Viper not pumping fuel

J

jaydougempire

Guest
Got the viper back together last night. And now it won't pump fuel. Tried pulling it like 100 times. There's fuel in the lines but it's not pumping to the carbs. Like its seeping into line and sitting there. I pulled the pulse line off and it seems fine. Blew some carb cleaner in the line and pulse hole. Pulled apart and cleaned fuel pump. Any other ideas before I put it back together? I squirted a small amount of fuel in the cylinder and it fires first pull...
 

The 2002 Vipers had an issue with the pump freezing in the vent hole on the bottom but if your pump is not out in the cold that wouldn't be the problem.
Ensure you have at least 1/2 tank of fuel.
Make sure your lines are all in the proper place on the pump
Pull a fuel line to one of the carbs off and try it to see if it pumps any fuel at all.
If there is still no fuel being pumped it sounds like you need a pump.
As far as I know there are no rebuild kits for SRX/Viper pumps.
I have had better luck with the 700SX[red head] pumps on my SRX.
 
sideshowBob said:
The 2002 Vipers had an issue with the pump freezing in the vent hole on the bottom but if your pump is not out in the cold that wouldn't be the problem.
Ensure you have at least 1/2 tank of fuel.
Make sure your lines are all in the proper place on the pump
Pull a fuel line to one of the carbs off and try it to see if it pumps any fuel at all.
If there is still no fuel being pumped it sounds like you need a pump.
As far as I know there are no rebuild kits for SRX/Viper pumps.
I have had better luck with the 700SX[red head] pumps on my SRX.
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It was stored with a dry gas tank could this affect anything? Zero fuel in the tank since last year
 
Update
Has strong spark
Pulse line is pulsing strong
 
When the system is dry it takes quite a bit to start that first time. I would try putting a cap of premix in each cylinder and pull over. It may take 3-4 times before the fuel is back through the whole system and is able to keep running. And like bob said at least a good 1/2 tank or more of gas. If its pulsing and you got spark it just needs time.
 
super1c said:
When the system is dry it takes quite a bit to start that first time. I would try putting a cap of premix in each cylinder and pull over. It may take 3-4 times before the fuel is back through the whole system and is able to keep running. And like bob said at least a good 1/2 tank or more of gas. If its pulsing and you got spark it just needs time.
Click to expand...

k I'll try that a few times and I'll put more gas in...With my Polaris I used to charge the fuel tank with air through the vent in the cap and found it helped push the fuel through the system...this gas cap doesn't have a vent hole. Is there a vent in the tank somewhere? Is it possible the line in the tank came of for something else in the tank?
 
Nope. I haven't. Just checked the line in the tank. It's attached but no filter on the end. Got to be the pump. I have pulse and spark and no restriction from tank...what else is there?
 
jaydougempire said:
Nope. I haven't. Just checked the line in the tank. It's attached but no filter on the end. Got to be the pump. I have pulse and spark and no restriction from tank...what else is there?
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If the filter is missing off the end of the pickup line then you'll either have to get another one to replace it with or weight the gas line down with something to keep the line down.You may just have an issue with the line not being below the fuel level.
 
fourbarrel said:
If the filter is missing off the end of the pickup line then you'll either have to get another one to replace it with or weight the gas line down with something to keep the line down.You may just have an issue with the line not being below the fuel level.
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There is a metal tube clamped to the rubber line in the tank...it's weighed down by that. Not floating. sorry for the crappy picture ImageUploadedByTapatalk1421026929.979711.jpg
 
K here's where im at. I found the vent line and charged the tank with compressed air. This primed the entire system. Filled pump and lines with fuel. Pulled mag carb line off the carb and pulled engine over and no pumpy pumpy...am I missing something here?
-Pulse is strong
-Spark is strong
-Tank is full with fresh premium
-Pump is clean and diaphragms are intact
-Nothing is frozen
-Pick up line is attached and at the bottom of the tank...

Should I just go get a new pump?? Does the pump require the engine running to draw enough pressure to pump fuel?? It should pump when turning over with pull cord correct?
 
If you know that the entire system is charged and it's not blocked by anything, and it's getting pulse, the pump is your problem.
 
Decent looking pulse lines have been known to collapse. I usually replace with black reinforced fuel line.
The old fuel lines might look good but have softened with age and collapse during the pulsing operation.
 
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roudyroy1 said:
If you know that the entire system is charged and it's not blocked by anything, and it's getting pulse, the pump is your problem.
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Alrighty pump it is! Sled has all new lines from yamaha so I think they are fine. I'll post back with results this week. Thanks fellas.
 
I asked that question last season and nobody knew of any kit available to rebuild a Yamaha fuel pump. They're not made by Mikuni so if it's the pump that's bad then the only option is to buy another one.
 
Found this pump...thinks it's from a 2001 SXR. Will it work on the viper? There's a vacuum line or something going from the fuel pump down to the oil pump. What is that line for.? This Mikuni pump doesn't have a inlet/outlet for it. ImageUploadedByTapatalk1421355124.803390.jpg
 
On the SRXs, Vipers, and tripple SXs and SXRs all have a very similar pump, the castings are the same shape.
That is not a three cylinder Yamaha pump in the picture and it will not plug and play!
The line to oil pump is there because that is how Yamaha supplies most of the oil to the engine. The oil pump, pumps oil into the fuel pump where it mixes with the fuel and then the fuel pump supplies the carbs premixed.
Stay with the Yamaha OEM pump, the SRXs and Viper pumps are the same part number and the SXR 700 is different but it will work also.
 
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