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Discussion Starter #1
I have a 96 sportsman 400 4x4 it been inside setting 2 years , I cleaned the fuel system and carb, fired it up and started smoking excessively, it begin blowing oil out the air pipe for the drive clutch housing, I removed cover it was full of oil and tank was empty, I have started it with pre mix 40:1 seems to run ok , any Ideas.
RANDY
 

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Could have filled the crank case and was pushed out the crank seal. Does that engine have a drain plug on the bottom half? After draining it out start it up and spray carb cleaner or starting fluid around the crank seal behind the clutch and see if the Rpms change, that indicates a bad crank seal.
 

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Welcome to the board!
 

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Discussion Starter #4
Don't see a drain plug, It is a 2 stroke , I have removed the drive clutch, seal is in place can you run the engine without a drive clutch checking for a leak.
 

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You can run it with out the clutch but be careful not to rev it hard cecause there isnt any resistance. Also might not idle for crap without it because there is less mass.

There should be a case drain, in case it gets filled with gas or oil.
 

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Discussion Starter #6
Thanks for the reply's been a while getting back to this I Pulled the drive clutch sprayed carb cleaner and engine starting fluid on crank shaft at seal no change in engine rpm's? so I put it back together have rode it 5-10 miles seems ok has not lost any more oil, seems to smoke more than I remember at WOT . I didn't pay that close attention before any chance setting 2+ years the oil could drain from the tank into the engine with nothing wrong? this thing has 4500 plus miles on it .
 

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The oil has to go through the oil pump. Filling the engine indicates the pump is bad. Normally when they go they fail in that manner and allow full flow of oil all the time.
 

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Discussion Starter #8
The oil went from the tank to engine without it being running it was just setting a couple years , I was under the assumption the barrel fitting between the pump and engine is a pressure valve I have not removed it and pressure tested it. this all started when the drive belt are filled with oil does a oil pump failure do this or is there an adjustment on the pump or possibly a bad pressure valve.
 

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There is a check valve that only allows oil to flow one way or the pump can back flow it into the tank. If the oil is getting by the pump just sitting, the seals inside the pump are bad and letting the oil flow through it without running/turning. The extra smoke is evidence that the pump s bad too as it's basically at full flow al the time so it's pumping way more oil than it should. The pumps on those machines are known to be faulty on a regular basis. It was the only real thing on them that was a big problem. The fact that the clutch housing got filled up too means you probably have a crank seal that is bad or on it's way out.
 

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Discussion Starter #10
Understood, I also have a new pump to install, is there another check valve besides the one on the pressure or discharge side the only one I have found is a barrel type that bolts to the engine .do you think the entire content's could drain into the engine over a period of time and when I started it pushed it all out the crank seal , since the first fire up from setting it has not pushed any more oil into the clutch/belt housing, and the oil tank level still full but I haven't rode 5-10 miles. I will try the pump the smoke is at wide open throttle 50-60mph?
 
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