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1956 Evinrude 10 hp Will not stay running HELP!!

JMan30

New member
I have a 1956 evinrude 10 hp that sat for 5+ years in the woods. I completely rebuilt the carb. put new points and condensers, plug wires, Champion J6C equivelent autolite 303 spark plugs new fuel lines, cleaned filter in carb. The gas tank pressurizes fine (just noticed a small leak today). Starts right up runs for 10-30 seconds rev's up and dies. I cant for the life of me figure out what the issue is. ANy and all help is appreciated.
 
You have to make sure the tank is pressurizing. The air line coming from the crankcase must not have any leaks, also the tank must not have any leaks, in this case air. They commonly leak at the gasket or cap. The priming pump uses the same fuel pickup tube and screen so if it primes up and runs okay for 30 seconds, then it is likely a tank pressurizing issue. You can check for air leaks at the tank gasket with dish soap mixed with water. Test while the motor is running. I suggest 1 part dish soap to 5 parts water. After the motor has run and you shut it down, the tank should hold pressure almost indefinitely. Just open the cap and notice the pressure escaping.
 
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Do the single fuel line conversion. There are several videos on how to adapt the intake manifold into a pulse port for a standard pulse pump. Then you swap out the fuel connector fo a standard primer bulb fuel line.
 
Yes that is a good option, but it all depends on the condition of the original fuel tank and pump. The Siamese hose is still available as well as replacement O rings for the connector. The closed fuel system without fuel pumps to fail is pretty ingenious. I have at least 30 of these still running great.
 
The sintered metallic filter inside the fuel bowl can be difficult to clean thoroughly. What did you use to clean it? Will it run properly with the filter temporarily removed???
 
Cider vinegar overnight or if bad, soak in muriatic acid for an hour or so. Then flush with baking soda and water. I prefer the showerhead shaped screen versions.
 
Carb cleaner will work okay in some cases. If the material inside the filter is old fuel/oil residue, shellac, for instance.......carb cleaner is not very effective. Acid will break down the substance that is bonded in the tiny chambers within the composite filter much more effectively. If you have a rusty tank from old fuel remnants, acid will make it like new again. Problem is that the acid will remove most, if not all of the zinc as well and after that, the tank can get rusty easier. Old aluminum tanks will become like new again with no problems. You can put in some small crushed rock, or even 1/4 inch nuts, to shake around too. Muriatic acid will remove the rust and deposits, in most cases overnight. Final clean with hot water and baking soda, then clear hot water. Blow with air and/or vacuum then hair dryer. Carb cleaner or lacquer thinner or gasoline other small parts and your good.
 
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I u se the same method,muriatic acid on the briggs and Stratton lawnmower metal fuel tanks to remove rust, If you leave it in there too long you will not have much metal left
 
I get the 31 percent solution, you get to know the soak times based on experience. Some tanks I finalize with Kremcoat. They make an alcohol resistant that is darn good. Did a fuel tank on a 1000 Honda Goldwing in 1996, its probably still running. On these bikes, they set a fuel tank on a table, then build a motorcycle around it.
 
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