For the process of elimination I keep handy a three gallon outboard motor can with 50-1 mix..I plumb the hose into the intake fitting of the fuel pump and using the primer bulb fill the system full of fuel ..prime the engine if needed..If the engine starts to die I pump the bulb to see if it will stay running...So...if it continues to stop..the problem is from the pump onwards....If it stays running the problem is between the pump and the tank..AKA..flex line pin holes..rotted out steel line..etc....I think the 50-1 mix does an engine good that has been sitting for some time...like an upper cylinder lube...I recently worked on a 1985 Chev V-8 that had a new looking fuel pump and woud only run on the primer fuel...It would not run off my boat can either....Turned out the inner rod in the cheap discount fuel pump was broken....Anyhow...I have used this idea for years especially on stern drive boat systems ..which always have fuel delivery problems...Al..
