1956 Evinrude 3 HP won't stay running

I have a 1956 Evinrude 3 hp motor. It starts up very well and can run at full throttle for about a minute or two then dies. There is also other times when I can be running it at full throttle but the rpms are nowhere near where they should be and it will stay running fine. I have replaced both spark plugs and the fuel line. People have mentioned the coils may be bad, I opened up the motor and the old coils look like they have been replaced at some point and look brand new. I did not take the coils out to check the inside point but I've seen burned out coils and the outside at least looked brand new. Please let me know if you have any ideas. I've been working on this motor for a while and am willing to try anything. Thanks!


ps I have a video that I am currently uploading on youtube. When that is done uploading I will post it. Just a video of the motor showing how it runs.

Re: 1956 Evinrude 3 HP won't stay running

You have two separate problems.

#1, there is a sintered filter in the gas tank. Very likely it is clogged and not allowing fuel to flow as fast as the motor consumes it. So it runs out of fuel and dies. You are supposed to replace the filter when clogged because it is very difficult to clean. But it is $40. So, I unsolder the sintered filter and solder in a brass screen filter. EDIT: Don't ignore the simple stuff. The gas cap vent may be closed or clogged. Will it keep running if you loosen the cap??

#2. Your motor drops down to half speed because one cylinder quits firing. Cracked coils are the notorious cause, but obviously not in your case. So, check points and plugs. And wires. It is NOT the carburetor causing this. EDIT: Again, don't ignore the simple stuff. Is the spark arcing out at the plug boots?