[dandeneaut]

I bought my '02 919 last fall. Guy dragged it out of his shed. "Never been dropped" Rrriiiigggghhhht!!! Changed all fluids. New air filter. The dead mice in the old one were problematic I think. Replaced all plugs. It has a PowerCommander 3 which I downloaded and installed the correct map for an '02 919 with a full 2 brothers exhaust. Runs fine for the first half hour then sputters, and stutters. Seems to get worse as the tank gets emptier. From reading other threads on this forum, I have decided it's the fuel pressure regulator. That is now on order. My question is should I drain the tank as much as possible when I replace the fpr, or just replace the fpr and see if that takes care of all the issues?

 

[beefsalad]

Does it smell like old shitty varnished gas? If so drain it.

 

[dandeneaut]

I've run several tanks of gas through it. So there is no varnished gas smell. Just wondering if the fact that it runs even worse with the low fuel level that draining it would be a good idea.

 

[beefsalad]

sounds like its worth pulling the pump to see what the filter looks like. when the manual says 6ftlbs for the pump, THEY MEAN IT! The studs are like swiss cheese

 

[7yroh6mech]

Do you hear the pump, does it sound strong?

 

[rufftup]

What beefsalad said.

 

[dandeneaut]

Changed out Fuel Pressure Regulator. All the problems went away. Runs Fantastic now!

 

[K1w1Boy]

Excellent outcome!

It would be interesting to know why FPRs go bad - they especially seem to hate sitting around doing nothing with gas going stale

 

[mcromo44]

Excellent outcome!

It would be interesting to know why FPRs go bad - they especially seem to hate sitting around doing nothing with gas going stale

I highly suspect it is primarily, or exclusively due to the ethanol content in gasoline.
And the higher the ethanol content, the faster the effect upon the particular elastomer material used for the diaphragm.
There's not much ethanol free gasoline here in North America, it's more how much there is in it.
And Methanol might be worse, but it's largely been displaced by ethanol, perhaps totally displaced, I'm not aware of any methanol use in gasoline in Canada, but don't at all know about the USA.

 

[K1w1Boy]

I highly suspect it is primarily, or exclusively due to the ethanol content in gasoline.
And the higher the ethanol content, the faster the effect upon the particular elastomer material used for the diaphragm.
There's not much ethanol free gasoline here in North America, it's more how much there is in it.
And Methanol might be worse, but it's largely been displaced by ethanol, perhaps totally displaced, I'm not aware of any methanol use in gasoline in Canada, but don't at all know about the USA.

Right - so the diaphragm gets affected by that component in the fuel, and that's that.

 

[robroten]

The ethanol mandate in our fuel is one of the biggest boondoggles of our time. Absolutely makes no sense in any way, shape or form.

 

[mcromo44]

The ethanol mandate in our fuel is one of the biggest boondoggles of our time. Absolutely makes no sense in any way, shape or form.

I agree. Ethanol does have the advantage of being an oxygenated fuel and does help with Octane Rating. BUT once one looks at the industrial ethanol production process from stem to stern and compares it to its thermal heat value, I echo your exact words "Absolutely makes no sense in any way, shape or form". Unless you are a mid west corn farmer!

 

[robroten]

Unless you are a mid west corn farmer!

My daughter: Daddy, if ethanol makes no sense, why do we burn it as fuel?
Me: Well... the first round of the presidential race is the caucuses in Iowa. So nobody is going to slay their golden calf.
Daughter: We can't be that stupid!
Me: Yep. And there's a whole lot more stupidity where that came from!