Petter M Running problems

Hi
I have owned a restored Petter M type for the last year. At the first
rally of the season it ran fine all day, but since then it will only
run for around an hour, after which the plug it too sooted up for a
spark to jump the gap, therefore the engine stops. Replacing the plug
means the engine will start straightaway. The obvious problem would
then seem to be that I am running the engine too rich, but if I cut the
fuel back any further it spits and coughs and misses and so on. I used
to be able to cut the fuel back quite a lot more without this
happening, but now I can't.
I have tried various spark plugs including Champions and old
lodges (which have been most successful but still not going much over
an hour).
A while ago I removed the adjuster needle form the fuel chamber
and found the taper on the end to be quite burred - is this the
likely cause of my problem??
I have tried various loads to run the engine under but this
doesn't make much difference in the long run.
Any suggestions would be greatly appreciated as I am only 15, and
not yet very experienced.
Thankyou.
Reply to
Petaman
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A bent or burred needle will certainly give rise to the symptoms you describe. A lathe is best but very careful use of a fine file and emery should do the job. If sorting that doesn't cure it do come back as there are plenty of other more obscure possibilities. Is the spark good?? hth
Reply to
Roland Craven
Huge spark - just had the mag rewound
Reply to
Petaman
Interesting. In my and others experience a 5hp in good nick simply will not run well without a decent load. Its quite possible that a weak spark enabled it to appear to run OK before. The needle still needs sorting though. ttfn Roland
Reply to
Roland Craven
Interesting. In my and others experience a 5hp in good nick simply will not run well without a decent load. Its quite possible that a weak spark enabled it to appear to run OK before. The needle still needs sorting though. ttfn Roland
Reply to
Roland Craven
Thankyou for your assistance - I will have a look at the needle this weekend.
Reply to
Petaman

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