Petter A1 starting (or not in my case)

Hi All

Sorry to post another request for help but I am trying to get my A1 to start.
The engine is now rebuilt and I have been trying over the past few days to get it to run. I have watched loads of videos and read a stack of threads with advice but no matter what I do I seem to be at the same point each time.
The situation is : Magneto (wico) set to click at TDC or a degree or two before, points set and gapped ok, plug gapped and really good spark. Could it be 360 deg out as it revolves at the same as the flywheel even though it sparks every revolution?
The carb has plenty of fuel, main jet set to 1.5 turns out, slow running jet 2.25 turns out, main butterfly just open. Governor all seems to be ok.
When I attempt to start the engine with NO choke, vapour evident in the air inlet, NO evidence of an attempt to run or fire. When I close the choke, I get extremely lively kick backs which are interesting to say the least.
Tried valve lifter to have good rotation, tried minor carb adjustments but nothing changes.
Anyone any advice?

Alan

Are you swinging it to fast? All you need do with a Petter A1 is pull it over compression slowly, you should have the impulse working as you do so, if you are swinging it like a loon and have the impulse not working then you are on a hiding to nothing.

Not going to be 360 deg out as if it was then it would be in the same place, and as it is a "wasted spark" being 180 deg shouldn't matter that much. try more turns on the mix screw, go to 2 turns from closed, is it a Solex carb?

Hi Ya

Yes it is a solex carb.
Swinging it over TDC with no choke, nothing.(but you do see petrol vapour in the inlet next to the choke butterfly) With choke on you get an exciting kick back which really is quite vicious.
I have tried minor jet adjustments and it makes no difference.
Alan

Try rubbing some pencil on the plug electrodes....

Hi Again
Tried your tip and did get one biggish back fire through the exhaust this time. Then back to the same situation.
I definitely think that either something is not assembled correctly or maybe fuel settings or the valve timing is not correct. Is there a particular setting for the main butterfly, is it too closed, I do not have much tension on the governor spring so the control arm is quite loose. Dunno
Oh well, all adds to the fun.
Alan

Right, is your valve timing right? sounds like you are getting blowback somewhere, also with the throttle butterfly this should be open when the engine is stopped so maybe you need some more tension on the spring? With my A1 I have to hold the throttle butterfly closed to start that and no choke unless it is really cold, working engine, not a show engine.

Re check the ignition timing, sounds like its firing a tad early on the induction stroke, where abouts are you?

Hi All

Thanks for the replies and advice.

Location is Bangor in N Ireland, so not just down the road for most on the forum.
I will recheck the valve timing again and basically look at everything.
I have set the timing as per everyone's instructions, ie the mag clicks at TDC.
There has to be something. How can I check that the magneto impulse is correct too.
Alan

hi there with petter a1s a big kick back is caused buy the mag being 180 degres advanced ,
just get the engine to a place were it stays put i.e bottom dead center ,unbolt your mag and rotate until the slit line up again on the coupling in the rotation direction , as i found out the hard way 2 -3 yrs back ,still have the crank scares in my leg/shin   
so its usually that simple to sort as it was with mine back then
kev

also the mag will impulse twice every 4 strokes compression and top dead exhurst
kev

It is also possible for the impulse to click perfectly at tdc but the mag timing to still be out (as was the case with my wolseley) turn the flywheel just through the click of the impulse on tdc then slowly rotate it backwards (to show the points opening without the influence of the impulse) the points should open 20 deg before tdc. My Wolseley's mag had been played with and the points were opening around 70deg before tdc, bloody thing nearly broke my wrist.

Hi All

Right. The next chapter!! Thanks to everyone for your suggestions/help
Taken on board all suggestions and rechecked the magneto. The dog that makes the magneto click looks to be in the wrong position. I ignored the impulse totally and timed the engine to 20 deg BTDC using a meter and then checked the impulse setting.
It appears to trigger mid way along the raised lobe (about 100deg past TDC) and moves the cam within the raised part only, which to me suggests it is incorrect and so has no effect to the points when moving to open around TDC. There is a second opening on the impulse system that would move the dog by about 90 deg. Could the magneto have been assembled incorrectly (I have not had it apart).
Alan

Hi Folks

SHE'S RUNNING after many years idle.

I was correct, the magneto had been assembled incorrectly. The impulse system had the dog in the wrong position.
Reassembled, check for TDC click, quick flick and off she went. Brilliant. Loads learnt for me.
Thanks for all your help and advice and my first engine is well and truly operational.
Alan      

Well done mate its like when we all start out its all trial and error and asking for loads of help still do it myself all the time though its getting easier with each new engine lol

Telemark09 wrote:Hi Folks

SHE'S RUNNING after many years idle.

I was correct, the magneto had been assembled incorrectly. The impulse system had the dog in the wrong position.
Reassembled, check for TDC click, quick flick and off she went. Brilliant. Loads learnt for me.
Thanks for all your help and advice and my first engine is well and truly operational.
Alan       

Yes it would be blooming boring if our engine's started easily every time...................or would it?    The A1 I have was put up for sale because the previous owner couldn't start it after overhauling the thing, he had the mag firing on BDC plus the throttle linkage was upside down so the butterfly was closed instead of open, I soon sorted it and it ran well.....until the coil died!  

Pete.

Good news, lovely thump to them isn't there?

[quote="blackvanman"]Good news, lovely thump to them isn't there? [/quote]

Indeed.  

Villiers wrote:

blackvanman wrote:Good news, lovely thump to them isn't there?

Indeed.  

might roll mine out for a run in celebration later , I do think they are very under rated for what they are, they are great reliable engines, it always amazes me how cheap they are to pick up for such a solid useful engine

Hi All
Just to close this thread off. Engine now running perfectly so I would just like to thank everybody for their suggestions and support over the past few days.
Alan      

Telemark09 wrote:Hi All
Just to close this thread off. Engine now running perfectly so I would just like to thank everybody for their suggestions and support over the past few days.
Alan      

That's what its all about Just gave mine half hours running, reminded me I need to do the tappets before the start of the season, or knowing me I'll get round to it at the first rally next year

[quote="blackvanman"]
might roll mine out for a run in celebration later , I do think they are very under rated for what they are, they are great reliable engines, it always amazes me how cheap they are to pick up for such a solid useful engine [/quote]

When I was looking for a saw bench to do my fire wood I kept an eye out for one with a Petter A, A1 or AV as I reckon for a work engine they are the mutts, the AV would have to of had a radiator as I didn't want all the faff with cooling tanks, and Lister just don't cut it for a "leave it outside, start it now" engine as the're just to full of fiddly little bits that can get rusted up.

Villiers wrote:

blackvanman wrote:
might roll mine out for a run in celebration later , I do think they are very under rated for what they are, they are great reliable engines, it always amazes me how cheap they are to pick up for such a solid useful engine

When I was looking for a saw bench to do my fire wood I kept an eye out for one with a Petter A, A1 or AV as I reckon for a work engine they are the mutts, the AV would have to of had a radiator as I didn't want all the faff with cooling tanks, and Lister just don't cut it for a "leave it outside, start it now" engine as the're just to full of fiddly little bits that can get rusted up.

Agreed, my A1 is the real workhorse for me at rallies, it has the honour of running an alternator which in turn powers an inverter to run the charger for my scooter. It thumps like a good'en when you put the load on but marches on with ease, I'd be stuffed without it TBH. They were originally called "The Mighty Atom" by Petter when they launched the range, anyone who owns one can see why

Got any pictures yet Telemark????

Mine...



3hp @1500rpm, has now been retired and replaced with a PAZ1 as diesel is a lot cheaper than petrol, the A1 uses a gallon a day cutting wood.....

Great job Telemark - a good thread to read and even better to see you have it running - happy days for you and as you say all part of the learning experience. you'll need a new project soon!

best

Hamish

Bargain here for someone....

http://www.ebay.co.uk/itm/161189202878?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649