Posted by David Sherman on Tuesday, October 16, 2007 at 13:15:26 :
In Reply to: starting a motor thats been sitting...... posted by John on Tuesday, October 16, 2007 at 10:36:11 :
I once bought a 1958 5 kW military genset with a cute little Hercules 4-cylinder flathead motor. There was only 60 hours showing on the hour meter. I was eager to get it going so I filled up the radiator (!) with water, filled the crankcase with oil, hooked a jerry can to the carburetor and fired her up. She started up and ran like a champ, within a minute or so, she started making noise, and within a few minutes there was a banging from the front end like somebody was inside whacking on it with a sledge hammer. I reluctantly took the whole engine apart and found pistons and cylinders with absolutely no signs of wear (the 60 hours was probably correct), but a handful of shavings in the bottom of the oil pan that looked like they'd come off a lathe. The #1 connecting rod had chewed right through the crankshaft bearing and well into the crankshaft. Either the oil passage in the crank was clogged or some large piece of dirt or rust had gotten in there. I was lucky to find an NOS crankshaft for it, along with NOS rod bearings, and eventually got it running well. It sucks a lot of gas, for the power output, so I don't use it, but it's kind of a historical curiosity.
The lesson is, when you start up an engine that's sat for a while, let it idle and listen carefully. Shut it down if anything starts to sound bad. Then rev it up, and again listen for a while. If I had shut the generator down as soon as I heard noise, instead of stupidly hoping that my ears were wrong or it would "work itself out", I could have gotten away with just cleaning out the oil passages in the crank and putting in new rod bearings, rather than having to replace the crank, which I was lucky to find on something that old and odd.