1845 tmd20 diesel glow plug operation

[wedge542]

how long should i hold the switch on to heatup the plugs,,,if i turn the key till the red light comes on it stays on till i let off key ot crank it,,,ive been just counting to 20 and crank but it still slow to start and when it does lots of smoke like raw fuel...

 

[Tazza]

20 seconds should be enough, the plugs could be burnt out, or the engine could just be worn, low compression making it hard to start.
Does it restart easily when warm?