Light Aircraft Association

Hi all,

A quick query - for those who use the Leburg ignition system, how often have you replaced the batteries, and do you replace them on a set period?

Possibly a silly question, but is there a simple way to test the capacity of Yuasa type sealed lead acid batteries?

Michael

Good question Michael,
I have been flying my VP-1 for 10 years now using the LeBurg system.

I am on my third battery change, although having said that, I don't believe that there are any hard or fast rules regarding this. The best indicator is the volt meter. If you power it up and there is around 12+ volts showing then it's a good sign that your batteries are holding their charge.
At PtF renewal time I normally disconnect each one and do a terminal voltage check across each battery , just to make sure that they are both at 12.75 volts [ish]
You should definitely get 2 years out of them , but I tend to look at replacement at about 3 years.

Another good indicator is during start-up. If she starts OK then the batteries are probably fine. If you're having trouble with initial start up and find that slaving in another battery solves the problem then that could be a pointer.
But generally speaking, it just works so well. The consoling factor is that the chances of your main battery, stand-by battery and alternator packing up on the same flight is pretty miniscule.

Hi Chris,

Thanks for the info. The batteries on my mono were at least 5 years old, but still showed good volts before startup, and when I used a voltmeter as suggested. I've replaced them anyway as they are pretty cheap and just gives a bit more peace of mind!

I'm still having a bit of difficulty starting (always end up having to open the throttle quite a bit while swinging) but don't think it's the ignition that's the problem.

Thanks,

Michael

This has been a good reminder for me to check when we last changed our batteries!

Michael, Are you sure you're priming enough before you start? Ours normally starts very easily from cold; can be finickety when warm. But it likes a good feed before cold starts!

Hi Nick,

I normally give it 2-3 primes, and pull through 4-6 blades (throttle 1/4" open) before trying to start. If that doesn't work I clear the cylinders (8-12 blades backwards with throttle fully open), and then pull through 4 blades with throttle half open, and start with throttle open.

Is that similar to how you start?

Michael

FWIW, I prime it with 4 blades with the throttle open and then it fires, usually with the first light tug (Not "SWING") of the next blade with the throttle set for about 600 rpm idle. I don't have a primer so I drain the carb float bowl and lines before filling with new fuel and that seems to make a big difference. Pulling a sparkplug and squirting fuel into the cylinder also helps if you haven't drained it all out, ensuring at least one rich cylinder with good fuel.

I pulled a shoulder muscle with the SR4 mags, hence the fitting of the Leburg.



You've probably seen this before.
http://s82.photobucket.com/user/foggyth ... 2.mp4.html

Michael,
Hope I'm not stating the obvious here but what have you got your spark plug gaps set at ? I think that most LeBurg users opt for 0.035" - 0.040 .

Personally, I wouldn't have thought it necessary to rotate the prop in reverse D.O.R. to clear it, as my 1834cc VW likes as much juice as she can get when starting from cold.
If she has stood for some time , I have found that taking a syringe and squirting a little fuel straight into the intake of my Stromberg 150CD normally has instant results.

I give it two primes, eight blades with the throttle at idle position, then swing with throttle open slightly...might not start first go, but usually not difficult. Someone said to me that when these engines were cold, they needed to be wet (i.e. don't worry too much about flooding); and when they were warm they needed to be dry (i.e. then worry about flooding!). I have got it too wet while warm (so to speak!), and have then resorted to winding it backwards...but I don't think this should be necessary for a cold engine.

{my post crossed with Chris's!)

Hi all,

Thanks for the useful replies - I guess I was overly worried about flooding the engine. Our spark plug gaps are set to 1mm as recommended. I was flying at the weekend and certainly found the starting easier by ensuring the engine was well primed.

Michael

I think Dave Mickleburgh recommended changing them annually as they were so cheap.

If I still had G-BAPP I would probably change the system A battery one year and System B the next and alternate like that!