Starting diesel engines for those new to them,

It used to be that in the UK for the vast majority of us, our first engine was a diesel and we soon learned the necessary procedures. Nowadays, however, many folk come to diesels after long experience with glow and/or petrol engines. For folk not used to them, hand starting diesels can seem a challenge, but provided the motor is in good condition and the fuel is fresh – i.e., hasn’t had the ether evaporate away, which can happen with poor storage, there’s nothing to it.
As Eric has already mentioned, they need a really determined flick, not a gentle prod. My preferred method is:-
1. With the motor dry, no fuel in the crankcase, cylinder or anywhere else, turn the prop over gently – not flicking at this stage – gradually increasing the compression until you feel a definite resistance – this is the piston about to shake hands with the contra piston. DON’T try to force the piston over TDC but back off on the compression. With most small to medium motors two complete turns of the compression screw is a safe starting point (once you get used to the technique, you will ‘know’ how much to back off by feel, but two turns is a good starting point ab initio).
2. Inject a prime through the exhaust port and turn the prop over gently to make sure that you haven’t put in too much and created an hydraulic lock as the piston approaches TDC.
3. Now flick –HARD. Here is where unfamiliarity with diesels leads many folk astray – they just don’t flick hard enough. The motor is unlikely to fire at this point – not enough compression. Continue flicking, gradually increasing compression as you do so until the motor fires and runs off the prime.
4. It is possible that you have backed off compression too much (much better than not backing off enough!) and that you start to feel a resistance to the flick. Simply back off compression a bit and prime again, this time a bit more generously.
5. This system is guaranteed to work provided that you flick hard enough! I used to be a resource of last resort in my various clubs over the years for folk not familiar with diesels who would come to me (BIGHEAD they call me!) saying ‘what’s wrong with this %^%*& diesel, it won’t start’. Invariably I got it going, handed it back, and told them ‘Nothing!’. Provided that the motor hadn’t been totally flooded (quite often the case) I would have been mortified if it took me more than a dozen flicks to get the motor going – usually only need about half that, and once the settings were established – sweetness and light!
Oh, one caveat – don’t use too small a prop on a new, tight motor. Back in the late 50s I witnessed (but was too smug to participate in) a bit of a pantomime at Hounslow Heath where someone was attempting to run-in a newly acquired Webra Mach-1 (a 2.5cc racing diesel, one of the best of its generation and near to the Ollie Tiger in performance). The Webra was notorious for leaving the factory with a very tight piston, so tight that it would squeak if turned over slowly as the lubricant was washed from the cylinder walls. The owner was trying to run it in on a light 6” prop, and complained bitterly that all it would do was backfire and bite. Several folk tried to tame the little beast, only to depart clutching bruised digits! For initial running of most diesels a prop a bit bigger and heavier than you expect to use in earnest makes life much easier – but DON’T let the motor labour over-compressed on such a prop or it will overheat - it will quickly let you know that it's not happy! Back off the compression until good relations are resumed!.
Hope all that helps – actually putting it into practice probably takes a quarter as long – or less – than it took me to type this!
Oh, and one last point - don't store diesel fuel long term in plastic bottles - use glass or metal. Ether can leach through some plastics and disappear into the atmosphere.
Mike