I'd say you are getting bits of grit or gas tank sediment caught under the
float needle, or in the case of the grose units, the ball, causing the fuel
to continue flowing even though the float is trying to close off the flow.
Install a fresh in line fuel filter just before the carbs. This should catch
the crap and solve the problem.
> Getting closer to the problem now.
> Took float bowls apart to check measurements on float level. Noticed
> front carb had more gas in it than the back one. Made a mental note.
> Put things back together and took for ride to see if I was still losing
> power and stumbling at 3500.
> Couldn't find a suitable stretch of road to sustain that speed so pulled
> off road and held throttle to 3500.
> Didn't take long. Sure enough problem still there. Car stumbled and lost
> power. Shut down and released hood to check on which carb was the
> culprit. Only saw pool of gas under car between both overflow pipes!
> Started car and from engine compartment held throttle, revving engine.
> Again, short time later, gas pouring out of front overflow pipe, car
> losses power, then comes to life again.
> So, what do I look for? BTW, these have grose jets in float bowls, so
> don't tell me they are not floodable!
> Dave Houser