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1961 Johnson 10hp

B

bresecker

New member
Recently acquired a 1961 Johnson 10hp motor. Work primer until feel pressure then try to start as per directions on motor. Will not start. Work primer until feel pressure, then continue to prime another 5-6 squeezes and motor will run for 15-20 seconds then die. Do the same process and can also run engine at higher RPM but engine will run for shorter time. Pulled fuel pump apart and no tears in diaphragm or residue from old gas or ethanol. Best next step is to re-build carb?
 
No. First step, check the compression to see if you have anything worth messing with. Second step, check to see if you have spark that will jump a 1/4" gap. Better yet, pull the flywheel to see if the coils are cracked. They always are, on a 1961 unless they have already been replaced. If they are cracked, you are wasting your time unless you replace them. Ok, NOW you are ready to address the carburetor.
 
fdrgator said:
No. First step, check the compression to see if you have anything worth messing with. Second step, check to see if you have spark that will jump a 1/4" gap. Better yet, pull the flywheel to see if the coils are cracked. They always are, on a 1961 unless they have already been replaced. If they are cracked, you are wasting your time unless you replace them. Ok, NOW you are ready to address the carburetor.
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+1

Are you SURE the fuel pump is working properly?

After the above, replace the fuel lines as well while doing the carb work.

CMOS
 
Checked compression. Book I have does not give specific psi for this engine, but says "generally" cylinders should test to 90 - 100 psi with no more than 20% differential between individual cylinders. My engine tested one cylinder at 72 psi and the other at 75 psi. Are these good numbers for this engine, or is the "generic" number given in the book what I need to see? Thanks in advance for the help.
 
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