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Thread: VW engine trouble

  1. #21

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    Sep 2014
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    It looks as though the valve adjustment has solved the problem. I had just adjusted the valves before I took it to the airport to fly it for the first time, so I guess I thought it was good to go. When I just checked the valves they were a very tight .006 so I opened them up to a loose .007 and ran it up to WOT for over two minuets and I did not loose RPMs. Now I have to wait for warmer weather to try to fly it again since my plane is an open cockpit Teenie Two. I really thank you for all your help.

  2. #22
    Dana's Avatar
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    Jul 2011
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    It doesn't seem like opening the valve lash from .006 to .007 would make any major difference. But you may have accidentally "fixed" it when you disconnected the hoses for the fuel flow test.

    I would suggest considerably more than a two minute WOT engine run before you fly it again.

  3. #23
    Aaron Novak's Avatar
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    Quote Originally Posted by Dana View Post
    It doesn't seem like opening the valve lash from .006 to .007 would make any major difference. But you may have accidentally "fixed" it when you disconnected the hoses for the fuel flow test.

    I would suggest considerably more than a two minute WOT engine run before you fly it again.

    I agree,
    There is also a temperature difference now which could be causing other fuel issues. You aren't running much head pressure on your fuel system, so it is very sensitive to vapor lock. Also your CHT was probably lower due to the colder weather, and your ignition system component temperature was probably lower. I am still thinking its thermally induced so please re-test in warm weather.

  4. #24

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    Jun 2012
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    One other item to check. I used a Great Plains gascolator. After a year, I changed the filter and replaced the gasket with the one that came with the filter. I had a similar problem and when I investigated, I found the large flat gasket that came with the filter was incorrect. It was partially blocking the output port of the gascolator and restricting fuel flow. The engine would begin to stumble after takeoff at high power. Throttling back would correct the problem. I swapped it out with an o-ring I found at a local tractor company. I haven't had a problem since.
    Best,
    Jerry Folkerts

  5. #25

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    Sep 2014
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    I do intend to run the engine at WOT before I fly again, however, the engine build instructions I got with the engine said not to run it at full power more than five minuets. It seems to me that a static run-up at full power for five minuets would be more harmful to the engine than if I were climbing out at 80 MPH for five minuets. The ram air in flight would be better for it I think.

  6. #26
    Dana's Avatar
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    Just keep an eye on the temperatures...

  7. #27
    rwanttaja's Avatar
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    Quote Originally Posted by LAWise View Post
    I do intend to run the engine at WOT before I fly again, however, the engine build instructions I got with the engine said not to run it at full power more than five minuets. It seems to me that a static run-up at full power for five minuets would be more harmful to the engine than if I were climbing out at 80 MPH for five minuets. The ram air in flight would be better for it I think.
    Perfectly true, but it's better for the engine, not the aircraft. An unexpected loss of power on the ground results in a furrowed brow, an unexpected loss of power in flight results in furrowed ground.

    The engine build instructions allows a five-minute WOT static run, so I'd do that. I've read too many accident reports where the pilot thought that an engine problem could best be checked in-flight.....

    Ron Wanttaja

  8. #28

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    Oct 2014
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    I had loss of power on two occasions. The first time the engine just slow down. The second time the engine stopped and I made an off-site landing. In both cases the weather was very hot and I discovered that my fuel line was very close to my exhaust pipe. I assumed I had a vapor lock and installed a fuel pump. Have not flown it sense but I hope it will work

  9. #29

    Join Date
    Nov 2012
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    1,609
    After a good warm up my VW started to run rough. Lower the throttle and it would clear up, then throttle back into her and she again would start running rough. This was after I had the engine bored and stroked. Bigger jugs, crank, rods and pistons. I found the oil level was a little to high. When it warmed up it started to foam. Lowering the oil level a little helped in my case. This could be your issue to. You may be using a little to much oil.

    Just a thought.

    Tony

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