610 mule with fuel problems

texas_outlaw82 · 07-04-2009

new to this forum so hi everybody! ive got a problem with my 610 mule 4x4. i can usually fix small engines but this one has me stumped! im getting gas in my oil, smoking blue, pushing fuel out of the top of the fuel pump, i pulled the carb off and it looks great. only has 21 hours on it! any help would be great!

RCW · 07-04-2009

The fuel pump is a pulse actuated diaphragm. I would suspect the diaphragm has cracked and you are pumping gasoline into the engine through the tube that provides the pulse to the fuel pump.

The blue smoke is the thinned oil slipping past the oil control ring if my assessment is correct.

Easy fix, replace the fuel pump and change the oil.

texas_outlaw82 · 07-04-2009

well i put a new fuel pump on it and my problem is still there. its pushing oil and gas im guessing out of the crankcase and filling up the separator and pushing it back into the fuel pump and out the vent on the pump. i thought it may have too much crankcase pressure and its pushing it out where it can? is there another crankcase vent that may be stopped up? i figured that tube would pull vacuum instead of push?

RCW · 07-04-2009

I have never seen a vent on the top of the fuel pump on the 610, it is sealed and operates from crankcase pulses. If you trace the hose out of the curved fitting on top of the pump it will go through an oil separator and then down to the crankcase. If that system is not sealed at the pump you have a major defect in the pump.

Take a clean chunk of hose, connect it to the top curved fitting, and blow. If the air goes anywhere the pump is shot!

There is a sealed Crankcase Ventilation System that is not really serviceable, as there is nothing to break as long as the hoses still have their integrity. You can follow the small hose from the top of the inlet elbow on the air cleaner side of the carburetor air inlet and check that quite easily.

If someone ran the Mule with a cracked fuel pump diaphragm they may well have contaminated the oil enough to cause one or more of the compression rings to seize to the piston. That will then generate so much blow-by that it will pump oil to the point of not being usable. If that is the case, do a compression test.

texas_outlaw82 · 07-05-2009

thanx, i got it fixed, yeah kinda did some thinking and yeah kinda feel stupid! lol i understand now, only problem is the dammn thing wont quit smoking. is it going to do that until i burn all that gas and oil out of the exhaust? when i did the oil change there was a ton of fuel in it. think it may have done some damage?

RCW · 07-06-2009

Never feel stupid. Simple problems like fuel in the oil can lead to all sorts of complexities that have to be checked and ruled out.

Only a compression test will tell you if there is permanent engine damage. But, as long as the oil was not diluted enough to run like water it is doubtful there is permanent damage.

You will want to adjust your valves after the contaminated oil has been drained and it has fresh oil.

texas_outlaw82 · 07-07-2009

kewl, thanx, do you know if there is a thread on her about how to adjust the valves? and yes the oil was like water

07-04-2009	#1 (permalink)
texas_outlaw82 Newbie Join Date: Jul 2009 Posts: 4	610 mule with fuel problems new to this forum so hi everybody! ive got a problem with my 610 mule 4x4. i can usually fix small engines but this one has me stumped! im getting gas in my oil, smoking blue, pushing fuel out of the top of the fuel pump, i pulled the carb off and it looks great. only has 21 hours on it! any help would be great!

07-04-2009	#2 (permalink)
RCW Way Too Much Free Time BTK Expert Join Date: Nov 2007 Location: Oregon, Chile, Alberta, Texas Posts: 1,481	The fuel pump is a pulse actuated diaphragm. I would suspect the diaphragm has cracked and you are pumping gasoline into the engine through the tube that provides the pulse to the fuel pump. The blue smoke is the thinned oil slipping past the oil control ring if my assessment is correct. Easy fix, replace the fuel pump and change the oil. __________________ 2008 3010 Trans4X4 Diesel Mule 2008 JD XUV 850 Diesel 1979 XS650 Yamaha New DR-Z400S

07-04-2009	#4 (permalink)
RCW Way Too Much Free Time BTK Expert Join Date: Nov 2007 Location: Oregon, Chile, Alberta, Texas Posts: 1,481	I have never seen a vent on the top of the fuel pump on the 610, it is sealed and operates from crankcase pulses. If you trace the hose out of the curved fitting on top of the pump it will go through an oil separator and then down to the crankcase. If that system is not sealed at the pump you have a major defect in the pump. Take a clean chunk of hose, connect it to the top curved fitting, and blow. If the air goes anywhere the pump is shot! There is a sealed Crankcase Ventilation System that is not really serviceable, as there is nothing to break as long as the hoses still have their integrity. You can follow the small hose from the top of the inlet elbow on the air cleaner side of the carburetor air inlet and check that quite easily. If someone ran the Mule with a cracked fuel pump diaphragm they may well have contaminated the oil enough to cause one or more of the compression rings to seize to the piston. That will then generate so much blow-by that it will pump oil to the point of not being usable. If that is the case, do a compression test. __________________ 2008 3010 Trans4X4 Diesel Mule 2008 JD XUV 850 Diesel 1979 XS650 Yamaha New DR-Z400S

07-06-2009	#6 (permalink)
RCW Way Too Much Free Time BTK Expert Join Date: Nov 2007 Location: Oregon, Chile, Alberta, Texas Posts: 1,481	Never feel stupid. Simple problems like fuel in the oil can lead to all sorts of complexities that have to be checked and ruled out. Only a compression test will tell you if there is permanent engine damage. But, as long as the oil was not diluted enough to run like water it is doubtful there is permanent damage. You will want to adjust your valves after the contaminated oil has been drained and it has fresh oil. __________________ 2008 3010 Trans4X4 Diesel Mule 2008 JD XUV 850 Diesel 1979 XS650 Yamaha New DR-Z400S

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07-04-2009	#3 (permalink)
texas_outlaw82 Newbie Join Date: Jul 2009 Posts: 4	well i put a new fuel pump on it and my problem is still there. its pushing oil and gas im guessing out of the crankcase and filling up the separator and pushing it back into the fuel pump and out the vent on the pump. i thought it may have too much crankcase pressure and its pushing it out where it can? is there another crankcase vent that may be stopped up? i figured that tube would pull vacuum instead of push?

07-05-2009	#5 (permalink)
texas_outlaw82 Newbie Join Date: Jul 2009 Posts: 4	thanx, i got it fixed, yeah kinda did some thinking and yeah kinda feel stupid! lol i understand now, only problem is the dammn thing wont quit smoking. is it going to do that until i burn all that gas and oil out of the exhaust? when i did the oil change there was a ton of fuel in it. think it may have done some damage?

07-07-2009	#7 (permalink)
texas_outlaw82 Newbie Join Date: Jul 2009 Posts: 4	kewl, thanx, do you know if there is a thread on her about how to adjust the valves? and yes the oil was like water

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