160 fx problem
10-03-2006 | 07:55 PM
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From: Rio Rancho NM MI
160 fx problem
Bax I copied this from the question forum this is a head scratcher and keeping me up nights
Don
Bens 160 fx is in a Giant Ucan do -side mounted with a Bisson pitts muffler and 1 exhaust plugged off
we reproduced the problem in my shop -simply by running it after we had pulled all the lines -cleaning the remote needle- checking for holes -airleaks , pulled the tank apart, etc . we started the motor held the fuse then started to slowly tip it slightly up, all was good till about 45 degrees and it suddenly stopped just like inflight conditions. This motor runs excellent on the ground and in level flight. good transition, nice power at top end, reliable idle, 18/6 zinger, he is running 15% fuel 18% oil, Byron I believe, A warm Glo plug
Ben experiances this problem on split S entry or attempting stall turns with a dead motor each time.
the tank location is in the stock location We find no foaming or air bubbles
It is a head scratcher for sure. Seems like everybody who uses a pump just takes them off later so that really isnt a cure. There are literaly hundreds of these out there with the same setup, and i have not heard of a problem like this, We are at about 1000 ft altitude at our field
The carb does not seem to be loose in the barrel but there seems to be weak fuel draw on the upline I have wrinkled my thinking cap on this one. anybody else got any input as to cause ?
Don Olsen
Evening Air Hobbies
Don
Bens 160 fx is in a Giant Ucan do -side mounted with a Bisson pitts muffler and 1 exhaust plugged off
we reproduced the problem in my shop -simply by running it after we had pulled all the lines -cleaning the remote needle- checking for holes -airleaks , pulled the tank apart, etc . we started the motor held the fuse then started to slowly tip it slightly up, all was good till about 45 degrees and it suddenly stopped just like inflight conditions. This motor runs excellent on the ground and in level flight. good transition, nice power at top end, reliable idle, 18/6 zinger, he is running 15% fuel 18% oil, Byron I believe, A warm Glo plug
Ben experiances this problem on split S entry or attempting stall turns with a dead motor each time.
the tank location is in the stock location We find no foaming or air bubbles
It is a head scratcher for sure. Seems like everybody who uses a pump just takes them off later so that really isnt a cure. There are literaly hundreds of these out there with the same setup, and i have not heard of a problem like this, We are at about 1000 ft altitude at our field
The carb does not seem to be loose in the barrel but there seems to be weak fuel draw on the upline I have wrinkled my thinking cap on this one. anybody else got any input as to cause ?
Don Olsen
Evening Air Hobbies
10-04-2006 | 10:16 AM
#2
My Feedback: (11)
RE: 160 fx problem
If the engine leans out when the nose is raised, then the difficulty is simply a lack of fuel pressure to the carb. Either the muffler's not delivering enough pressure, the fuel tank's too far from the engine, the fuel line's too small, there are leaks/kinks in the fuel line, or a fuel filler valve is leaking air.
One solution for larger engines is to re-plumb the fuel system with larger tubing. You'll have to wire-tie everything in place because the larger tubing doesn't grip the metal nipples as well as the smaller tubing. We also re-plumb the tank with larger tubing. Many tanks won't allow you to do this. Make sure you have one that does.
If the engine will run "all day" on a test stand with a good fuel system setup, then there's nothing wrong with the engine, and you have to start checking out the engine/airframe/fuel system combination.
[edit for typos]
One solution for larger engines is to re-plumb the fuel system with larger tubing. You'll have to wire-tie everything in place because the larger tubing doesn't grip the metal nipples as well as the smaller tubing. We also re-plumb the tank with larger tubing. Many tanks won't allow you to do this. Make sure you have one that does.
If the engine will run "all day" on a test stand with a good fuel system setup, then there's nothing wrong with the engine, and you have to start checking out the engine/airframe/fuel system combination.
[edit for typos]
