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Discussion Starter #1
Hello Gentlemen,

1989 Ski Doo Citation Safari 250 rotax! I've tinkered with this amazing little sled for years and it's hardly let me down, I recommend one to anybody who just wants to get around ANYWHERE easily in the bush (not crazy mountain powder).

It's starving for fuel after a couple minutes. I can see the pump working, and fuel entering the carb, then suddenly it runs dry and engine dies. Would the fuel pump quit like this? after showing it's pumping? I just cant see anything wrong. One thing to note: I removed the primer because I broke the "T" fitting, so the fuel runs straight to the pump, no T. The primer line to the carb is plugged but still connected. I prime it by pouring a little fuel into the top of the carb. The other recent change is plugging the oil injection line at the throttle since I run pre mixed gas and I need the coupler after breaking the T. I dont know how either of these things could be an issue effecting the gas delivery, but mentioning it anyway. THe fuel pump was rebuilt a few years ago, maybe 3. I topped up the fuel tank. The only other thing is just before it started behaving this way, I went UP and the DOWN a really steep bank. I thought maybe the gas line from the tank went dry, but I ruled that out with filling the tank and starting the sled several times. Once I restart it after it runs dry, I can see the pump working well from what I can tell, since fuel runs pretty quickly up from the pump, filling the line to the carb. Any ideas??? Any help is appreciated. Can the pump function momentarily and then quit because its actually faulty? Or crankcase vacuum issue? THANKS!
 

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Fuel tank vent plugged?
 

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Discussion Starter #3
Hey thanks for the suggestion. I was thinking I'd look more into it in the morning yes. The vent looked clear to the eye. I'll try blowing in it, and the fuel pick up as well, maybe the filter is clogged and releases the debris after it sits a few min, and then sucks it back up. Do you think a fuel pump could be failing but work enough for a minute? Oh this small engine troubleshooting...
 

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Discussion Starter #5
Hmm, I don't think it's that, since it starves for fuel from the pump. I can see in the line that fuel suddenly stops flowing into the carb. I need to plow snow this am but I'll try further and get back this afternoon.
 

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Pull the carb go threw the pilot passages and test that the float shuts of just as it becomes 'Level'.
With a piece of fuel line attached, blow into it and raise the float with other hand until you cant pass air, this is where your float is set, make it 'Level' with carb body
 

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Discussion Starter #7
Thanks for this, that's great advice. I haven't touched it since I posted, we're busy getting buried in snow in central BC.
 

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Discussion Starter #8
Hello again finally gentlemen. Thanks for all the help offered, and for your patience, we've had back to back snow storms since Xmas. -32 here now! I got the sled running well again. But I really can't figure out what did it! I replaced the gaskets and diaphragm in the fuel pump, took the carb apart, checked all the fuel lines, and tank pick up. Couldn't find a thing wrong. My best guess is either the fuel pump gasket was worn and leaking air, or the floats were stuck or off-kilter, but I couldn't tell when I pulled the bowl off. I know sometimes if you just take a carb apart and put it back together, it works! Tiny pieces of debris etc, who knows. It looked pretty clean. Taking it for a longer test drive tomorrow.
 

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Discussion Starter #12
Thanks, that makes sense. I didn't see anything obvious, but maybe they're Insider the pump housing. Anyhow, it's not fixed after all! It ran a lot longer, but failed again. I still haven't found an answer to whether the pump fuel line to the carb is always primed, or if the carb/float regulates that.

The engine just dies suddenly, and the fuel inlet line at the carb loses fuel. I thought this would be a pump issue, so either I missed an issue with the check valves, or the floats are sticky or something. I'll keep tinkering... -39 here today!
 
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