[TR] Spring Time in the Smith Garage

[TERRY SMITH]

Hmmm.  As ever, thank you, Randall.  Yep, forgot about the choke spring.  Was intending to describe the jet housing one.  Never knew there was a distinction that separates vapor lock from percolation (a new term to me).  Felt I would be "cheating" with a fan only because I had a new problem but would be addressing it but not fixing it directly.


I'll redirect the fuel line.  Tell me, how does one add extra insulation to the heat shield? 


With the jet housing springs loose, would I be correct in assuming there would be some erratic variations in mixture and might these for some reason be more pronounced at idle?


Thanks again,

Terry

> On July 5, 2019 at 9:59 PM Randall <tr3driver at ca.rr.com> wrote:
> 
>     Which springs are you talking about? There's a compression spring on the jet housing that just keeps the mixture but from moving. And an extension spring to the side that returns the jets to the non-choke position after using the choke.
> 
>     People use the term "vapor lock" to cover a lot of different actual problems. True vapor lock (IMO) is when the fuel boils before reaching the fuel pump (or inside the pump). The pump is not effective at moving vapor (hence quits pumping and becomes vapor locked).
>     I've never seen that on a TR. And rerouting the line after the pump wouldn't help if that was the problem.
> 
>     Your problem sounds more like percolation, where fuel boils in the jets and pushes liquid fuel out into the carb throats. (Like an old fashioned coffee percolator.) If so, anything that helps keep the jets cooler will help.
> 
>     I might try rerouting the fuel line to the stock location, under the thermostat housing (where its cooler); and adding more insulation to the heat shield.
> 
>     Not sure why the fan is "cheating"; the problem is caused because we can't buy " summer" gas any more. Any method to adapt to available fuel seems valid to me. (My intention, if I ever get back to that point, is to make the electric fan keep running for 5 or 10 minutes after shutdown.)
> 
>     A vacuum leak would make it start easier with the choke. Have you tried that?
>     -- Randall
> 
>     On 5 July 2019 16:43:31 GMT-05:00, TERRY SMITH <terryrs at comcast.net> wrote:
> 
>         > > 
> >         Spark issue is solved (bad electronic ignition).  Resulting overheating problem is solved (timing/mixture issue).  Yet driving an hour in today's heat, the temp needle stayed normal, but the car was a trifle slow to start when I got back to it.  Put the pedal all the way down and it fired up, but engine fluttered at low RPM's until I'd reved it for a short time.  Sounds like classic vapor lock.  Afterwards, the car runs smooth and with great power and acceleration, except idle moves a bit up and down and engine stumbles sometimes at low RPM.  When I got home I pulled the plugs and found no black, so apparently I'm not running too rich.  Two questions:
> > 
> > 
> >         One:  the obvious.  Pulling the air cleaners off, I found I'd forgotten to put the springs back on that hold the jet assembly to the carb.  Duh.  So what are the symptoms of that, other than low scores on IQ tests?
> > 
> > 
> >         Two:  the probably obvious.  I'd rerouted the fuel lines under the hood.  They now go over the thermostat area.  I've encased the tubing in slitted fuel line to give them some insulation, but it hasn't solved what seems to be vapor lock.  I do have the aftermarket insulative plate under the carbs to bank heat off the manifold.  I have a fan I could install that might bring the temp down after engine shutdown but that seems a cheating type fix.
> > 
> > 
> >         Three:  the awful.  It could be a vacuum leak, I suppose.  Please, nobody suggest it is because then it might be true....ugh.
> > 
> > 
> >         Terry Smith, '59 TR3A
> > 
> >         New Hampshire
> > 
> >     > 


 
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