743B smoking

[oracle_of_ferndale]

This is an early-1990s 743B with a re-purposed V2203 refrigeration engine. Just finished replacing the hose running from the oil cooler to the filter. Re-filled hydraulic fluid and antifreeze (I pulled the radiator to get to the oil cooler). The machine had been stuck in the mud recently, so I sprayed out the bottom of the engine compartment. When I start the engine, white smoke pours out of the exhaust. The engine sounds rough too. It has been losing a little oil, but I can't tell if it is burning or leaking. The repurposed V2203 makes it a bit strange - air intake points behind the machine and there is a vacuum line between the intake and the head cover (original V1702 did not have these). Where should I start looking for problems? If water got in the air intake, would that cause the white smoke? I appreciate any suggestions.

 

[Bobcatdan]

My guess is water in your fuel.

 

[oracle_of_ferndale]

My guess is water in your fuel.

Thank you Bobcatdan. Is this going to cause bigger problems, or can I clear the fuel line and let it run through?

 

[oracle_of_ferndale]

Thank you Bobcatdan. Is this going to cause bigger problems, or can I clear the fuel line and let it run through?

I purged some of the fuel from the fuel line and did not notice any water. Started the machine and now thick black smoke and just barely running. Shut it down and checked the oil. It had gone from new to black in about a minute. I suspect this is a bigger problem. Could it be a simple head gasket, or am I looking at another new engine? Something else? What to check first? Suggestions appreciated. Thanks. https://www.dropbox.com/s/d17327l3gef80bf/Bobcatsmoke.JPG?dl=0

 

[Tazza]

I purged some of the fuel from the fuel line and did not notice any water. Started the machine and now thick black smoke and just barely running. Shut it down and checked the oil. It had gone from new to black in about a minute. I suspect this is a bigger problem. Could it be a simple head gasket, or am I looking at another new engine? Something else? What to check first? Suggestions appreciated. Thanks. https://www.dropbox.com/s/d17327l3gef80bf/Bobcatsmoke.JPG?dl=0

I assume it ran fine before it got stuck?
Did you change or clean the air filter?

 

[oracle_of_ferndale]

I assume it ran fine before it got stuck?
Did you change or clean the air filter?

Thank you Taz - It ran fine before and after it was stuck. Only problem was a hydraulic leak. I think the air filter is okay, but it still might not be getting enough air. The hose I rigged up does not fit well with the new motor. Involves half a roll of duct tape and gets narrow around a corner... Could that be the problem?

 

[mark18mwm]

Thank you Taz - It ran fine before and after it was stuck. Only problem was a hydraulic leak. I think the air filter is okay, but it still might not be getting enough air. The hose I rigged up does not fit well with the new motor. Involves half a roll of duct tape and gets narrow around a corner... Could that be the problem?

You mentioned a modified air intake and you washed the machine. Any chance you got water into the intake/ air cleaner? The withe smoke may have been steam from the water going into the engine and going out the exhaust, now the black smoke leads me to believe the air filter is now plugged from being wet and "choking" the engine. Just my best guess.

 

[Tazza]

You mentioned a modified air intake and you washed the machine. Any chance you got water into the intake/ air cleaner? The withe smoke may have been steam from the water going into the engine and going out the exhaust, now the black smoke leads me to believe the air filter is now plugged from being wet and "choking" the engine. Just my best guess.

It's worth checking, if it's sucking flat it will smoke and be hard to keep running.
I'm with Mark, if the air filter is plugged, it will smoke like crazy because it's being choked.

 

[oracle_of_ferndale]

It's worth checking, if it's sucking flat it will smoke and be hard to keep running.
I'm with Mark, if the air filter is plugged, it will smoke like crazy because it's being choked.

Sure enough there was a kink in the air hose. Straightened it out and no more black smoke. Ran it for about ten minutes and it sprung a new hydraulic leak... Who needs a hobby when you have an old bobcat?

 

[Tazza]

Sure enough there was a kink in the air hose. Straightened it out and no more black smoke. Ran it for about ten minutes and it sprung a new hydraulic leak... Who needs a hobby when you have an old bobcat?

Glad it was simple.
Sadly it happens with old hoses, not a lot you can do.
If you spot any with cracks, it may be time to swap them out too.

 

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Glad it was simple.
Sadly it happens with old hoses, not a lot you can do.
If you spot any with cracks, it may be time to swap them out too.

pretty sure diesel engines turn the oil black almost immediately, so i wouldn't worry about that