bought a 102 on ebay- progress or lack of it so far

[blue]

bought a 102 whcl---started it quite easily on old fuel---then put in new fuel---it ran well- --pumped water well then the magneto base locking screw came loose and it stopped---i had a lot of difficulty finding right spot to relocate the locking screw but think i have found it---tried to start but no spark---the lead between the coil and condenser was broken so took it to local auto electrician and he replaced it ---but---on turning the engine slowly by hand the points seem to stay open then briefly close then open again---i am new to this but shouldn t the points stay closed then briefly open which is the exact opposite of whats happening at the moment----advice please---regards barry

[40TPI]

No, the dwell angle on a Model 102 Villiers Mk1 magneto is approximately 39 degrees. It isn't particularly critical to within a slack handful of degrees either way.............and here's the usual picture of "one I did earlier"..........

Peter

[blue]

thanks for reply 40TPI--sorry do not understand dwell angle---looked at points again since first post---for each revolution of the flywheel they stay open then close briefly once----i thought it should be the opposite way round and that they should stay closed and open briefly once----regards barry

[Hugz]

That sounds right, they stay open while the condensor charges up and then close once per revolution which shoots off the charge to the primary coil which energises the secondary to the spark. The cam on the end of the crank has one high point which pushes the points together.

Think of the cam on the inside of a car distributor that has four/six or eight high points depending on the number of cylinders.

I think I'm about 80% correct.

[40TPI]

What you are seeing on your motor is correct. Dwell time is the time the points are closed. It is usually expressed in degrees since expressing it in seconds is meaningless unless the engine speed in
rpm is also stated at the same time.

There is one points closure per complete revolution, ie 360 degrees of the flywheel. The points are closed for about 39 of those 360 degrees. In percentage terms that is about 10.8 % of the time, the rest of the time they are open.

The scope picture shows about 1.25 revolutions. The waveform is that measured across the points with respect to chassis. The two fast negative going edges correspond to the points opening at the end of each dwell period, ie two consecutive sparks.

The operation of the cam on the points and the function of the capacitor is covered in earlier posts and else where on the www.

Peter

[John1952]

Be gentle, your turning blue a funny grey color!

[blue]

thanks everyone i now understand dwell angle and the points are opening correctly---i will go and try to find a spark----i have had my finger on the end of plug and can feel nothing----haven t quite dared to put my tongue on end of plug as recommended by another poster----regards for now blue

[blue]

i bought an engine that started and ran even on old petrol and i have been slowly destroying it ever since---searching for a spark is on back burner at the moment ----i have now started on the carb ----the throttle control was stiff so i gave the carb lashings of wd-40 and tried to replace the throttle cable which was damaged----i could not get the throttle piston out---instead i have half pulled out a sleeve which i can t see on the diagram of parts-----please see photos----http://i813.photobucket.com/albums

[woodbutchergraham]

I think the sleeve you refer to is the carb slide if its stuck ease it out by pushing through the air intake opening. But be careful not to score the inside of the carb body, there is a small bolt in the side of the carb body that the slide must line up with. Take it easy and when the slide is out check it carefully for burs or rub marks. Try the slide back in it should be a snug fit re assemble

[blue]

thanks wood butcher----i spoke to sos john and emailed photos----he calls it the air slide----i could not see it in the parts diagram---it is well stuck at the moment but now i know it is meant to come out i will give further attention-----regards blue

[blue]

hi wood butcher ---i have got it out---i need to give it a polish so it moves more freely when reinstated-----any idea of what to use----thanks blue -----ps now i have got it out and can see it---i feel rather silly---i thought it was a piston and a sleeve

[woodbutchergraham]

Take it easy at this stage use a fine wet and dry to remove any burs or hard spots. Rub a soft pencil around the inside of the carb insert the air slide if that’s what the oracle claims. Invert it (upside down) it’s easier to get it out. This should ether leave
a mark on the slide or remove the pencil from the carb body. Indicating a place to ease, with time and patience the slide should travel with ease. The question is how did this happen the only thing I can surmise that the body has been damaged on the outside causing it to distort the shape. As the bodies are only die cast threads and fittings should be treated with extreme care. Check out my holiday picks and at the end there are some pickies of a carb I repaired.

[blue]

hi woodbutcher----i thought the same thing about the distortion of carb body but not so sure now---i have to work on seagull in a shed where my boat is stored about 1/2 mile away but wife has gome visiting for weekend so engine is in bits on table at home and i am making real progress ---spent the evening moving the airslide up and down and round and round in carb body with wd40 and it now glides up and down----gapped points more accurately and now have a spark----took the tank off and tried cleaning out-- first with acetone ----got some rubbish out---then put in a dishwasher tablet and boiling water ----amazing amount of sludge came out ----repeated 3 times and then dried with wifes hair drier----putting back together today will let you know result ---regards barry

[blue]

hi --put it all back together----to paraphrase morecambe and wise i have got all the right parts but not necessarily in the right order----amal 416 carb---fuel needle valve---part 31 on the parts diagram----how does this fit in---thanks barry

[Charles uk]

There are 3 different styles of needles on the 416, post a pic & I'll try to explain.
Of the needle, float & the hole the needle fits in.