I've been struggling with fuel starvation-vaporization of fuel in a '76
TR6. What I've done so far, boiled the tank, new fuel lines, new filters,
new pumps, rebuilt the carbs. Today I rechecked the carbs since the
problem appears to be caused inside. Took both apart and they were perfect
inside. Cleanest carbs I've seen. FTHOI I changed one grose jet for a new
one, reset floats, blew compressed air through all passageways and used
carb cleaner everywhere I could. Checked Temp Comps, Chokes and
bypasses-A-OK.
I noticed that the float bowl vent has two interconnected operating
systems. There is a spring loaded lever that closes the vent to the carbon
canister when you hit the gas and switches to somewhere else. There appears
to be another internal passageway that then takes over the venting. My
rear carb appears to be blocked in this passageway. My theory, bizarre as
it may seem, is that the bowl vent isn't operating at driving speeds,
therefore the float bowl is pressurized with vapor, not allowing fuel in,
thus starvation. The car runs rough when the initial charge of fuel in the
lines, bowls and filter runs out, being replaced by pre-vaporized fuel.
This is evidenced by the empty glass fuel filter.
Does anyone have any idea what I'm talking about? Anyone ever experienced
it. I'm about ready to give up and use a set of early 6 carbs just to get
it running right.
Bob Kramer, Austin TX
Hill Country Triumph Club
TR6x3, TR250 x3, TR3A vintage race
rgk@flash.net
|