This is likely a question that has been covered here before, but i'll ask it anyway. Has anyone done either fuel pump mods shown in the tech section? Which would you recomend? if any? Anyone had their pump freeze? 
I would just shim the pump up off of the tunnel approx 1/4"-5/16" with washers or rubber spacers. Then a little dab of locktite on the nuts. Raising the pump up off of the tunnel, prevents the pump from sitting in water, sucking in that water, then freezing.
If the motor is stock, you could plug the hole with silicone. But I perfer not to, since raising the pump will fix the problem.
If the sled is piped, I would NOT plug the hole. Due to the risk of possibly reducing the max fuel flow of the pump.
Modifed motors with large jets require good reliable fuel flow from the pump!
If the motor is stock, you could plug the hole with silicone. But I perfer not to, since raising the pump will fix the problem.
If the sled is piped, I would NOT plug the hole. Due to the risk of possibly reducing the max fuel flow of the pump.
Modifed motors with large jets require good reliable fuel flow from the pump!
mopar1rules
Active member
I put a hauck venom kit on my 2002 viper and raised the fuel pump by placing 1 washer under each mounting bolt and I plugged the hole with some silicone. Am I going to be finding myself in some hot water down the trail? Hauck told me to do it according to the instructions that came with the kit. Should I go off of hauck's recommendations or pull out the silicone?
Not sure what the venom kit is, however if it's piped you may want to pull the silicone out.mopar1rules said:
The reason to hole is there is to vent the back side of the diaphram in the pump. As the pump diaphram pulses back and forth, it creates pressure/vacuum on the back side. The hole allows this pressure/vacuum to escape. If the hole is plugged, it is possible that the trapped air can dampen the diaphram movement. Which in turn could reduce the pumps maximum flow rating.
Is it enough to make a difference? On a stock engine, shouldn't be an issue.
Modifed engines with larger main jets, require plenty of fuel flow from the pump to maintain a proper fuel levels in the carb at WOT. So on a modified sled it "could" cause a lean condition on a long WOT pull.
Thats why I just shim the pump. Fixes the freeze problem, with out adding another possible source of burn down.
You may want to add some more washers, for a little more air gap though!
mopar1rules
Active member
Mtnviper said, "If the sled is piped, I would NOT plug the hole. Due to the risk of possibly reducing the max fuel flow of the pump.
Modifed motors with large jets require good reliable fuel flow from the pump!"
I don't know if this would apply to me then, because my sled actually gets jetted leaner than stock, because you unplug the vent lines to the airbox, so the carbs are no longer vented. Stock jetting is 156.3 on all 3 cylinders and with the venom kit the pto and center are 148 and the mag is 150. Would it still apply to me though, because its still tripple piped, even though the main jets are smaller than stock?
Modifed motors with large jets require good reliable fuel flow from the pump!"
I don't know if this would apply to me then, because my sled actually gets jetted leaner than stock, because you unplug the vent lines to the airbox, so the carbs are no longer vented. Stock jetting is 156.3 on all 3 cylinders and with the venom kit the pto and center are 148 and the mag is 150. Would it still apply to me though, because its still tripple piped, even though the main jets are smaller than stock?
Unplugging the vent line from the air box effectively changes the air pressure in the float bowls. The pressure change, changes the fuel flow rate through the jet. Think of it in terms of raising or lowering the float level. Raising the float level will slightly increase fuel flow through the jet, by increasing the "bowl fuel pressure" exposed to the jet surface. Making it flow as if it is a larger jet size.
Your engine is going to require X amount of fuel,for a give,n amount of HP and load. Higher pressure/smaller jet, lower pressure/larger jet, (bowl pressure, not pump pressure) as long as the "total" fuel volume is the same, your motor will be happy. The difference between the 2 is mostly related to driveability/tuning issues.
Getting back to your sled, it is making more HP power then stock, then it's going to require more fuel. The smaller jets with the vent lines disconnected richen's the fuel mixture for you.
Because you are drawing the fuel out of the float bowl at a faster rate, the demand from the fuel pump becomes greater. In order to keep the float levels at the proper height during WOT conditions.
Your engine is going to require X amount of fuel,for a give,n amount of HP and load. Higher pressure/smaller jet, lower pressure/larger jet, (bowl pressure, not pump pressure) as long as the "total" fuel volume is the same, your motor will be happy. The difference between the 2 is mostly related to driveability/tuning issues.
Getting back to your sled, it is making more HP power then stock, then it's going to require more fuel. The smaller jets with the vent lines disconnected richen's the fuel mixture for you.
Because you are drawing the fuel out of the float bowl at a faster rate, the demand from the fuel pump becomes greater. In order to keep the float levels at the proper height during WOT conditions.
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rancidjo
New member
when I bought my 02 viper ER (new) the pump kept freezing up. I then shimmed it up...removed al the moisture out of the pump again...still froze up, I then put a dab of silicon on the vent hole...no more freezing...sled motor is stock
mopar1rules
Active member
Well, I pulled out the silicone on the vent hole this weekend. The fuel pump is still shimmed up 2 washers thick underneath each mount. I don't ride in deep powder, so I think that I shouldn't have a problem with it ever freezing up. I'm sure yamaha has that vent hole in there for a reason.