I've had this problem for some time. Engine runs fine but is difficult to
start after sitting for five minutes. When it fires, I see a puff of black
smoke and I get a whiff of gas. After removing the air valves from the top of
the carbs, I see that there is about 1/4 teaspoon of gas in front of the
butterfly of the rear carb, and looks like its coming from the main jet. When
I pulled the carbs the floats dont leak but they were set a little high at
0.7" (spec is 0.63" to 0.67"). I rebuilt the carbs last year with new float
valves (not Grose jets), and I also use a small prefilter just ahead of the
carbs so the bowls look clean. The vent valve on the carb is working ok.
Does anyone have any thoughts? Percolation in the carbs? Float valve not
closing all the way?
Also, both carbs leak a little around the float bowl. I checked the float
bowl covers and they aren't perfectly flat. I hoped a new gasket would take
care of the problem, but apparently not. The cover has a raised line around
the perimeter that looks like its supposed to help in sealing. Should I risk
sanding the cover on a flat surface, or perhaps just put a thin coating of
sealer such as Hylomar on the gasket?
John Lumia
76 TR6
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