Had a strange occurence today and wanted to ask for input.
I have a Perkins 4.108 diesel
fitted to a Velvet Drive 1:1 transmission
, installed in my Lazyjack 32 schooner. Last month I removed and replaced the water
pump and timing cover to repair an oil leak
(hole in the timing cover). Since I completed the work the engine
has been a bit hard to start with some white smoke when cranking; however the temperatures have dropped here and the engine
has no pre-heat or glow plugs so that might account for the hard starting.
Had a hard time starting the engine today in temperature around 50 degrees. Finally got it going after on/off cranking for around 45 seconds total (5 seconds cranking, 5 seconds resting, repeat).
Once started and idling, I went below to check the engine and could smell some electrical overheating
. Found smoke coming from the starter. Attempted to stop engine with manual fuel
cut-off - no effect, engine still running. Removed bell housing to air filter and stuffed with rags - no effect, engine still running. Tried fuel
cut-off again, no effect. Starter now very hot and smoking, I was afraid of fire. As last resort, to cut electrics to starter, moved battery
switch from "all" to "off", then after about 5 seconds to house bank (since I've read that running the engine with the switch in the "off" position can damage the alternator). Engine made a squealing sound for about 3 seconds, I thought it was going to seize up; then it began idling again. Tried fuel cut-off and engine stopped.
Subsequent examination of wiring
at starter shows suspected short in circuit from key to solenoid. Mechanic
friend thinks the solenoid did not disengage and that the starter was still spinning - cause of it heating
up, and also cause of engine not quitting when fuel cut off as starter continued to rotate engine.
But, here's my real question - even if this is the case, why did the engine continue to fire once I stuffed the air intake? Shouldn't this have made the engine stop firing? Even if the starter continued to engage, wouldn't I haven noticed a difference between engine idling vs. just being turned by the starter?
I can't figure out how the engine could continue to run once I stuffed the air intake with shop rags. Does this mean it's getting air from somewhere else, and if so, where?
I'm pulling the starter to have it bench checked and will be replacing damaged wiring
. But I still have the question about the air, since this would have implications in any run-on situation - I'd always planned to stuff the shop rags into the air intake if I had a run-on, but today that didn't stop the engine. BTW the engine ran at idle speed during the entire incident, did not speed up as I'd read a run-on would.
Appreciate any thoughts anyone has. Hoping there's no damage to the engine beyond the starter and the wiring.