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Discussion Starter · #1 ·
I rode my sled the other day and it ran great. I rode it into the garage then shut it off and all was fine. Today I went to start it and I could not get it to even attempt to start. This sled alway starts on the second pull. I see some wetness in the clutch area that looks like the crank was slinging around some oil/fuel. Could the seal have blown out while riding it and let it stay running and not show up as a problem until next start or is it more likely that it blew out while I was trying to start it? Does this even sound like a crank seal problem?....I have not ran across this before. If it is the seal, is it a sign something else is bad or is this more of a "it happens sooner or later" thing? I know its a lot of questions, thanks for the help.
--Ron
 

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Well it could be a bad seal. I would take a look at the spark and then go from there. How does the plugs look? Make sure that the sled is not flooded. Were you having any issues with bad performance when you riding before you put it away? I would look at the seals on the clutch side of the motor. You are going to have to take the primary off to look at the seal. Cheap to replace but hard to do the replace. It took me about 2-3 hours to rebuild my motor after it was out of my sled. If you don't know how to do this I would have someone that does know how to. You just don't want any thing in the motor or put together wrong.
 

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Discussion Starter · #3 ·
The sled ran great before i shut it off....no signs of poor performance. The spark is good and the plugs are getting fuel. If I put in a new set of plugs it will make about a 1 second attempt to fire and that is all and it only does it once. I am suspecting the seal since I see the oil slung around under the hood from the crank area. Are these seals replaceable once the clutch is off or is there engine disassembly required? This is the Fuji 500 engine.
 

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to replace the crankseal you have to completely disassemble the engine.
id verify youre problem before tearing down. im not saying crank seal aint bad specially if youre seeing fluid. but even with a bad sel it should still fire up. im thinking as early questioned youre flooding??
needle and seats maybe went bad. try draining cylinders. id just hate to see you replace the crank seal and still have a problem. plus thats a complete engine teardown.
 

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You can replace the crank seals without splitting the case, but I would not recommend doing it that way, they might blow out. Do it the right way and split the case. If the pulse line hooks up to that crankcase, your fuel pump probably isn't working, hence the reason why it won't run.
 

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Discussion Starter · #6 ·
It is definetly the crank seal. I wiped it dry and turned the clutch by hand and was able to see the fuel spraying/coming out. Has anyone replaced the seal with success without motor disassembly? It is near the end of the season and I was wondering if I can just remove and install it from the outside in hopes to get by for maybe one more local trail ride then do a disassembly during off-season.
 

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I would still look for other problems. My 440 liq has been throwing fluids around the whole engine bay for 10 years or more, its a 92', and it runs quite well, too well for an engine rebuild.

Does it run and burn a prime down the cylinders? The engine may be totally flooded because of another issue; and to see fluids spewing out by turning the clutch doesn't sound good, seal bad or not.
 

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if you turned the clutch by hand and can see fuel spray coming out, you have more problems then that. i would definately lok for other problems. a simple and cheap fix will onl cost you in the long run!!!!!
imagine how lil fuel mixture is sprayed through the cylinders eac time your egine turns,
also thnk about how much or how lil vapor comes out the plug hole when you pull the sled over with no plug in it.
now to have fuel coming out the crankseal by simply turn the clutch by hand?!
cylinders were probally flooded!!! good possibility needle and seats.
im only trying to help, a quick cheap fix can and will burn you!!!
im sure others will agree
 

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bigwedgies has it,needles and seats are stuck filling the crankcase up with fuel

As someone stated above pull the plugs on the bottom of the cylinders under the y pipe and watch the fuel poor out. Before you do this shut the fuel off. If you get alot of fuel then order the new needles and seats (viton)Leave the fuel off for a day and then go try and start it(you will need to turn the fuel on)....it should start up and you could potentially ride it as long as you remember to shut the fuel off whenever you stop. If you forget ,,,,your walking

I had a Indy 500 with a bad crank seal.....It would run only for a short time and shut down...that is not your problem. If the seal is bad there will be no or limited vacume to make the pump work....As the machine sets fuel will trickle into the carb, usually enough to start the sled but then it runs out of fuel.
 

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Discussion Starter · #10 ·
BINGO!!!, thanks for all your advice guys. Sure enough I pulled the 2 plugs on the front of the block and a river of fuel came out. I let it set overnight and put the block plugs and the spark plugs back in, pulled the rope and it fired up first pull. I am running out of snow so I have just been riding around the yard then turning the fuel off when I shut it down and all has been fine. When the weather warms up I will R&R and clean the carbs out. Thanks again for all the help.....It saved me time and aggravation and what really bothers me is that I should have realized that when I saw fuel coming from the crank seal that it should not have been there in the first place being a 2-stroke.
--Ron
 

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We've been there, done that, bought the t-shirt


Make sure you change the needles and seats. Cleaning prob. will not help....Buy viton they are around 20 a piece
 
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