Engine smokes

[zippy2]

I have a Craftsman YT3000 lawn tractor with a 21 hp B&S engine. Shortly after changing the oil in April, the engine starting smoking. I may have overfilled the crankcase. Now I have to add oil after every cut. When cranking, a huge amount of black smoke blows out the exhaust. During mowing a small amount of bluish smoke is emitted. No trouble starting or mowing, except that I notice a decrease in power when encountering higher grass/weeds. Is it the carburetor or rings on the piston? How much is this going to cost to have a professional repair it? TIA

 

[Scrubcadet10]

Pull the oil dipstick and smell of it.... does it smell like gasoline?

 

[zippy2]

Pull the oil dipstick and smell of it.... does it smell like gasoline?

Yes.

 

[zippy2]

Pull the oil dipstick and smell of it.... does it smell like gasoline?

yes

 

[sgkent]

that appears to be your problem. The carb float is stuck and allowing gasoline to overfill the oil. It is destroying the engine. You cannot run the engine until you fix the cause of the fuel in the oil and change the oil again. Just changing the oil will not solve the cause. And it would be too expensive to change the oil each time you go to use the engine. If you are lucky you caught it in time. But there is already damage done to the engine.

What is happening is that the carb float is not shutting off fuel so it drips into the engine. Then it runs down into the oil making you think you overfilled it. Then when it starts it runs rough with black smoke as all the excess fuel burns. Next the thin oil washes past the rings and burns, making the engine smoke. In addition the thin oil is causing bearing damage, damage to the rings and cylinder walls, and valve guide damage.

 

[Scrubcadet10]

that appears to be your problem. The carb float is stuck and allowing gasoline to overfill the oil. It is destroying the engine. You cannot run the engine until you fix the cause of the fuel in the oil and change the oil again. Just changing the oil will not solve the cause. And it would be too expensive to change the oil each time you go to use the engine. If you are lucky you caught it in time. But there is already damage done to the engine.

What is happening is that the carb float is not shutting off fuel so it drips into the engine. Then it runs down into the oil making you think you overfilled it. Then when it starts it runs rough with black smoke as all the excess fuel burns. Next the thin oil washes past the rings and burns, making the engine smoke. In addition the thin oil is causing bearing damage, damage to the rings and cylinder walls, and valve guide damage.

^^^^^ what he said.

 

[zippy2]

that appears to be your problem. The carb float is stuck and allowing gasoline to overfill the oil. It is destroying the engine. You cannot run the engine until you fix the cause of the fuel in the oil and change the oil again. Just changing the oil will not solve the cause. And it would be too expensive to change the oil each time you go to use the engine. If you are lucky you caught it in time. But there is already damage done to the engine.

What is happening is that the carb float is not shutting off fuel so it drips into the engine. Then it runs down into the oil making you think you overfilled it. Then when it starts it runs rough with black smoke as all the excess fuel burns. Next the thin oil washes past the rings and burns, making the engine smoke. In addition the thin oil is causing bearing damage, damage to the rings and cylinder walls, and valve guide damage.

Thanks for your reply. I have taken the carb off, but I can't get the screws off the bowl to inspect. Apparently a replacement carb is not available, only a tuneup kit. Advice?

 

[bertsmobile1]

The 2 screw Nikki bowl screws strike again
Put the carb in a vice making sure you protect the flanges .
I use old inner tubes
Then with a power driver bit held by a 1/4" spannar push down hard on the end of the bit while turning the spanner
They are a PIA to remove
And they are a Posi-Drive head No 2 not a Phillips .

 

[zippy2]

The 2 screw Nikki bowl screws strike again
Put the carb in a vice making sure you protect the flanges .
I use old inner tubes
Then with a power driver bit held by a 1/4" spannar push down hard on the end of the bit while turning the spanner
They are a PIA to remove
And they are a Posi-Drive head No 2 not a Phillips .

Thanks for advice! I fiddled around with the screws and got them off after trying to use a phillips head (oops!). Think I've found a total replacement on ebay. Will see.....

 

[OzPete]

I have a Craftsman YT3000 lawn tractor with a 21 hp B&S engine. Shortly after changing the oil in April, the engine starting smoking. I may have overfilled the crankcase. Now I have to add oil after every cut. When cranking, a huge amount of black smoke blows out the exhaust. During mowing a small amount of bluish smoke is emitted. No trouble starting or mowing, except that I notice a decrease in power when encountering higher grass/weeds. Is it the carburetor or rings on the piston? How much is this going to cost to have a professional repair it? TIA

Your engine has a blown head gasket.
Nothing to do with having had an oil change .. it's a single cylinder overhead valve B&S engine, so it was ALWAYS gonna get a blown head gasket.
They ALL do.
Your local B&S dealer's Service Manager will know exactly how much it will cost to fix coz it's such a common problem.