vapor locking on 73 with 71 carbs PERCOLATION!

[hls3073z]

1 hour ago, Burl said:

Also in Austin TX and experienced a similar problem up until last month.  I had been filling up the gas tank every time I got gas at a Shell station. .  Driving only 25-30 miles a week left a lot of gas in the tank.  It would take me 3 months to fill up again.   With the ethanol blend we have these days  I decided to run the tank down to only a couple of gallons.  Instead of filling up I only put 3-4 gallons in with some ethanol additive and changed to Phillips 66 so the gas didn't get old and break down.  Haven't had the problem since and ran the car yesterday in the heat.  I still have the mechanical fuel pump, with AC but added a radiator shroud.  So far so good ?

 

In all fairness its been 3+ years since I drove the car.  I'm going on experience to what it did even before ethanol came out.    As I mentioned before way back in the late 70's I switched to a flex fan and that helped plus I had no more water pump failures.  But on extra hot days like lately it  would stumble on take off from traffic lights.  As others mentioned Nissan wrote an extensive document about the  problem so its well known.

It could be that that when my 73 was converted to 71-72 round top carbs that something was left out that makes the percolation worse.  Coolant no longer flows thru that chamber, I think that would be beneficial in reducing it but who knows.  For the moment I've got the engine out and I'm going to repaint the engine bay so this percolation problem will have to wait.

Regarding the ethanol.  If you go to the Walmart Murphy gas at 1431/Parmer, also at 620/183  they are selling ethanol free gas now.  I have been buying it for my boat and all my lawn mowers etc.  What part of town do you live?   

[Burl]

I am close to Lake Austin Blvd and Enfield.  Heck both of those stations are a long way from me....

[Patcon]

38 minutes ago, Burl said:

I am close to Lake Austin Blvd and Enfield.  Heck both of those stations are a long way from me....

There are websites that can help you locate ethanol free gas. Do a search on Google

[SteveJ]

19 minutes ago, Patcon said:

There are websites that can help you locate ethanol free gas. Do a search on Google

http://www.pure-gas.org

[Burl]

Thanks.  Looks like those 2 are the only ones in the greater Austin area.  Heck they are 60 miles out there and back.  ?

 

 

[Patcon]

1 hour ago, Burl said:

Thanks.  Looks like those 2 are the only ones in the greater Austin area.  Heck they are 60 miles out there and back.  ?

 

 

Good excuse to drive the car though

[Burl]

You're right except LOTS and LOTS of traffic!  ?  When its get cooler I might go out there and fill up!  

[hls3073z]

not a big deal, I made that trip down and back for 25+ years, even before Parmer Ln was invented.  If that AC is working like it should the heat should not be a factor.?

If there are any Walmart Murphy stations being refurbed take a look.  The pump will have a blue plastic cover, kinda like they do AVgas which is also a good alternative if you are close to an airport.

[Burl]

Is the gas premium?

 

[hls3073z]

No, I think its like 88.  it does cost about 25c more.  My chainsaw, weedeater, and boat love it.  I wouldn't have thought that there would be enough demand but there it is.  It may be related to a recent EPA ruling giving some relief to refiners who didn't have a good  source of ethanol.  Problem is the corn states are lobbying hard to overturn.

Obviously AVGAS is primo stuff but may cost $4 or more.

My daughter went off to Japan for 2 years.  I dutifully drove her car up and down the block on a monthly basis.  What I did not realize was that the ethanol was absorbing water causing the tank to rust.  When she got back the fuel filter kept clogging until we replaced the fuel tank.  I wish I had access to no ethanol back then.