Martin wrote in
news
On Sun, 19 Aug 2012 16:25:17 GMT, Baz wrote:

"Bob Hobden" wrote in
:

"Dave Liquorice" wrote
But that sounds like fuel starvation. Is the breather hole in the tank
clear? Does it run with the cap loose? Is the fuel filter clear? Time
to dismantle inspect the tank/carb/gaskets. As it did run well before
do not be tempted to adjust any of the jets or poke anything through
orfices. Backwards washing with clean fuel or a gentle blast of
compressed air should clear any miniscule spots of gunk.

I'll second that, usually it's quite simple to cure. Either there is a
bleed tap on the bottom of the carb to let any accumulated muck out
(is that just Honda?) or you need to take the carb off the engine,
take it apart and clean it out (usually two or three screws). Old
stale petrol in the tank is probably the cause although it may be rust
from inside the tank mucking things up.
Make sure you do this in the open and away from any possible ignition
source.

Does the carb have a float?
If it does then you can often have a leak there. The float will sink and
oversaturate the petrol/air mixture.
An engine can often be started then die out after this flood of petrol.

Do we know if the plug is wet or dry after the engine stops? Is there
a spark on the plug after the engine stops?

I had a problem on an outboard like this. It was caused by the
capacitor. I also had one on a motorbike caused by a cracked sparking
plug.

Well that could be the Points. Advanced ignition timing and a weak mixture
can cause overheating. Smash the porcelain on the plug.

Baz