dougknight
Well Known Member
117 hrs TT and I have developed a tachometer problem I hope someone else may have had and can help me solve.
RV-9A
O-320-D1A Lycoming (Areosport)
carburated
fixed pitch wood prop
Vans 2 1/4" tachometer gauge along with van's transducer arangement (IE VTACHGEN 2) Short one, no vacume pump extension.
Problem: Tach started showing 500-600 rpm's low on a return flight last week. After investigating and tightning the coupling arrangement that afixes the transducer to the accessory case it seemd to be ok for a short test trip around the patch. Today after start-up it seemed to be working just fine untill taxiing towards the runway it just quit and went to zero. Back to the hanger. Checked all connections at the back of the gauge and all was well. Checked all the wire connections at the IE VTACHGEN 2 pigtail, all was well. So I pulled the transducer from the engine and checked the shaft which seemed to be just fine when I notice a seal or o ring (not sure what it was) inside the coupling arrangement is damaged and in two pieces, probably from me overtightening.
I put it back together as best I could for a test run. On start up and idle it seems to be fine but once it gets to 1300 rpm it just returns to zero and will not move no matter what the engine RPM. Shut down and re-start the engine the same thing happens over and over.
Digging into the Lycoming parts book it shows a "seal, Tachometer drive, oil" part #61165 at this or similar location, but it is pretty vague.
My question is do I have a bad transducer or a bad seal of some sort. If its just a seal where can a guy get one. Was this seal or O-Ring part of the coupling arrangement that came with the transducer from vans or was it this Lycoming "seal" off the accessory case that just ended up inside the coupling arrangement after it got squished.
thanks
doug
RV-9A
O-320-D1A Lycoming (Areosport)
carburated
fixed pitch wood prop
Vans 2 1/4" tachometer gauge along with van's transducer arangement (IE VTACHGEN 2) Short one, no vacume pump extension.
Problem: Tach started showing 500-600 rpm's low on a return flight last week. After investigating and tightning the coupling arrangement that afixes the transducer to the accessory case it seemd to be ok for a short test trip around the patch. Today after start-up it seemed to be working just fine untill taxiing towards the runway it just quit and went to zero. Back to the hanger. Checked all connections at the back of the gauge and all was well. Checked all the wire connections at the IE VTACHGEN 2 pigtail, all was well. So I pulled the transducer from the engine and checked the shaft which seemed to be just fine when I notice a seal or o ring (not sure what it was) inside the coupling arrangement is damaged and in two pieces, probably from me overtightening.
I put it back together as best I could for a test run. On start up and idle it seems to be fine but once it gets to 1300 rpm it just returns to zero and will not move no matter what the engine RPM. Shut down and re-start the engine the same thing happens over and over.
Digging into the Lycoming parts book it shows a "seal, Tachometer drive, oil" part #61165 at this or similar location, but it is pretty vague.
My question is do I have a bad transducer or a bad seal of some sort. If its just a seal where can a guy get one. Was this seal or O-Ring part of the coupling arrangement that came with the transducer from vans or was it this Lycoming "seal" off the accessory case that just ended up inside the coupling arrangement after it got squished.
thanks
doug