Need guidance on getting 340 running again

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LuckyJackson

LuckyJackson

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Good Morning. W/O getting into too much personal detail, I have come into possession of a 1971 Demon that hasn't been running in 5/6 years. I was present at purchase and it ran and drove. It had some wonky wiring under the hood and I couldn't convince the new owner to purchase a new wiring harness before running it. Within a month it smoldered and melted some the wiring under the hood and in the column. He took apart the dash/column and ignition to assess the damage and that's how it remains. Under the hood is untouched from when he bought it thankfully, but there are complications when I get there. It has the red box ignition system, aftermarket Accell coil, high rise intake manifold, and a split (double) fuel line to carb (unknown make at this time), amongst other things. I need to get this car started within 2/3 months. I have a new Year One engine compartment wiring harness, but before I get to the wiring issues....The fuel has been in the tank several years and needs to go. I would think that has to be first. After I syphon what I can in the tank, I'm assuming I have to drop the tank to get the remaining fuel out. Or will it evaporate if I leave the cap off? That seems unlikely to me. What do I do about the filler stem? Is there any issues I don't foresee in taking it out? What do I do about the gas lines up to the carb? Do they need to be drained? I doubt there's anything in there after 5 years, but is there something I should do? Cleaning somehow? I guess I could just try an external gas tank to start it but it's got to be done eventually. Once dropped, is there anything I should do to the tank, or ways to determine if I should just replace it? I prefer to stay original if possible but if I can see issues, that's different. Once drained and put back in must I put fuel in immediately, or can I leave it empty/drained until I figure out the wiring?

Next would be are there any mechanical issues I should be concerned with in trying to start an engine after 4/5 years? Is there some maintenance to do? Things to check or test? Sorry I don't have any pics yet. Thanks
 
Here's what I would do. Just going off what you say since the car is not in front of me.
Drain fuel. Disconnect fuel line on both ends. Blow air through line. If clear reconnect. On engine side connect fuel filter prior to pump and one after. Refill tank. Once you've had engine running through a tank or two change filters.
Change oil and filter. Pull dist. and prelube engine. Assuming you have tool for that. If you feel ok with it can always disconnect coil wire to prelube with starter.
Pull and rebuild carb. It's probably full of that dried up fuel crap everywhere. Check all rubber fuel lines; may need to replace.
Install your new wiring harness. Personally I've never liked those MSD boxes; assume that's what you have. I just use an old chrome box with an old school Mopar elec ignition setup.
Probably alot more than this but can get you started. Check brakes and fluid is a must as well. It's been sitting. They don't like that.
 
I would start with the basics.

Pull the sparkplugs and put a little Marvel mystery oil or similar in each cylinder and let it sit overnite.

Does the engine spin over(rotate)?

If so move to spark, fuel, and fluids.

On fuel lines I remove the feed line and spray some brake cleaner in the line and use the compressed air pressure to ensure the line is clear.

A shot of brake cleaner also sprayed down the hose from the carb side. This helps the diaphragm in the pump to soften up and pump quicker.

If you have spark, pour a little fuel down the carb and see if it fires.

If so you can now fully assess the fuel lines and carb to verify they are in proper order and make any repair / replacements you feel necessary.
 
You can download a factory manual for your car, unfortunately I do not recall the link, I am sure someone will share it.
 
Wiring: I would not assume the engine harness is OK just because maybe ?? it looks that way. (Don't know what you have inspected, how closely, or if you have run continuity tests

Unfortunately, these girls are VERY VERY poorly fused. It is VERY likely with a wiring problem, that one wire got hot and melted/ welded to others in the harness. If you are going to try and repair the harness, pull it out, lay it out, unwrap parts of it at first, and inspect for heat/ melt damage.
 
Is it the original fuel tank? You can usually tell by looking at it. It's a good idea to grab a new one unless it's in good condition. Most of them need to be cleaned out. They are not too expensive to purchase. Get a factory Service Manual and explains how to remove the Tank.
 
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After siphoning out what you can get out (I recommend this Performance Tool W54154 Shaker Siphon Hose | Google) you can make up a long piece of 5/16 inch fuel hose and add a short piece of steel line to it to drain the rest of the fuel. Pinch the suction hose closed (pinch off pliers) into the fuel pump closed, disconnect it, and connect up your steel splice line to it and run your drain hose downhill to a clean five gallon bucket. Use a drain pan during the change over to catch the spillage, and you can take the discharge side loose later and catch what runs back from the line to the carburetor. You can set up a clean bucket and pour a couple of gallons through the tank to get an idea of what the fuel system is like from there. If it's the original tank and lines with the vapor recovery setup, I wouldn't be too surprised to find that the tank and fuel line both need replacement.
 
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Thanks to all for the good info. The following questions may sound dumb, so forgive me. Belvedere & Garrett....Are you saying that it's not necessary to drop the tank? Just siphon drain? That would be great if I could get away with that. Garrett, I think you're saying to use the cars fuel pump to empty the tank? I can't do that with no wiring/ignition. Or at least I don't know how. If that's not what you mean then I obviously don't understand your described procedure. What do you mean "into fuel pump closed"? Sorry. I'm not familiar with where fuel pump is yet. Aren't they attached to the tank or am I thinking of the sending unit? I'll look this week. I'm also not familiar with numerous fuel lines. Tank to carb for feed line. Are there others that should be cleaned out with air? Both hood and dash harnesses are shot. There will be many more questions about wiring when I get there. I need to solve the fuel issue and make sure motor turns. (I'm sure it will. It's been in heated garage for 5 years). That's why I'm hoping the tank and fuel lines are useable. The car hasn't seen weather. I guess I need to get under there to understand some of your suggestions. The distributer prelube, Marvel mystery oil, clear filters ideas are great. Never rebuilt a carb but I might have to try. It's taken me 2 months to get the garage in a condition to work in. Almost there. Car work starts next Monday hopefully. I'll have more dumb questions along the way. Thanks again.
 
You can siphon all the fuel you can get out, then add a gallon of fresh fuel. Then shake the car, siphon that out. Do it again. What remains should be fine when you add 10 gallons of fresh fuel.
 
Put 2-3 clear fuel filters in the line before the carburetor. As the one furthest from the carburetor fills with trash, remove it and try again until there isn't anymore trash. The downside is, there may be trash that gets dislodged as you drive it. If you still have an abundance of trash, get a new fuel tank.
 
Red Box Ignition... is it even getting any spark to the spark plugs while cranking?

Failure rates on those are high > then no start. Especially after sitting for 5 years.


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