Hi all,
I was hoping to get some help with a really strange problem. I was
attempting to adjust my carbs today and had a heck of a time. I was using
the aid of a Oxygen Sensor and a digital meter to set my mixture. I thought
things were going pretty well, once the sensor got hot I was off and running
but I noticed that the richness varied greatly from a warmed up state and a
hot state . When the engine was warmed up ( I would consider it up to temp)
I the I set the mixture for @ 500mv which is just above stoich , I then
checked this by cupping my hand over the carb, no effect , and then lifting
the piston a bit I noticed it didn't like this much if I went too far. But I
noticed that as the engine got hotter the sensor reading shot up to @950mv
and the engine was idleing rough. When I lifted the piston the engine sped
up bit and when I covered the carb it stalled. I restarted and began to lean
out the mixture but no matter how far I backed off I couldn't get the
mixture too lean out. In fact I think I backed the adjustment out 4 or 5
turns counter clockwise to no effect, I was afraid I loosen the thing too
far or I'd loose it. I thought perhaps the float was off so I took the carb
off and it was off @ 2mm from spec , the needle seems fine, they also have
Gross Jets installed . I should add that the carbs were rebuilt by Gary
Martin about two years ago. I was wondering if the temperature compensators
could be to blame , how do you check them and are they fixable or
adjustable? Also I noticed that no matter how I set the carbs at idle they
all leaned way out at higher rpm. I could do nothing to fix this. I'm
running triple Strombergs 10:1 compression , hot cam and ported head with
oversized intake valves. It seems here the needle profile is the problem , I
know that needle selections for Strombergs are slim, any advice out there?
Thanks Guys!
Nick Gemas
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