Snowmobile World banner

Starting Issue After Drain Crank

1933 Views 12 Replies 5 Participants Last post by  craig14122
So two days ago i drained the crank because i was hold it would help because the sled wasnt running good, it was bogging down and you couldnt floor it. Anyways as you can see in teh pictures that some black some is coming out the seal and i no the drain plugs arent there because i took them out. I put them in before i started it. But it ownt start it just keeps flooding the plugs. And wehre the manifold meets the muffler there is some black stuff that smells like gas. And the tilt of the trailer dont seem that bad. Also the cup had a little bit more in the other parts of crank and this was after 2 days.Any ideas?


See less See more
1 - 13 of 13 Posts
If it were mine, I'd make sure the spark and compression were ok, then I'd pull the
exhaust off to look for fluid or anything that might be an obstruction [like a mouse nest]
then I would pull the carbs apart and check float levels and inlet needles. I think that a lot of flooding problems that we are starting to see may be related to warming temps, fuel
expanding, tank vent lines plugged, float levels marginal and so on. check em all.
I know the fuel is good and its around 28 degrees out. The tank vent lines are plugged but i havent checked the float levels. Do i have to take teh carb off to check them? I'm ok good with engines not as good with the carbs. So do you think some1 who has owned a sled for about7 years could do it with an ok amout of experience?
make sure you check the line from the engine block to the fuel pump to see if there is gas in it.could be flooding the block
shouldn't there be gas in that?
No, it might be wet but no liquid fuel. the motor pumps air[which has fuel mixed with it] back and forth into the block hose to power the the pump. lots of fuel in the line would indicate a ruptured fuel pump diaphram and flooding symptoms.
i will check that thank you
If the crankcase was full of fuel, then you have a problem with your carbs. Normally I would guess that you h ave a bad needle and seat. They do go bad from time to time.

Also, I noticed that you said your vent lines are blocked off. Those need to be open in order for the tank to breathe. If they are plugged then the tank builds pressure as the day warms after a cold night. When the pressure builds, it becomes more likely that fuel will be pushed past the needle and seat and end up flooding the case.
IDK why i rote they were plugged up but they arent. Also how much would it cost for the needle and seats? And could i do it myself? How do i check if they are bad?
IDK why i rote they were plugged up but they arent. Also how much would it cost for the needle and seats? And could i do it myself? How do i check if they are bad?[/b]
They are not a high cost item. If you are getting your crankcase filled with fuel, then you just need to do it. You can do it yourself. It's very easy.
But dont you think it would be the fuel pump because all 3 are filling up with gas. So all three needles and seats would be gone. Also which one on the fuel pump goes to the crank?


See less See more
It looks like it would be the one on the bottom. The fuel line from the tank and the three outlet lines to the carbs all have barbs on the same side of a diaphragm. The impulse line from the crank is on the "dry" side of a diaphragm.

AS for fuel under all three cylinders, the case is all one space with individual case sections separated from each other only by what is called a labyrinth seal. Those seals amount to nothing more than a section on the crank with grooves cut in it the tops of which near touch a very closely machined section in the case halves. This slows the fuel mixture in a given crank section from being pushed into an adjacent section. When the engines runs, it works quite well assuming the bearings are in decent shape with near zero play. When the machine is shut down, the pressures in all sections equalizes soon after motion stops just as the compression in the cylinders also equalizes to atmospheric as the machine sits. If you have an inlet needle or seat which is leaking, it will fill one case section until it reaches the height of the labyrinth seal and then spill over into the next section(s). THat is why you may drain all three sections and find gas in them even with only one bad needle/seat. The easy way to see if or which carb is causing the problem would be to leave the drains open and look to see which one drips. If it is the same case section from which the impulse is connected, you can't be sure it isn't the pump without removing the impulse line. If fuel is leaking through the impulse line, then you know it's the pump.

The newer machines use a needle in the fuel inlet with a synthetic tip, unlike the older ones which had a plates brass tip which would eventually wear. Leaking needles and seats are no longer common. Foreign material getting caught between them isn't unheard of however. Figure out the source of your problem and correct it. If stray material in the fuel inlets is a problem, make sure you check/change your fuel filter. Replacing fuel lines wouldn't be a bad idea either as they will deteriorate with time.
See less See more
ok where are the needle and seats in the carbs? I found the problem and its not the pump its the middle carb and the left carb is draining some too. So how much is it gonna cost and is it easy to do?
1 - 13 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.