark plugs and see what they look like. Another useful trick (if you have straight pipes) is to run the engine in t he dark and look into the exhaust pipes of the running engine. At medium po wer settings look for a nice blue flame tinged with yellow to indicate the ideal running conditions. Finally, since I see you are in BC, you could contact Pavol Novak who now r esides at Qualcom Beach on Victoria Island. He is a Czech LOM factory train ed technician and expert on the engines (and Zlin airframes) Steve -- Stephen Beaver Tel: 614-937 4189 On Aug 18, 2020, at 12:14 PM, > > wrote: I have the 4 cylinder engine with supercharger, fuel injection and automati c mixture control. The motor was factory reconditioned in 2003 and has had Zero hours since I started the motor recently and there are loud =9Cpops=9D out of the exhaust. An AME on the field thought that it was running lean. Fuel pressure is good I see that I can adjust the mixture at the fuel pump but want to ask if the re is something else I should check for first. Has anybody opened the fuel pump, are there any seals that would have deter iorated. From the drawing I cannot see if there are any seals that may need replacing. Thanks Mike Mike Pienaar m ike@vision499.com Home: +1 250-999-8121 Mike cell: +1 250-885-0554 1-1100 Tulip Ave, Victoria, BC, V8Z 0A2 Virus-free. www.avast.com -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message lom-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Lom-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/lom-list Browse Digests http://www.matronics.com/digest/lom-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.