Problem with 1974 Johnson 2 hp

[gayle23]

I have a 1974 Johnson 2 hp which will start but only run for 4 seconds or so and then stop. I replaced the coil, points, plug, condenser, and rebuilt the carburetor. It has good spark, compression of 80 psi, and the fuel is flowing well to the carburetor. I have taken the carb apart several times but it seems to be clean as a whistle and the float and needle are operating properly. I thought the problem was perhaps defective reeds, but I have cleaned them with a very soft brush. If I hold themk up to the light I can see a VERY SMALL crack of light coming through. The lower unit is operating properly. What am I missing??? Thank you.

 

[Barramundi NQ]

Hi Gayle, there are 3 main reasons why a working engine wont start. 1 Spark. check the spark quality and gap the new plug. 2. Fuel. Is there fuel flowing thru the carb? Can you squirt a little fuel in thru the throat to test that if it kicks after you have squirted fuel, then you can trace the fuel side. 3 Air. Do you have vacuum when you pull the start rope? without air being drawn in ( low vacuum equals low compression). Of the 3 only 1,2 are the most common.
Hope this helps
Kerry

 

[Barramundi NQ]

80 psi is low for this motor??? should be over 115