YM2000 Blake smoke & loss of power

[Mpabe]

My YM suddenly started blowing black smoke and has lost power. When I start it, I have the throttle set wide open but when it starts the motor is usually running a low rpm. It slowly builds up to about 2000 rpm but easily bogs down under load or if in a higher gear. It just started doing this ... Can't think of anything I've changed. Any ideas?

 

[Scotty Dive]

My YM suddenly started blowing black smoke and has lost power. When I start it, I have the throttle set wide open but when it starts the motor is usually running a low rpm. It slowly builds up to about 2000 rpm but easily bogs down under load or if in a higher gear. It just started doing this ... Can't think of anything I've changed. Any ideas?

Welcome aboard


Start with the basics ....check the air filter and fuel filter and then proper bleeding procedure

 

[winston1]

Might try slowly loosening the injector fuel lines one at a time to see if one cylinder is guilty.

 

[clemsonfor]

sounds like your looseing a cylinder maybe.

 

[careyo63]

Sounds that way! But one thing does comes to mind is the Nylon Washer maybe Worn out on the Throttle linkage letting it fall. Try keeping your foot on the Throttle Pedal so you know thats not happening. My 2000's was so bad it Literally fell out and Crumbled into Pieces when I went to check it. Just bought it and was Lucky to find it. I seen my handle actually to Start falling Forward and the Rpm's would started to Drop under a Load.

 

[Mpabe]

sounds like your looseing a cylinder maybe.

What does this mean? Sounds bad.....

 

[Gary Fowler]

If you hadn't used it in a while, rats or bird may have build a nest in the intake air, pull your filter off and make sure that there is nothing obstructing the air inlet. Clean the filter while you are doing it. Black smoke usually means not enough air to burn the fuel completely.

Another thing may be the injector pump has malfunctioned and is putting too much fuel in so it is running too rich but that would usually mean higher RPM, not lower. Injectors may be bad also and not atomizing the fuel properly so it can burn.

Rat nest, injectors and fuel injection pump, check in that order, assuming that you have checked the linkage and it is opening the throttle lever on the injection pump correctly as you advance the throttle.

 

[clemsonfor]

That would mean that one cylinder is not fireing. From any number of issues. Could be lack of compression or a bad injector that is dumping too much fuel and not atomizing it proper and just driping it in...out of time somehow???

But the black smoke is either an over fuel issue or fuel that is not combusted. the black is basically incomplete combusted fuel coming out of exhaust.

My theory is your not fireing on a cylinder...thus the reason your throttle is wide open but your motor starts slow and then gains speed yet still blows the smoke. The engine can run on one cylinder...but should have a "miss" sound to it and a puff of smoke on the missing cylinder. But as the engine slowly gains momentum the RPMS would increase but so would the smoke as it sucks more fuel into that cylinder yet it still wont fire on it. But then when you try to load it up you dont have any power cause you lack the torque you need to produce it as your only fireing on one cylinder, and the load drags the engine down.

You can crack the injector lines and see if it cuts off on one cylinder and not the other.If one cylinder produces no noticeable difference when the fuel is coming out of the line when you open it thats the bad one, if one cylinder or both produce a change in engine speed you found there both fireing. If you crack one line and the engine shuts off you likely found your one cylinder that was fireing as you took its fuel supply by opeining the injector line thus taking the fuel from the one cylinder not allowing it to run.

OR you can pull of the muffler and the tiny exhaust manifold and then crank the engine and see which cylinder is puffing the smoke, which will tell you which cylinder is the problem one, but this does not mean that you dont have compression on that cylinder just gives you a place to start.

You probably cant follow my scatterbrained post...as my fingers type way slower than my mind wants it to and the thoughts come to me.

 

[Dv1988]

That would mean that one cylinder is not fireing. From any number of issues. Could be lack of compression or a bad injector that is dumping too much fuel and not atomizing it proper and just driping it in...out of time somehow???

But the black smoke is either an over fuel issue or fuel that is not combusted. the black is basically incomplete combusted fuel coming out of exhaust.

My theory is your not fireing on a cylinder...thus the reason your throttle is wide open but your motor starts slow and then gains speed yet still blows the smoke. The engine can run on one cylinder...but should have a "miss" sound to it and a puff of smoke on the missing cylinder. But as the engine slowly gains momentum the RPMS would increase but so would the smoke as it sucks more fuel into that cylinder yet it still wont fire on it. But then when you try to load it up you dont have any power cause you lack the torque you need to produce it as your only fireing on one cylinder, and the load drags the engine down.

You can crack the injector lines and see if it cuts off on one cylinder and not the other.If one cylinder produces no noticeable difference when the fuel is coming out of the line when you open it thats the bad one, if one cylinder or both produce a change in engine speed you found there both fireing. If you crack one line and the engine shuts off you likely found your one cylinder that was fireing as you took its fuel supply by opeining the injector line thus taking the fuel from the one cylinder not allowing it to run.

OR you can pull of the muffler and the tiny exhaust manifold and then crank the engine and see which cylinder is puffing the smoke, which will tell you which cylinder is the problem one, but this does not mean that you dont have compression on that cylinder just gives you a place to start.

You probably cant follow my scatterbrained post...as my fingers type way slower than my mind wants it to and the thoughts come to me.

I’m having this issue, but I replaced a fuel pump and turned to motor over with no fuel pump in, could it be out of alignment?

 

[winston1]

This thread was last addressed in 2014. However, you're not giving enough information. "If" you are hitting on one cylinder or think you are then you might try loosening the injector lines at the injectors making sure you are getting a good flow to both at that point. If so, then with engine running, slowly loosen injector line one cylinder at a time and see what happens. Be very careful as the fuel pressure will be over 2000psi.