RICK ANSWERS YOUR QUERIES
OIL BE BLOWED…
Kavan Crews’ 1955 Francis-barnett starts readily, but will only run for a few seconds before cutting out.
Failed crank seals in the 225cc Villiers 1H engine seemed a likely suspect, but the engine has been rebuilt by Villiers Services, who also overhauled the original Villiers carburettor. An electronic ignition conversion suggests the sparks are OK, so Kav’s running out of ideas.
In cases like this where the fuelling, engine health and ignition have all been sorted but it still doesn’t work, there are just two possibilities: either one of them isn’t sorted after all or it’s something else altogether. Stale petrol causes problems, but the fuel was fresh. It’s worth bearing in mind even new plugs can be faulty, too. And what about fuel mix? Originally Villiers specified 20:1; updating to a ratio for modern oils, say 30:1, will richen the mixture (less oil = more petrol : 1) so the carb may need adjustment. It’s also worth draining the crankcase as petrol can evaporate leaving a build-up of neat oil.
Returning to ignition, it occurred to me that these motors had antivibration rubber bushes built into the engine mountings. Given that the ignition coil is mounted remotely from the engine, an earth connection is needed and this is included, alongside the low-tension and lighting wires, in a block connector on the crankcase. Electronic ignition usually needs a good earth, so if the system has a black box with an earth lead, this will probably need to go the crankcase not the frame.
Thinking I’d got the answer, I got back to Kav – but he said he’d reduced the oil to petrol ratio and it was now running better. Me and my big ideas... but well done for sorting it!
‘FAILED CRANK SEALS IN THE ENGINE SEEMED LIKELY, BUT IT’S BEEN REBUILT’