Power loss after sitting all winter

[dieselpowerfarmre@dy]

I finally pulled my Yanmar 1500 out of storage after it sitting for months, and now it's smoking and seems to be losing power. The fuel flows just fine, but I'm wondering about the return line. Could it be that sitting for so long caused a clog or maybe some air issue?

 

[avocadoman]

Yeah, after sitting for months, its possible the return line got clogged or there's air in the system. Even if fuel is flowing, a blocked return or trapped air can mess with pressure and cause smoking or power loss. It's worth checking and bleeding the system to rule that out. Glad you asked here before going straight to the dealer

 

[Astranger09]

One thing I know is that if pressure builds up in the injector lines due to a blocked return, it can mess with fuel atomization leading to smoke and power loss. Sitting that long, there's also a chance of air in the system or even algae buildup in the fuel

 

[Bidz38]

I finally pulled my Yanmar 1500 out of storage after it sitting for months, and now it's smoking and seems to be losing power. The fuel flows just fine, but I'm wondering about the return line. Could it be that sitting for so long caused a clog or maybe some air issue?

Yeah, that could happen when it's sitting for a long time and you're right to be looking beyond just the fuel flow.
First, I'd check the fuel itself since old diesel can get gunked up or have water in it from condensation.
This is the most common cause of power loss and smoking.
Try draining the tank, fill it with fresh fuel, and replace the fuel filter.
Also check the air filter if a mouse or other critter could've built a nest in the intake over the winter, which would choke the engine and cause it to smoke.
And lastly inspect your injectors if it gummed up from sitting.
If it did, a good fuel system cleaner should clear them out.