Bobcat 610 lots of fuel in the oil...

[Bpu699]

Bobcat 610, spent the last year or so fixing it up... runs great... Everytime I dump the engine oil it looks like chocolate milk and smells like gas... This happens after only 30 minutes of use, as I checked the oil right after changing it... No radiator, so I know it isn't coolant...it's fuel. Looked at the car, float wasn't sealing, so rebuilt it... fixed nothing. Has electric fuel pump, 3-4 psi. If I drain the oil it's watery, let it sit in the pan for a day, returns to oil consistency as gas evaporates... Odd thing is, my oil NEVER gets hot. After running 20 minutes, I dump the oil, it's Luke warm. I can easily stick my finger in it. It's like the oil never gets hot enough to burn any fuel off... I know the oil pump works, as the line go the filter shoots oil when removed... All 4 cylinders work and have compression. I cylinder is burning oil as the plug is black/oily. I can see some oil getting past this cylinder... but that's a LOT of fuel in the oil... Any other ideas? Why isn't my oil getting hot? Do these engines really run this cold?

 

[foton]

if you are using the factory fuel pump the rubber diaphragm might have a pinhole in it , my Wisconsin 18 hp tdj had one just made a plate to cover hole put in a electric one 1.5 to 3.5 psi works great. no more oil issues.

 

[Bpu699]

if you are using the factory fuel pump the rubber diaphragm might have a pinhole in it , my Wisconsin 18 hp tdj had one just made a plate to cover hole put in a electric one 1.5 to 3.5 psi works great. no more oil issues.

Yep, its been replaced with a electric fuel pump... When you drain your oil... is it clear? Milky? Gas smell? Trying to figure out if this is "normal"?

 

[foton]

Yep, its been replaced with a electric fuel pump... When you drain your oil... is it clear? Milky? Gas smell? Trying to figure out if this is "normal"?

yes it did smell of gas and was thinned like water when oil was cold. do a compression check on the bad cylinder you need I think at least 80 psi to get some kind of ignition with a good spark. It might be just unburned fuel if it is not lighting up.

 

[Bpu699]

yes it did smell of gas and was thinned like water when oil was cold. do a compression check on the bad cylinder you need I think at least 80 psi to get some kind of ignition with a good spark. It might be just unburned fuel if it is not lighting up.

I'm sure compression is lower, but it does fire. If you remove the spark plug wire there is a clear difference... So are you saying your oil also was diluted with fuel? I've had lots of cars with a bad cylinder or 2... oil never looked like this after 30 minutes of use...

 

[foton]

I'm sure compression is lower, but it does fire. If you remove the spark plug wire there is a clear difference... So are you saying your oil also was diluted with fuel? I've had lots of cars with a bad cylinder or 2... oil never looked like this after 30 minutes of use...

yes when had bad fuel pump, but not the milkshake look though, that is typically water but you have a air cooled wisconsin right?

 

[Bpu699]

yes when had bad fuel pump, but not the milkshake look though, that is typically water but you have a air cooled wisconsin right?

Yep, air cooled... This weekend I'm going to mix some gas with the oil in a container and shake it up... I assume it will look like chocolate milk, just as it does with water... I'm at a loss, will do compression check soon, but this thing runs great...

 

[6brnorma]

Yep, air cooled... This weekend I'm going to mix some gas with the oil in a container and shake it up... I assume it will look like chocolate milk, just as it does with water... I'm at a loss, will do compression check soon, but this thing runs great...

Sorry…. I don't get to this site as often as I used to. Where do you store your machine when not in use? And where are you located? Also…. you might consider joining the FB site … Melroe Bobcat Owners of America …. Lots of knowledgeable folks that deal specially with these machines.