Polarsailor
Member
Hello there
I have a Yanmar 2GM20 that I have a fuel supply issue with. I seem to be getting air in the so I have stripped the fuel system, replaced seals, filters etc. Incorporated between the primary and secondary filters on the engine I have a diesel rated fuel priming bulb to prime the filters. I have checked the system as best as I can and can't find any leaks, however, I seem to get loads of air in the secondary filter, in fact the filter seems pretty much empty of fuel which obviously stops the engine.
I am suspecting that the issue is the lift pump. I am using the fuel bulb I have fitted to prime the filters and bleed the fuel system this seems to work well. When I run the engine it runs fine for maybe 15min then stops. If I crack the bleed nipples on the secondary filters when the engine is running I get lots of air coming out. I appear to have no air in the primary filter. When the engine stalls if I try bleeding the engine on the starter motor I can't get the secondary filter full of fuel - this suggests to me the lift pump is knackered.
What I think is happening is I successfully bleed the engine then run it, the fuel in the secondary filter gets used and draws fuel from the pipe from the primary filter. Effectively at this point the engine is gravity fed fuel due to the layout of the fuel lines so the lift pump doesn't need to do anything. After this the fuel available via gravity is used up and air is drawn into the system filling the secondary filter with air.
Does this sound a likely diagnosis? Any advice gratefully received. I have the lift pump off and am planning on getting a new one to see if this rectifies the issue.
Keiron
I have a Yanmar 2GM20 that I have a fuel supply issue with. I seem to be getting air in the so I have stripped the fuel system, replaced seals, filters etc. Incorporated between the primary and secondary filters on the engine I have a diesel rated fuel priming bulb to prime the filters. I have checked the system as best as I can and can't find any leaks, however, I seem to get loads of air in the secondary filter, in fact the filter seems pretty much empty of fuel which obviously stops the engine.
I am suspecting that the issue is the lift pump. I am using the fuel bulb I have fitted to prime the filters and bleed the fuel system this seems to work well. When I run the engine it runs fine for maybe 15min then stops. If I crack the bleed nipples on the secondary filters when the engine is running I get lots of air coming out. I appear to have no air in the primary filter. When the engine stalls if I try bleeding the engine on the starter motor I can't get the secondary filter full of fuel - this suggests to me the lift pump is knackered.
What I think is happening is I successfully bleed the engine then run it, the fuel in the secondary filter gets used and draws fuel from the pipe from the primary filter. Effectively at this point the engine is gravity fed fuel due to the layout of the fuel lines so the lift pump doesn't need to do anything. After this the fuel available via gravity is used up and air is drawn into the system filling the secondary filter with air.
Does this sound a likely diagnosis? Any advice gratefully received. I have the lift pump off and am planning on getting a new one to see if this rectifies the issue.
Keiron