How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Tan Your Own Question
Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10621
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
25721800
Type Your Boat Question Here...
Tan is online now
A new question is answered every 9 seconds

I have a Perkins 4-108 and I keep getting air in the fuel lines

Customer Question

I have a Perkins 4-108 and I keep getting air in the fuel lines after engine shuts down and sits over night. I bleed the system then it will start up again and run like a top. I have checked all connections but wonder if it is a problem with the return fuel line somehow. Fuel tank is below engine. I have heard that Bermuda 40s used to have this problem chronically with Perkins but can't understand why. Thanks. Peter from Marblehead
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.
Hello Peter. My name is***** is due to the check valves in the lift pump they are not seating completely and the fuel is siphoning back into the fuel tank. You can install a anti siphon valve in the fuel line where it connects the the fuel tank or install a shut off valve at the same location. Turn the fuel off when you aren't using the engine. The anti siphon valve has a check ball that closes when the engine isn't running keeping the fuel from siphoning back into the fuel tank. click here Does this make sense?

Related Boat Questions