How do you start an engine that has been sitting for a long time?

Answer

I am going to assume the engine was in a car. I'd be surprised if the battery is any good at all, sitting this long, it's plates have probably sulfated so badly it isn't likely to take and hold a charge.

If you do try to recharge it, make sure the cells are covered with DISTILLED WATER & try recharging at a very low rate, say from 2.5 to 6 amps. It may take 4-5 days to brake down the sulfates & recharge at this rate, but I doubt the battery will be any good, having set unattended this long, so I'd plan on a new one.

You'll likely need new coolant & heater hoses too, maybe a new belt/s.

If this puppy was rode hard, put up wet & none of the fluids were changed before storage, I'd begin with ALL new fluids. Brake fluid, Coolant, Engine oil, Re-lube the wheel bearings, Tyranny lube, Drain the gas tank & the fuel lines, if the old gas is still in there, ya gotta get rid of it.

Refill the tank with fresh gas, with 0.4 oz per gallon of Marvel oil mixed in with the new petrol. After you run a tank or two through it, I'd change the fuel filter too.

I'd remove the spark plugs & squirt about 4 tablespoons of Marvel Oil in each cylinder & let it sit over night.

Then remove the plugs & disable the spark.

Then crank the engine for maybe two 15 second periods, (so as not to overheat the starter) to distribute the Marvel oil in the cylinders, build oil pressure & prime the fuel system.

Then replace the plugs & enable the spark & start her up.

Don't try to roll the car, as the wheel bearings may be welded from all the vehicles weight being on them this long, clean & re lube them first.

I don't know what to tell you about the tires, as we don't know under what conditions it's been stored.

First answer by Clay. Last edit by Clay. Contributor trust: 3453 [recommend contributor]. Question popularity: 75 [recommend question]