A1 running at last
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A1 running at last
Well I have been stumped and have had loads of problems trying to get her to run, seats have been cut, valves ground in, new rings and all was looking good magneto good spark, checked all timing marks, set timing as per you tube video, checked points opening at 20 degrees before TDC new gaskets, cleaned out carb again, all I was getting were spits and pops through carb and exhaust all day yesterday
( arm got very tired by now)
got a bit frustrated as checked and double checked everything, so took magneto apart and cleaned last night, put back on this morning still nothing but pops and spits, then I remember someone on here
held the throttle link in the closed position and no choke to start, thought try anything once, now to my joy 2 swings and away she went such a relief, only thing is this is the only way it starts and ticks over good but does not like having revs increased, have tried mixture setting but no joy either way, but at least it runs thats all I need at the moment, now I can get on and restore her hopefully to her formal glory.
rich07961- A credit to the forum
- Posts : 287
Join date : 2015-03-30
Age : 72
Location : Calne Wilts
Re: A1 running at last
I have one as well that was good running when I got it .but has stood in the workshop for the last 10 years must drag it out of corner and give it a swing .but I know they van play hell with your arm
All the Best with yours
All the Best with yours
tony RA- A credit to the forum
- Posts : 278
Join date : 2013-11-16
Age : 76
Location : newtown powys
Re: A1 running at last
just a word of advise. you should never run an air cooler engine without the fan cowl fitted.
Bob
Bob
Nixie- Born to be wild
- Posts : 38
Join date : 2015-04-22
Re: A1 running at last
Very short runs with no load are Ok provided you keep an eye on its temperature. When it starts to warm up shut it down.
The "only starting with a closed throttle" comment may have been mine, I've had several do that.
A likely cause is a spark plug breaking down under pressure, (or possibly shorting somewhere else in the ignition). Closing the throttle limits the quantity of air that can be drawn into the cylinder. This results in lower compression once the engine gets a little speed on. Air resistance to the spark increases quite considerably as the air pressure increases.
Consequently the voltage required to punch through the air increases proportionally. In many case this voltage becomes sufficient to jump through usually the plug insulator, resulting in no spark in the cylinder. Spark and plug looks Ok when you try it on the side of the engine because that is only at atmospheric pressure. So 1st thing is try a new plug or a known "good" plug, (I've even had new plugs breakdown under pressure, so if needed try more than one). If it still does this then you are looking for an arc gap somewhere else in the ignition secondary circuit, (ie hi tension side), that is too small. Or maybe dirt on an insulator somewhere that is allowing the spark to "track" over it. Can be a hard thing to find.
Commercial spark plug testers had a means of testing the plug under pressure. Also notice how much longer the plug insulator is outside the cylinder compared to the business end inside the cylinder, pressure is lower outside.
Cheers
Darryl
The "only starting with a closed throttle" comment may have been mine, I've had several do that.
A likely cause is a spark plug breaking down under pressure, (or possibly shorting somewhere else in the ignition). Closing the throttle limits the quantity of air that can be drawn into the cylinder. This results in lower compression once the engine gets a little speed on. Air resistance to the spark increases quite considerably as the air pressure increases.
Consequently the voltage required to punch through the air increases proportionally. In many case this voltage becomes sufficient to jump through usually the plug insulator, resulting in no spark in the cylinder. Spark and plug looks Ok when you try it on the side of the engine because that is only at atmospheric pressure. So 1st thing is try a new plug or a known "good" plug, (I've even had new plugs breakdown under pressure, so if needed try more than one). If it still does this then you are looking for an arc gap somewhere else in the ignition secondary circuit, (ie hi tension side), that is too small. Or maybe dirt on an insulator somewhere that is allowing the spark to "track" over it. Can be a hard thing to find.
Commercial spark plug testers had a means of testing the plug under pressure. Also notice how much longer the plug insulator is outside the cylinder compared to the business end inside the cylinder, pressure is lower outside.
Cheers
Darryl
Darryl Ovens- Expert
- Posts : 64
Join date : 2013-12-04
Location : New Zealand
Re: A1 running at last
Hi thanks for comments, my main objective was to get it running so I can get on with restoration, see my other post ref new project and you will probably understand why I did not want to go head first into doing paintwork and things before I knew it would run, when it finally ran I stopped and started it a few times just to see if mixture was ok and other things, not had it running since, as for spark plug I must admit I had tried a few different ones all with same result in starting, the ht lead needs changing and will get a better plug for it as recommended,also when I took manifold off and the head they were pretty black from running to rich so whether this has anything to do with starting am not sure, I am unable to remove the mixture screw seat to clean so probably that could be the problem of not being able to get mixture right. I have noticed tonight when cleaning the dynamo that the ht lead is loose on the connection to coil this I can sort when I get new lead.
_________________
Success is the ability to go from one failure to the next without any loss of enthusiasm
rich07961- A credit to the forum
- Posts : 287
Join date : 2015-03-30
Age : 72
Location : Calne Wilts
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