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71 HS-4 SU What have I done?

  •  06-05-2007, 9:27 PM

    71 HS-4 SU What have I done?

    Around the first of this year I took ownership of a 71 B roadster from my neighbor, who had it for a year and a half in his garage gathering dust.  Took 5 hours to get it started and across the street to my place.  After a few hours of looking and fixing, it actually ran fairly well.  I took the wife to Yosemite the first of May (Yosemite in an open car - WOW!).  The B ran okay but had a mild flat spot on acceleration - probably just needs the SU's checked out I think.  (Forty years ago I was pretty good at tuning SU carbs as I spent three years building and maintaining a Bugeye Sprite for the owner/driver).  Read the Bentley manual a couple of times and went to work.  I pulled the float tops off and checked inside.  No needle valves but some sort ball valve mechanism (Grose-Jet?) that seemed to work okay but was not set at 1/8 inch float level per Bentley.  I put the floats back on the carbs, but managed to connect the fuel inlet to the bowl vent pipe the first time - had gas coming out the jets.  Okay, just put things back to where they were supposed to be and proceed on.  Now, what's the next step?  Oh yes, warm the car up before beginning the mixture adjustment.

    Well, it did not run well when I took it out for a short spin (hey what the heck, I knew the carbs were off a bit - what did I expect?)  I got back to my garage and proceeded to do the steps according to Bentley.  When I finished, the idle was better and the two carbs were in synch according to my old UniSyn.   Lookin' good!  I offer to take the wife out for lunch as a trial spin.  We live in the foothills and everything is downhill.  The B acts like it is not getting enough fuel on the downhill and is lacking power.  We got downtown to the Post Office to mail some letters and that is as far as we got.  The engine would not run off idle.  Opened the hood and found no gas in the fuel filter.  The filter is plugged, I think.  Lucky me, the Post Office is at the other end of the block from an auto parts store that sells me a new Fram fuel finter just like the one on the car.  Unfortunately, it does not change anything and the engine still does not run off idle and the filter bowl remains empty.  We go home on a string.

     Aha!  It must be the fuel pump.  I will order one from Moss and fix the problem and we will be back on the road in no time.  Well, not quite.  While poking around the front end I happen to observe that the left front tire has no tread on the inside edge, so along with the fuel pump, I order new bushings for the front suspension.  Then new A-arms.  Then rebuilt spindles.  You know the drill.  Oh yes, I did put the new solid state fuel pump on too.
     

    Unfortunately, the fuel filter remains empty.  I have taken the line off at the front carburetor and pumped into a container with good fuel flow.  I have also taken the vent line to the charcoal canister off with no improvement.  What could I have done to the float assemblies to cause this problem?   Is the Grose-Jet float adjustment different than the needle and seat unit?  What should it be?

     


    Oh, to be as young as I think I am.
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