Starting Up a Sitting Engine


You see a Jeep sitting by the roadside, or in a barn, or in a junkyard. You find out it's for sale for such a great price that you buy it on the spot. Or you're a bit more cautious, and you want to see how it runs, or if it runs. Either way, what should you look for when you're ready to start it for the first time? This page has some advice.

Find it

Begin With the Gas Tank

In response to a question posted on the CJ-3B Bulletin Board, regarding a Jeep that had been sitting for three years, Jim Sammons suggested first ensuring that the engine could get a supply of clean fuel: "There should be a drain plug on the bottom of the gas tank located next to the fuel outlet line. Unscrew it and drain the old fuel. You might want to disconnect the fuel line from the tank to pump and either flush it out with new gas or blow out the old gas with compressed air. Disconnect the fuel line from pump to carburator and do the same. Depending on what type of carb you have on the engine you may need to remove the carb to drain the float bowl. Since it has sat for three years it might be a good idea to pull the top and look in the float bowl to see just how much sediment and corrosion is in there.

"If you don't know anything about the engine, I would try to start it before doing too much to the carb. Make sure there is oil in the engine, but don't change it yet unless there is water present. The reason for all this is, you don't know what the lower end or valve train is like. You need to hear it run before you put any money in it, just in case it has spun bearings or burnt valves.

"Valves may be stuck from sitting. You can free these up sometimes by slowly pouring automatic transmission fluid into the throat of the carb while it is running. It will smoke like hell but may or may not un-stick the valves. If it has sat with the coolant drained, the seals in the water pump may have dried and cracked, so you may have to replace it. If the engine still has points in the distributor, you may have to use a small file to dress up the contacts to get fire to the plugs. The main thing is try to get it running without spending any money till you know what you have."

Early timing marksIan Fraser: "Timing is everything! While trying to awaken the Hurricane after new plugs, wires, oil and fresh gas, I experienced what mis-timing can do to one brand new muffler and one's hearing. After several cycles of attempting to start, and minutes passing in between each cycle while making adjustments, I tapped the start button on my temporary panel and heard the loudest KERBANG ever! I lost hearing in both ears (they are still ringing lightly after 24 hours), felt a flash of compression against my left lower leg, and destroyed a brand new Walker muffler.

"My friend standing next to me and making the timing adjustments claimed I darn near jumped over top of him and he's 6'3". I know I lost consciousness for a split second and total hearing loss for probably 10 seconds. Split the muffler open along the seam worse than any popcorn kernel could ever dream of popping like. Happened to see the same results couple years back in another 3B owner's garage in Ontario. I now have an identical muffler and story. Big item is danger of losing hearing, so if you're attempting to awaken an engine I highly suggest removing muffler, triple checking plug wires, setting timing and replacing rotor cap and button. Caution!"

(See also Air-fuel ratio on Wikipedia.)

What if the Engine Won't Turn?

Lane Van de Steeg: "The '58 I bought has a seized engine. Everything I've read says to try to get it running before stripping it for restoration. This may help identify parts or assemblies that need particular attention. My question is what kind of penetrating oil or other fluid should I put in the spark plug holes, carb, oil fill, etc. to help free it up? I do not know why it seized. It was that way when the previous owner bought it three years ago. Also, since it hasn't moved on its own for at least three years is there anything else I should do or be wary of?"

MarvelMahlon Gridley: "Many people say to use Marvel Mystery Oil. I would think any brand of penetrant oil would do the trick. This would go in the spark plug holes. Put some in each hole and let it sit. I have heard of this taking several weeks to work with daily checks on its progress, adding more penetrant as needed and trying to turn the motor over with a socket and breaker bar on the crank nut. Be carefull not to put to much pressure on the nut as you could break internal pieces such as a rod or the crank. The only other thing I would suggest being aware of is possibly the clutch plate being stuck on the face of the flywheel. I would suggest a thorough inspection of transmision and tranfer case oil levels also as they will sometimes have moisture in them from sitting."

Scott Blystone: "Remove the starter before trying to turn the engine from the front nut (1 3/8 " socket on 3/4" breaker bar). A jammed starter will prevent engine from turning.

"I think you should remove the rocker arm cover, the rocker arm assembly, the carb, the thermostat housing, the oil filter and the head. Then you can see what it going on. Put about 1/4-cup Marvel Mystery Oil on top of each cylinder and go to bed. In the A.M., see which cylinders have not leaked oil past them -- these are the seized ones. If none are seized you may have a bent rod, bent valve, warped crank or cam.

"For seized cylinders: drop oil pan and unbolt piston rods at crank. Place a round piece of wood the diameter of the cylinder on top of the cylinder. Then use a one foot section of broomstick or the like on top of that and start pounding on the cylinders with a 5 lb sledge. Do a few whacks on each cylinder and then move to the next one. Keep going in order until she comes free. Its always possible that you will chip a cylinder this way but they are $19 at NAPA. Once you have the cylinders moving, you need to keep cranking, keep washing the walls with oil and wiping out the gunk. You can also polish the insides of the cylinder by wet sanding with 600 grit or finer sandpaper and Mystery Oil."

Jon Paulsen suggested: "WD40 or very light oil to start with, or even kerosene or kero/oil mix. If it won't go, try automatic transmission fluid (its high detergent helps), maybe mix it w/ kero. Kroil would be great if you have it. You'll have a heck of a time getting it to start with oil or ATF in the cylinders. After you get it to turn over, use a lot of WD40 to dilute the oil, and WD40 is great for starting 'em up as it's flammable and it helps get some compression on the unseated rings. Old junk yard dog told me the WD40 trick."

Curt mentioned another product: "Many of the antique tractor crowd have been cheering about a product called Blaster PB. It comes in a spray can at the hardware store. It claims to eat rust like crazy. I've tried it on a couple little things but nothing too exciting yet."

Clarence Blalock: I just wanted to pass on a miraculous product I found while trying to start a seized boat motor. It is a mega-penetrant called Gibbs and it is amazing. It worked on the boat motor and on an old rifle that hadn't been touched in 8 years. I just acquired a 1979 Cherokee Chief project and I'm sure I'll be using Gibbs on it. I haven't found it in the stores but it is available on their website. I hope this may help someone out down the road."

The pictures at the top of the page show Stephen Gallagher's 1955 CJ-3B as he found it in a junkyard in New Hampshire, and had it loaded onto his trailer for the trip home. (See more photos of Stephen's Jeep on the 1955-56 Owners & Photos page.)

Thanks to Stephen for the photos, and all the contributors. More comments welcome on the CJ-3B Bulletin Board. -- Derek Redmond

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Last updated 19 July 2013 by Derek Redmond redmond@cj3b.info
All content not credited and previously copyright, is copyright Derek Redmond