Yanmar 2GM20Y won't run after replacing fuel lift pump.

Ralph Johnstone · May 30, 2023

Any chance you missed the fuel pump cam on the cam shaft when you re-installed the pump ? Removing and replacing the fuel lift pump is near impossible the way my engines is situated. Managed to bend the pump arm the last time I tried to re-install it after it developed a leak.

That's when I tore the ruddy thing out and installed an electric fuel pump.

kloudie1 · May 31, 2023

Did ya open the fuel tank valve after doing the work ? (assuming yes since you were able to bleed )
Just had an electric fuel pump failure on a friend's boat.. several miles offshore.. yup, we forgot to open the tank valve .. nope, it didn't run long after startup .. We figured it out quickly when we noticed the filter vacuum gauge WAY down in the red.

Sounds like lack of fuel.. air, fuel shutoff (engine kill lever) inadvertently moved while working on the pump.

Ralph Johnstone · May 31, 2023

kloudie1 said:
Just had an electric fuel pump failure on a friend's boat.. several miles offshore.. yup, we forgot to open the tank valve

Did leaving the tank valve closed damage the pump permanently ?

kloudie1 · May 31, 2023

It did not damage the pump. It is like this: Amazon.com: Facet-Purolator New Solid State Fuel Pump 12V 3-4.5Psi, 12" /30.48Cm Min Dry Lift 6558398 D72347 : Automotive
Or it can be purchased from Westerbeke (with a Westerbeke label) for about three times that price. The original was a Westerbeke and had lasted about 1500 hours.
The new pump was stopped within 10 seconds of the engine stopping .. It restarted when the key was turned back on after the tank valve was opened.

Ken13559 · Jun 4, 2023

newage1461 said:
I have an 86 Hunter with a 2GM20Y which has been running perfectly, until I discovered a slow dripping fuel lift pump. Bought new pump and installed, engine wouldn't start and run. The new pump works fine, easy to fill the small filter on the engine and bleed. When trying to start the engine it will kick and sputter, running for about 20 seconds for it's longest run. Operating the throttle lever has no effect. Bled the air out of both injector lines. But after several hours we just can't get it running ! This boat is new to me this spring, so I don't know it's history, other than the pump must have been leaking since last year as there was a strong odor of fuel in the cabin before we tried running it.
Any ideas ??

Try remove and re-fit the Fuel Pump. It's quite easy to get the lever arm misaligned from cam when fitting it. Been there done that.

MikeHoncho · Jun 7, 2023

sounds like a lot of cranking....consider leaving the inlet valve closed until it starts.

Ralph Johnstone · Jun 7, 2023

If you determine your fuel pump is working you might want to look back at hidden air in the fuel line that bleeding won't remove.

This winter I replaced all the hoses within the 2GM20F engine compartment as they were becoming a little hard after 24 years of exposure to elevated temperatures within the compartment. I ensured that every section of the new fuel lines were filled with fuel as they were assembled but one escaped me and led me on a wild goose chase.

The vertical piece leading from the secondary fuel pump going DOWN ↓↓↓ to the injector pump. Bleeding at the injectors did not show air or remove the air. I figure that the vertical tube was filled with air and that air did not move until I got into 2000 RPM while on the water. The engine certainly ran smoothly enough at low speed but started to hunt when the RPM was increased. Finally got the bright idea to disconnect the tube and see what was in there and found it to be mostly filled with air. It looked as if a small amount of fuel was able to get around the bubble if the fuel flow was small but when the flow increased, some air was pulled along with the fuel. Dribbled fuel into the vertical tube from the secondary filter and the engine ran at 3500 RPM under load without a hiccup.