Classic cars forum & vehicle restoration.

[Miken]

Its a 1927 Morris Cowley with magneto ignition, and a gravity fed fuel tank to an SU carb. Turn the fuel tap on and it should go.
This is a regularly used car last used 5 days ago.
just over a month ago I fitted a professionally reconditioned magneto and its been starting instantly on the starting button ever since.
Today i went out and its started on 2 cylinders, immediately cut to 1 cylinder then stopped.
I yanked the plugs out and they were all fouled with fuel.
I dried them off with a tissue then gave them a bit of a wire brush.
Tried again, 2 then 1 then stop.
Repeat several times. Even tried warming the plugs a bit with a propane torch (does this help?).
Laying the plugs on the cylinder head still connected to the leads produced nice big blue sparks on all 4.
Its getting late now, so Ive left it with the plugs out to let it air a bit and will try again tomorrow.
Any suggestions please?
Thanks Mike

[Kenham]

Sounds like a magneto issue, what type of magneto is it? Perhaps the internal timing of the magneto has moved , is it timed by fibre gears? Has the sprocket / gear on the taper moved?

[MVPeters]

".... I yanked the plugs out and they were all fouled with fuel. ...."

I think I'd look at the carburettor......
_________________
Mike - MVPeters at comcast.net
2002 MINI Cooper 'S'

[Miken]

Thanks for the replies,
Having wasted a load of time last evening trying to get my car to start I left it with a few stern words.
Clearly it has thought about its actions overnight because this morning I went out and checked the ignition timing which was, as far as I could see correct (within a couple of thou. see picture).
And of course, when I tried it, it promptly started straight away as if nothing had happened.
I have come up with a theory that might explain what happened.
Last time I moved the car I drove it a few meters and parked outside my house while I worked in the garage all day. Then i reversed it back in the evening.
The engine probably ran for less than a minute.
Im thinking that as I switched it off it continues to suck in fuel as it rotates to a stop, which in a hot engine would then simply evaporate out of the cylinders. At this point my engine was just a lump of cold iron. I think my engine was just full of neat condensed fuel that fouled the plugs as it sucked in more every time I tried to start it.
Its a beautiful morning here so I'm off for a drive.

[alastairq]

I'm glad the issue is sorted....

Might be worth thinking about [next time?] simply turning the engine over,with the throttle wide open?

Hopefully, this will allow lots of fresh air into the cylinders, to mix with any unburnt fuel?

[oldboy]

When I used to work on vintage boats with Magneto's we always turned off the fuel supply a few seconds before cutting the ignition.

[Miken]

[Brent29]