Maxxforce 13 losing fuel prime

There is a check ball in the primer pump assembly, and actual check valve in the Davco filter/separator if your truck has one.

 

Check the fuel line between the Davco and the hand primer. They can get loose in the fittings.

 

I just bought a prostar myself and having same issues.

 

Low pressure fuel pump could be worn out. To confirm losing prime, you would need to install a clear fuel line so you can see the line go empty where it connects to the engine. If the line goes clear after sitting for a while you still have a line problem somewhere such as at the tank or even a cracked pick up tube inside the tank. If the line stays solid with fuel but engine is still hard to start, I would say your fuel pump is worn enough it cannot draw fuel at crank.

 

Check on the bottom of your fuel tank to see if you have metal shavings. We had the same problem and our fuel pump was going out and our fuel tank had metal shavings on the bottom. We had to hand pump the primer every morning. After we replaced the fuel pump it fixed the problem. Went through 2 fuel pumps already in the last 5 years on our truck.