---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Tue 06/29/10: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:09 AM - Re: Re: Tach reads perfect until 4k, then goes to 7k?? (Brian Davies) 2. 01:18 AM - Re: Re: Tach reads perfect until 4k, then goes to 7k?? (GRAHAM SINGLETON) 3. 03:41 AM - 914 Fuel Pump (h&jeuropa) 4. 08:34 AM - Re: Tach reads perfect until 4k, then goes to 7k?? (ricklach) ________________________________ Message 1 _____________________________________ Time: 01:09:08 AM PST US From: "Brian Davies" Subject: RE: RotaxEngines-List: Re: Tach reads perfect until 4k, then goes to 7k?? Hi Rick, Sorry about the vague reply I gave. I was away from my office so could not get to the reference. I have attached a file from Rotax Owner Assistance Network (ROAN) which gives the guidance. It suggests using a 200 ohm resistor across the trigger coil on the stator. I have had just as much success using a resistor across the equivalent terminals on the back of the Tach. On the Rotax tach it goes across terminals 2 and 3. I have also cured this problem by swapping over the blue and white wires in the connecting plug. In some cases the only cure was changing the tacho. You will see from all of this that there is something a bit marginal about the Rotax 912 tacho set up. The pick up seems to produce a relatively low voltage (3v) strangely shaped pulse when properly loaded but can give out as much as 100volts if not properly loaded. That is why the 200 ohm resistor sometimes fixes the problem. By the way, the trigger coil produces 1 pulse per revolution. I have never had a problem with the UMA replacement for the "official" Rotax Tach. Regards Brian -----Original Message----- From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of ricklach Sent: 28 June 2010 22:49 Subject: RotaxEngines-List: Re: Tach reads perfect until 4k, then goes to 7k?? --> Carl and Brian, I=C3=A2=82=AC=84=A2ve been working with the same problem as Carl. My Rotax rev-counter is solid until it reaches 4800-5000 then it goes to 7000, like Carl=C3=A2=82=AC=84=A2s. I=C3=A2=82=AC=84=A2ve been searching through all the SB=C3=A2=82=AC=84=A2s, SI=C3=A2=82=AC=84=A2s, SA=C3=A2=82=AC=84=A2s and SL=C3=A2=82=AC=84=A2s and I only found Service Instruction =C3=A2=82=AC=C5=93SI-13-1996 R2=C3=A2=82=AC=C2=9D that refers to installing a tack. But I find no reference to a resister across any terminals in this document. Have I missed it or is there another document you=C3=A2=82=AC=84=A2re referring to? Also Brian what two terminals are you putting the resister across? Service Instruction =C3=A2=82=AC=C5=93SI-13-1996 R2=C3=A2=82=AC=C2=9D has six installation configurations. I=C3=A2=82=AC=84=A2m like most people Fig. 3 is my installation, the simple one. All other =C3=A2=82=AC=C5=93FIG=C3=A2=82=AC=C2=9D are for a Rotax Fly-Dat or a 914 with a TCU. After review all the Schematics in the 912 Installation Manual and the Heavy Maintenance Manual all schematics showed a simple direct connection, without a ground, between the tack #2 =C3=A2=82=AC=C5=93-=C3=A2=82=AC=C5=93 terminal and the rev pick up. I tried that and the tack did not work at all. I then replaced the ground between the tack #2 =C3=A2=82=AC=C5=93-=C3=A2=82=AC=C5=93 terminal as shown in Fig. 3 of =C3=A2=82=AC=C5=93SI-13-1996 R2=C3=A2=82=AC=C2=9D and I=C3=A2=82=AC=84=A2m now back in the same spot, straight to 7000 from 5000 so not pass go and do not collect $200. Any thoughts. Rick -------- 701Driver N35 26.700, W118 16.743 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=302890#302890 ________________________________ Message 2 _____________________________________ Time: 01:18:54 AM PST US From: GRAHAM SINGLETON Subject: Re: RotaxEngines-List: Re: Tach reads perfect until 4k, then goes to 7k?? I had the same problem years ago, it happened when I reset the sensor gaps on the flywheel trigger coils to manual figures, they were very wide althou gh the engine ran fine. After readjustment the symptoms were as you all des cribe, fine up to 4K then full scale deflection. =0AGraham=0A=0A=0A=0A=0A =0A________________________________=0AFrom: Brian Davies =0ATo: rotaxengines-list@matronics.com=0ASent: Tuesday, 29 June, 20 10 9:08:09=0ASubject: RE: RotaxEngines-List: Re: Tach reads perfect until 4 k, then goes to 7k??=0A=0AHi Rick,=0A=0ASorry about the vague reply I gave. I was away from my office so could not get to the reference. I have atta ched a file from Rotax Owner Assistance Network (ROAN) which gives the guid ance. It suggests using a 200 ohm resistor across the trigger coil on the stator. I have had just as much success using a resistor across the equiva lent terminals on the back of the Tach. On the Rotax tach it goes across te rminals 2 and 3. =0A=0AI have also cured this problem by swapping over the blue and white wires in the connecting plug. In some cases the only cure w as changing the tacho.=0A=0AYou will see from all of this that there is som ething a bit marginal about the Rotax 912 tacho set up. The pick up seems to produce a relatively low voltage (3v) strangely shaped pulse when proper ly loaded but can give out as much as 100volts if not properly loaded. Tha t is why the 200 ohm resistor sometimes fixes the problem. By the way, the trigger coil produces 1 pulse per revolution. =0A=0AI have never had a pro blem with the UMA replacement for the "official" Rotax Tach.=0A=0ARegards =0A=0ABrian=0A=0A-----Original Message-----=0AFrom: owner-rotaxengines-list -server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of ricklach=0ASent: 28 June 2010 22:49=0ATo: rotaxengines-list@m atronics.com=0ASubject: RotaxEngines-List: Re: Tach reads perfect until 4k, =0A--> =0A=0ACarl and Brian,=0A=0AI=C3=A2=82=AC =84=A2ve been working with the same problem as Carl. My Rotax rev-counte r is solid until it reaches 4800-5000 then it goes to 7000, like Carl=C3=A2 =82=AC=84=A2s. I=C3=A2=82=AC=84=A2ve been searching through all the SB=C3=A2=82=AC=84=A2s, SI=C3=A2=82=AC=84=A2s, SA=C3=A2 =82=AC=84=A2s and SL=C3=A2=82=AC=84=A2s and I only found Service I nstruction =C3=A2=82=AC=C5=93SI-13-1996 R2=C3=A2=82=AC that refers to installing a tack. But I find no reference to a resister across any termin als in this document. Have I missed it or is there another document you=C3 =A2=82=AC=84=A2re referring to? Also Brian what two terminals are you putting the resister across? Service Instruction =C3=A2=82=AC=C5=93SI-1 3-1996 R2=C3=A2=82=AC has six installation configurations. I=C3=A2=82 =AC=84=A2m like most people Fig. 3 is my installation, the simple one. A ll other =C3=A2=82=AC=C5=93FIG=C3=A2=82=AC are for a Rotax Fly-Dat or a 914 with a TCU. =0A=0AAfter review all the Schematics in the 912 Install ation Manual and the Heavy Maintenance Manual all schematics showed a simpl e direct connection, without a ground, between the tack #2 =C3=A2=82=AC =C5=93-=C3=A2=82=AC=C5=93 terminal and the rev pick up. I tried that and the tack did not work at all. I then replaced the ground between the tack #2 =C3=A2=82=AC=C5=93-=C3=A2=82=AC=C5=93 terminal as shown in Fig. 3 of =C3=A2=82=AC=C5=93SI-13-1996 R2=C3=A2=82=AC and I=C3=A2=82=AC =84=A2m now back in the same spot, straight to 7000 from 5000 so not pas s go and do not collect $200.=0A=0AAny thoughts.=0A=0ARick=0A=0A--------=0A 701Driver=0AN35 26.700, W118 16.743=0A=0A=0A=0A=0ARead this topic online h ere:=0A=0Ahttp://forums.matronics.com/viewtopic.php?p=302890#302890 ________________________________ Message 3 _____________________________________ Time: 03:41:52 AM PST US Subject: RotaxEngines-List: 914 Fuel Pump From: "h&jeuropa" One of our Pierburg electric fuel pumps has failed. Has anyone found a place to purchase these in the US other than Lockwood? Jim & Heather Europa Read this topic online here: http://forums.matronics.com/viewtopic.php?p=302956#302956 ________________________________ Message 4 _____________________________________ Time: 08:34:09 AM PST US Subject: RotaxEngines-List: Re: Tach reads perfect until 4k, then goes to 7k?? From: "ricklach" Thanks Brian, I now have a list of things to try. Your time is very appreciated. Ill keep you updated as to my luck with this problem. Rick -------- 701Driver N35 26.700, W118 16.743 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=302988#302988 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rotaxengines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RotaxEngines-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/rotaxengines-list Browse Digests http://www.matronics.com/digest/rotaxengines-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.