Jumping Starter Solenoids________A Warning

Around 1970 a friend of mine had his '49 Cadillac towed to the front of my house. He had drained the stale gasoline out (gas tanks had drain plugs back in those days) and put 5 gallons of fresh gasoline in but he couldn't get it started.

His Cadillac had a V8 engine with a 4 barrel Rochester carburetor and 4-speed Hydramatic transmission. After he cranked and cranked it with no luck I decided to do a quicky compression test on one cylinder just to see if it had stuck rings. I stuck a long screwdriver down the throat of the carburetor to hold its butterflies wide open (which wasn't necessary), screwed my compression tester into the passenger side cylinder, then jumped the solenoid.

The engine instantly fired, went to a full throttle (because of the danged screwdriver), the right rear tire started spinning while the front right tire was chattering along the side of the curb. Within about 2 seconds the front tire had jumped the curb followed by the spinning rear tire and the beast started burning its way across my neighbor's front lawn.

Running faster than Usain Bolt I caught up with the runaway Cadillac, swung its driver's side door open, jumped in, and stopped it about one foot from the corner of the next neighbor's house. Whew! After changing my soiled underwear I thought about what had just happened and why it happened.

Unknown to me my friend had left his key ON and his transmission in DRIVE. Yes, DRIVE and to this day I can't imagine WHY it was in DRIVE. It had a column shift selector so perhaps it had been in NEUTRAL and he happened to bump it into DRIVE on his way out. I'll never know.

The painful lesson learned that day: Before jumping a starter solenoid make damned sure it's in NEUTRAL or PARK and the key turned OFF unless you're intentionally trying to start it. And it's never necessary to block a carburetor open for a compression test because the cylinder will get more than enough air even with a closed throttle.