Carter WO Plunger and Rod Assy

[bwtufts]

I rebuilt my WO a couple months ago with a full rebuild kit from Walcks. It ran great for a while, but after a long day in the mud/water she started to stumble and sometimes die if the accelerator was pushed quickly. Pulled the top of the carb off and noticed that the Accelerator Plunger Assy was not moving down when I pushed on the gas pedal. It was actually so stiff I had to put a lot of pressure on it to make it move manually. It seemed like the gasket/ leather cup at the bottom of it had swelled up so much that it was scraping on the inside walls of the carb. Put the old one in and it works just fine and moves freely as it should and accelerator circuit works as it should again.
 
Has anyone had this problem before and what would cause the little gasket/ leather cup on the plunger to swell so much that it was in a bind?
 
Are there any issues with running the old one as long as it works?

[rocketeer]

You answered your own question, water swells leather.

Larry

[bwtufts]

That was what I figured, but I'm still at a loss on how the water got up inside the carb to make it swell. I was only in water once, that was no more than 3/4 the way up on the tires.

[calvinhunt]

I must add here that when I overhauled my carb I started with a basic overhaul kit.  I was disappointed with what it had in it so patiently awaited the arrival of a master overhaul kit.  After assembly I was disappointed with the performance.  I ended up disassembling it again and reinstalled some original parts that I felt were better than some of the ones that came in either of the overhaul kits.  It's been running great ever since.  

[bwtufts]

Thanks for the input Calvin, I saw that Walcks had the NOS kits and wondered about their performance. Of course I should have known that original always works better than most of the REPOP stuff now-a-days. May go ahead and pick one up for the future when the carb acts up again!

[Gunslinger]

Back to Larry's comment if we could, if you use a ethanol blend fuel will you have a better chance to swell the leather cup on the pump?  Ethanol attracts water, would that, could that have been the cause of the problem?  Speculating here that the old part had a chance to dry out, that might be why it worked when installed.  

Just thinking out load so to say...

[bwtufts]

That seems like a valid point in my eyes gunslinger, I had never thought of that. I had only ran roughly four tanks of fuel through it since the rebuild. I would hope that the water content was not that high in the fuel to have so quick messed it up. Then again, you never know with most gas stations now-a-days!!

On another note, I know in diesel systems leaving a fuel tank half empty will cause condensation to form in the fuel tank as it heats up and cools throughout the day. I would imagine this would be the same of a gasoline system as well.

I would be interested to see if anyone had looked into this possible problem before.