Last weekend I took my sled up in the mountains and it started up 1 pull let it warm up but one cylinder was dead I ran it anyways to see if it would clear up we go about half a mile down the trail and it started bogging really bad so bad I almost couldn't get it back to the truck. I shut it off checked the plug and it was soaking wet. I cleaned it pull it a few times and put it back together and then it wouldn't start. When I got home I pull the pipe off that cylinder and it had raw fuel in it enough to pour out. I checked my compression all is good, vacuum line is ok but my oil supply inlet on the pump had gas run out of it when I unhooked the oil supply hose. Is that normal and does anyone else have anything else that could cause this.
99 Yamaha mountain max 700 fuel pump issue.
- Thread starter Ewbaker95
- Start date
First mistake was running it with a dead cylinder.
remove all plugs, and pull recoil until all excess fuel is pumped out of the cylinders.
Install 3 new plugs and start sled, make sure it is running on all 3. If not shut off and diagnose.
remove all plugs, and pull recoil until all excess fuel is pumped out of the cylinders.
Install 3 new plugs and start sled, make sure it is running on all 3. If not shut off and diagnose.
- Thread starter
- #3
All three plugs are brand new not even one ride on then. I checked all the plugs, they all have spark. It's the center cylinder that I'm having this problem with. I believe now I'm have a bad seal between the needle and seat fouling the plug right away and allowing fuel into the exhaust pipe and even flowing out of the carb vent lines. But my question still is... Is there supposed to be gas aloud to flow out of the oil inlet nozzle on the fuel pump or not?
sounds like you may have a needle and seat issue in the carb, remove carbs clean, inspect, check float heights, and test the needle and seats to make sure they hold....I do this by flipping the carb upsidedown, hook my vacuum/pressure tester pump to the gas inlet and put pressure to the needle, see when it lifts off the seat and when it re-seats it should not leaks down......I hope that wasn't too confusing, it sounds good in my head lol
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- #5
If I'm not able to get my hands on a pressure gauge do too being away from home at the moment, I should be able to blow into the inlet on that carb being tested with light pressure and see if it holds with the carb upside down correct?
you can try that, it won't tell you if the needle is a slow leaker
- Thread starter
- #7
I'll try to rig something up. Do you have any idea if my fuel pump is having an issue or not?
- Thread starter
- #9
The fuel pump is pumping fuel and a good rate all threes lines. My vacuum line to the crank case has a strong pulse but when I unhooked my oil supply line gas came flowing out and a steady rate. Is that normal?
that can happen, the oil pump makes some pressure to overcome the gas pump pressure to ensure oil makes it into the mixing bowl in the pump, and when you pulled the oil line off gas was siphoning from the tank, no biggie
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- #11
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