I have bought a car off a friend and i've seen the engine running a while ago, since then the carb became loose. When i got the engine i fixed the carb and check for any air leaks - none fuel was pulled throuh when turning it over fuel mixture was correct. I have built my own glow driver which puts out about 1.5V the glow plug glows brightist red with that - but the engine would not start, not even a hint or any ignition - i upped the voltage to 2V - glow plug now glowing white - engine started but after it had turned over about 2 turns it stopped - check the glow plug and it had burnt out - i had checked the glow plug on the bench for about 30secs to make sure voltage wasnt to high - is it my glow driver at fault here ? ( i have another engine showing similar symptons allthough i managed to start it on 1.5v after about 2 hours and a hair dryer !!! but havent managed it again ) what am I doing wrong?!?!?

Thanks
James Warner

Glow plugs are made to be ran on 1.2 volts. 1.5 volts would be the VERY maximum. Voltage isn't exactly what you are after though, it is current. Currrent is what makes the element glow. What you need is a glow driver that supplies 1.2 volts with an adjustable current. I would say that MOST plugs will go bad on 2 volts.

Without getting into great detail, OHM's law explains this.

Have you tried a drop or 2 of fuel down the carb to prime? 1.5E should be pleanty if there is compression and fuel. It should pop a few times. If it does and that is all you can get to happen, you may have some kind of blockage or air leak in the fuel line.
Try priming and see what happens.

Good luck

Jimmy

Hi!
The glowplug should glow orange -yellow and most glowplugs made work at 1,5V some at 2v (ie.Taylor) non at 1,2v.
Always use a 12V ,7-12A motorcycle batteri...those small 1,2v ni-cad batteries could of course be used but most people rely on a beefier battery in their flight boxes to power their fuelpump and electric strater, the 1,2v ni-cad could be used as a back-up though.
First ...hold a finger (thumb) in front of the carb intake and see if the engine can draw fuel when you turn it over......if it can
then try to start it again and do this at idle (that is with the carb open 1,5-2mm). When the engine starts.....
give full throttle and adjust for nearly max rpm, slightly rich and take away the glo-clip.



Good luck!
JK
Sweden

My glow plug was rated 1.2 - 2 V

and yes my pack can deliver enough current - it's built with 3 parrellel ni cd cells...
yes it would pop occasionally, but would started straight away on 2 plugs @ 2V ( supposedly within their maximum ) im thinking its the voltage thats killing them but why won't they start on lower? what colour should the plug glow?
James

reading your post jaka - i was posting when you posted yours...

im trying to start on full throttle - is that a bad plan?
James

Mine looks like this with 1 fully charged 1500ma Sanyo cell.

This is a Fox gold plug.

Jimmy

thats far brighter than mine ever was - maybe i'll buy a new plug and borrow a consumer glow driver from a friend - and c if that helps...
James