Aeronca-E113 Problem.

[LANTAIN1982]

Some time ago I built the Aeronca from the design of Les Chenery. Deviations I made were, it was made from solid and I introduced a Hall ignition system rather than the points specified.   Apart from a vicious backfire which spun the prop off I have had no success in getting it running.
I feel the supply of fuel to the firig point is the problem due to the manner of the rather complex intake system. see photos.

My qestion is has anybody made this engine and had success in running this design?   Current thinking is to remake the intake system to a top mount intake with a Howell type  carby.     Any advice or experience would be appreciated. Thank you.

[michaelr]

That backfire may be your ignition timing is way too far advanced, I think with a Hall sensor the spark occurs after the magnet passes the sensor it may be worth checking the timing.

Michaelr

[Roger B]

Have you made the basic sequence test? Remove the rocker covers, unscrew the spark plugs and let them rest on the cylinders so you can see the sparks, then bring the first piston to TDC where the exhaust valve is closing and the inlet valve is opening. Slowly turn the engine by hand and watch the sequence:

The exhaust valve should close and the inlet valve should open and remain open until after BDC.

Check that the spark plug sparks shortly before the piston reaches TDC.

The exhaust valve should start to open before BDC and close shortly after TDC.

Repeat for the other cylinder.

If you have good 'bouncy' compression and the sequence is correct you should get some results. The somewhat tortuous intake system may well restrict the performance but you should get at least some pops.

Have you sprayed fuel directly into the intake?

[cwelkie]

I have built this model from some of the original castings.  It too was built with a Hall Effect sensor; in the distributor.

The engine ran well.  I think blaming the intake system may be chasing at ghosts.  Especially given the evidence of a large enough backfire to throw a prop.  I believe my engine suffers from low compression due to leaky valve seals.  This may be in due to, in part, the separate seats and my lack of experience when building it.  (This was my first 4 stroke cycle model engine ... go figure.). Never did around to tearing hit down to resolve the compression - other projects beckoned.

Your Aeronca will run once you work through the possible causes.  It's not a powerhouse but it will run just fine.

[petertha]

I will mention this gadget which detects hall sensor on/off independant of the ignition module so you can focus on firing signal as a function of TDC. Yes, magnet enter/exit/center can vary signal trigger as a function of rotation angle, thus timing. The gadget saves you removing plugs to watch a spark & (from what I have read) some risks to certain ignition modules that dont respond well to certain setup movements - slow prop turning, backing up or inadvertantly parking at/near the spark signal. This aspect I am sketchy on so dont hold me to it. For electronics inclined there is probably a more bulletproof instrument but the gadget is plug & play. The LED lights up & & buzzer comes on, pretty simple. I also found its a weak proxy for magnet strength. A strong signal makes a clear indication. But if magnets are spaced further away, or other interference issues, the LED/buzzer becomes weaker. Its just qualitive but it is a something. Good luck, nice engine.

[Jo]

I have seen a few Aeroncas run, they are nice runners.

What is you earth connection resistance from the ignition unit to the spark plug like?

Jo