F925 Yanmar diesel got noisy, ran rough, stalled, and won't run

[Creekpaddler]

After letting it sit for 10 days due to heavy rains, I fired up my F925 front-deck mower yesterday and let it warm up 2 minutes. The engine ran normally. I drove about 200 hundred feet, engaged the mower deck, and cut for 150 feet in thick, foot-high grass. Then the Yanmar 3-cylinder diesel got very noisy and ran roughly before stalling. Repeated attempts to start failed - it just stalls.

Can anyone give me some tips?

 

[Katahdin]

So...this is the used F925 with 1800hrs you just picked up a few weeks ago....?

I'd start with cleaning the entire fuel system, get the sludge/algae out of the tank, change all the fuel filters, fill with fresh fuel, and change the air filter too while you're at it.

Here's a link for troubleshooting further: Troubleshooting

 

[Creekpaddler]

Yep - that's the one. The pigeon has come home to roost.

 

[Creekpaddler]

Lesson learned: don't trust the fuel gauge. The tank was empty, but the gauge read FULL. A probe into the tank showed no fuel.

This F925 mower is supposed to be self-priming - the owner's manual states that mowers with serial numbers after 160000 self-prime. My serial number is 160381. After I filled the tank I cranked the engine. It wouldn't start - still starved for fuel. Today I'll check for current to the electric fuel pump. If it's OK, I may just bleed the fuel lines anyway. Stay tuned...

 

[Yellowfever440]

Just bleed those thing may self prime after 20 minutes of cranking. You still have to get the air out of the pump injectors and injector lines. Just loosen one or 2 injection lines until you get some bubbles then tighten and off you go.

 

[zzvyb6]

Sounds familiar to me. Even though the tank gauges both read 3/4 full (mine is a 935 with 2 tanks), the suction lines in the tanks were split at the 3/4 level line. So, it would stall out after running out of fuel. Dropped the tank and replaced the suction line. In the process of sucking all that air, the electric fuel pump failed (sounded ok, just not getting any fuel pressure). Replaced the pump with one from O'Reilly Auto parts and everything is now working fine. Meanwhile, I've learned to carry an open-end 17mm wrench in the toolbox for cracking open one or two injectors in case I run out of fuel again. Since there are two tanks and two gauges, sometimes I monitor the wrong tank and get a surprise. The suction line was not fuel line, but some kind of yellow brittle plastic that disintegrated when I pulled it out.

Not that hard to drop the tank. Pull out the sender and you will have the suction line coming with it. There was water, dirt, wax and tree leaves in my tank. Save the inlet screen and reuse it. If your suction line has broken off, fish out the screen.

 

[Creekpaddler]

Sounds familiar to me. Even though the tank gauges both read 3/4 full (mine is a 935 with 2 tanks), the suction lines in the tanks were split at the 3/4 level line. So, it would stall out after running out of fuel. Dropped the tank and replaced the suction line. In the process of sucking all that air, the electric fuel pump failed (sounded ok, just not getting any fuel pressure). Replaced the pump with one from O'Reilly Auto parts and everything is now working fine. Meanwhile, I've learned to carry an open-end 17mm wrench in the toolbox for cracking open one or two injectors in case I run out of fuel again. Since there are two tanks and two gauges, sometimes I monitor the wrong tank and get a surprise. The suction line was not fuel line, but some kind of yellow brittle plastic that disintegrated when I pulled it out.

Not that hard to drop the tank. Pull out the sender and you will have the suction line coming with it. There was water, dirt, wax and tree leaves in my tank. Save the inlet screen and reuse it. If your suction line has broken off, fish out the screen.

Thanks for the tips. My F925 has a self-priming fuel system (serial numbers 160000 and up) and there is no bleed screw on the filter housing. So I bled two of the injectors, got fuel right away, and tried starting it up. It took several attempts to keep it running. Once it was running it made a lot of noise and took several minutes before it got enough fuel to all 3 injectors. But it finally settled down to a purr and ran fine.