I am working Bobcat T140. when you travel with the machine over half speed it bogs the motor down almost to an idle. about half stick or less is OK. working hydraulics is ok. RPM is 2900 no load, has good fuel/fuel pressure, no restrictions, new lift pump. When the machine is bogged down the fuel rack pin is at about 60-75% (I took the buffer adjusting screw out so I could monitor/manipulate the rack pin) if I push on the pin past this point giving it more fuel as the governor should be doing It picks up speed. Any ideas? Something i am over looking? Thanks
Assuming its a non-turbo V2203 tier 2 the governor has two springs one inside the other for the governor control and one may be broken. The issue could be related to the balls on the cam plate but because your max RPM is close to where it should be I would be looking at the springs. I am not as familiar with the newer turbo tier 4 engines.
Here is a pic maybe that will help.
have you changed the fuel filter? :drinkup
Your hydro pump belt may be slipping. Had a S130 that did the same thing and all it needed was the belt tightened. Now that I think about it...maybe the engine didn't bog, just the hydro's did. Sorry.
Thanks frogfarmer. It is a V2203 tier2 with that set up. but the springs look fine. Aside from pulling the front cover off and inspecting the rest of the governor, im not sure what else to do with it, and it this time I dont think that is warranted. Other people mention that maybe its in the hydraulics but I dont think so, maybe if it was fueling near 100% I would think there might be a problem. the only time the rack goes to full fuel is when the key is on with the engine not running so I know its capable of doing so but under full load (or more than full load if the hydraulics are putting undue strain on the engine) It only fuels 75% at best as stated in my original question.
If you are certain the governor is not the culprit then start on the internals. What are the compression readings? Are the valves adjusted? Is there a restriction in the intake piping or the exhaust? Is the fuel quality good?
I do think the governor is the culprit. i just dont understand how enough to warrant pulling the front of the engine apart and possibly pulling the motor out to access. aside from a broken spring what could be wrong with the governor that would allow full no load RPM but not adding fuel as the rpm decreases( not a fuel or fuel pressure issue) just the governor is holding back the rack from increasing. I have pushed manually on the rack as an operator ran the machine and it WILL hold RPM under load. IE the motor is capable of producing power.
I understand your situation. I have turned up several engines and modified governors for years. There are a lot of parts to wear or come loose but as a general rule they don't. When something does come loose they can act quite funny. I do suspect a spring is the culprit. If the springs do not apply enough pressure to the reaction arm the fly balls are able to limit fuel and stay at their outer limit providing no increase in fuel because they cant feel the load. Because the engine is able to make power with you actuating the rack the engine it self should be good. The balls that act as fly weights can be varied to adjust reaction to load as well as the springs. Governors are very precisely tuned for each application and small changes make big differences in power output.
On a different train of thought does the fuel solenoid fully open to allow the pump to operate? If it were still applying just a small amount of pressure it would affect the operation and power output. Eliminate the fuel solenoid and see what happens.