The grinding of, usually, maize (corn) to provide flour for the main meal (bugali – stiff corn-meal mush eaten by hand) of the African folks had been done for years by hand with a small rock on a larger rock. There were special rocks, shaped by years of use, that were passed down through families for ages. In fact, it wasn’t unusual for a new bride to bring a grinding stone to her new home or village.
Passing of time brought mechanical grinders – a mill run by a Petter or Lister deisel (it could be petrol -gasoline-, but these 2 engines were deisel) engine. The grinding was done much faster and with less physical energy needed – though the owner of the mill charged for his services! Folks flocked to these mills to get the job done. Instead of spending time hand-grinding for the next meal, now they could get milling done once that would last for a week or so, though they had to make sure not to do too much because if not used within a reasonable time the flour could sour or get weevils in it!
A church elder on the station where we lived, who was also the head attendant in the local dispensary, had saved up funds for the purchase of a mill. He purchased a grinding mill, with a Petter engine to run it. I helped him install it in a house he had built – constructed a concrete base with bolts embedded to secure the whole apparatus.
The dealer from whom he purchased the engine told him to change the oil and filter after about the first 100 hours of operation – the “run-in” period. He should make sure the oil was clean and never to re-use oil that had been taken out during a change.
After he performed that first maintenance, he ran it for a fairly long time grinding people’s corn. He checked the oil level periodically to make sure the level was where it should be. However, he noticed the oil getting very dark – which is to be expected in diesel engines using Rotella oil. He thought it was time to “clean” the engine internally.
So, what did he do? He emptied out the oil, installed a new filter – and put in kerosene instead of oil! His object was to just turn the engine over a bit by hand to circulate the kerosene which he expected to clean things up inside.
But, just cranking was tiring. He decided to try and run the engine a bit. And it started! I guess there was still residual deisel fuel in the pipes leading to the injectors. Anyway, it ran enough to seize up. With a clank, it stopped. He couldn’t even turn the engine using the crank handle. Up he came to me to seek assistance. I went down with him to his mill, found out what he had done and gave him the bad news.
The engine needed complete overhaul – bearings, rings and possibly the fuel pump and injectors. My job – to take it off the concrete base, put it in my Land Rover, take it to the dealer for repair, bring it back several weeks later and remount it and get it running for him again. In the mean time, people who had counted on an “ishelo” (grinding mill) had to go back to grinding on those age-old rocks. They sure were glad when things were working again!