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Ian
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 Posted: Sun Jul 06, 2008 6:16 pm Post subject: Jim's Problem Minor |
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I was giving this some thought on a long drive (Dumfries to
Wensleydale and back) and here's what I came up with ...
To run, a nice simple old engine like the Minor's needs ...
a) Compression
b) Fuel
c) A spark and
d) For all of these to happen at the same time
So the next time it plays silly buggers, I'd suggest that he ...
a) Does a compression test, in case valves or head gasket, are doing
something silly
b) Checks that the throttle is opening, the choke isn't on, the piston
is moving, the dashpot is dashing, that fuel is coming through from
the pump, that fuel isn' t dribbling out the manifold drain (the Minor
has one, from memory) and if it passes all these. tries a bit of Ready-
start (why can't we buy "Start You Bastard" here?).
c) Checks for a good fat spark at all four plugs
d) Checks the timing
(Actually I'd do the compression test last, but I'm too lazy to
reorder the above).
Ian |
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Jim Warren
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| Posted: Mon Jul 07, 2008 12:09 am Post subject: Re: Jim's Problem Minor |
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Ian wrote:
| Quote: |
I was giving this some thought on a long drive (Dumfries to
Wensleydale and back) and here's what I came up with ...
To run, a nice simple old engine like the Minor's needs ...
a) Compression
b) Fuel
and air, mixed in the right proportion
c) A spark and
d) For all of these to happen at the same time
So the next time it plays silly buggers, I'd suggest that he ...
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<snipped but kept>
It has been raining most of the weekend, so I didn't bother taking the
car for a long run, because I would have got soaked looking under the
bonnet testing things.
But I have been musing too. This was my approach:
Take the car on a good run. Instead of switching the engine off,
disconnect the fuel pump electrics and wait till the float chamber
empties and the engine stops. Switch off the ignition and reconnect the
fuel pump. Leave it 10 minutes.
Now apart from the fuel, this is exactly the scenario where it wouldn't
start. So when I turn the key, the petrol pump will refill the float
chamber while the starter motor is turning the engine. If the engine
starts, I am looking for a flooding problem caused by the spring in the
petrol pump continuing to deliver fuel while the ignition is off. If it
doesn't, I will have to think again.
But my guess is that either the needle valve isn't seating properly or
the float is set too high. Because pretty well everything else wouldn't
make so much difference whether the engine is hot or cold.
Jim |
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Dave Plowman (News)
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| Posted: Mon Jul 07, 2008 4:03 am Post subject: Re: Jim's Problem Minor |
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In article <nL8ck.21942$E41.12594@text.news.virginmedia.com>,
Jim Warren <jimwarren@OMITblueyonder.co.uk> wrote:
| Quote: |
But my guess is that either the needle valve isn't seating properly or
the float is set too high. Because pretty well everything else wouldn't
make so much difference whether the engine is hot or cold.
|
Might be worth rigging a bottle of petrol for gravity feed to prove if
it's a pump or evaporation problem.
But my bet is still ignition. Have you got a dwell meter?
--
*TEAMWORK...means never having to take all the blame yourself *
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound. |
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Jim Warren
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| Posted: Mon Jul 07, 2008 9:59 pm Post subject: Re: Jim's Problem Minor |
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Dave Plowman (News) wrote:
| Quote: |
In article <nL8ck.21942$E41.12594@text.news.virginmedia.com>,
Jim Warren <jimwarren@OMITblueyonder.co.uk> wrote:
But my guess is that either the needle valve isn't seating properly or
the float is set too high. Because pretty well everything else wouldn't
make so much difference whether the engine is hot or cold.
Might be worth rigging a bottle of petrol for gravity feed to prove if
it's a pump or evaporation problem.
But my bet is still ignition. Have you got a dwell meter?
No I haven't. Multimeter and timing strobe are all that I have for the |
electrics.
Jim |
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Rob
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| Posted: Wed Jul 09, 2008 4:58 am Post subject: Re: Jim's Problem Minor |
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Jim Warren wrote:
| Quote: |
Dave Plowman (News) wrote:
In article <nL8ck.21942$E41.12594@text.news.virginmedia.com>,
Jim Warren <jimwarren@OMITblueyonder.co.uk> wrote:
But my guess is that either the needle valve isn't seating properly
or the float is set too high. Because pretty well everything else
wouldn't make so much difference whether the engine is hot or cold.
Might be worth rigging a bottle of petrol for gravity feed to prove if
it's a pump or evaporation problem.
But my bet is still ignition. Have you got a dwell meter?
No I haven't. Multimeter and timing strobe are all that I have for the
electrics.
Jim
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Swap the strobe to number 4 and see if it hits in the same place. Same
with # 2 and 3 place a mark on the pulley and see if that hits in the
same place.
Irrespective, 90% of problems are electrical and when this has been
sorted then you go looking for other things. |
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