Mystery fuel consumption on v345 scout 2

[Bob Prohaska]

Some thing like one plug having the odd look points to that cylinder as the culprit but with out installing a new plug and retesting it would be very difficult to say for sure.

I agree the problem is local to that cylinder. For the moment I've cleaned the plug and am satisfied it's firing. The machine hasn't
been driven enough to learn if the fouling continues.

Verify no water in the fuel by either pumping some into a clear container, water will be clearly visible at the bottom. Or by draining some from the tank if the tank has a drain plug. Water should push past the threads once loose.

The only mechanical defect appears to be the size 2-008 o-ring sealing the needle & seat assembly into
the float bowl.Replacing it seems to have cleared up the high fuel level problems.

Far as I can tell all remaining problems were self-inflicted. One of the first things I tampered with was the idle
mixture screws. That the screw seals were leaking provided further confusion, but the real blunder was to
adjust the screws as if they were independent. They are not, there's enough crosstalk in the manifold to
let the engine idle almost driveably with one screw rich and the other closed off. Only now do I understand
the logic of setting both rich (1.5 turns out) and then only leaning them progressively to find lean best idle.
That's quite alien for somebody who's accustomed to dual carb setups. Learned my lesson the hard way.
The fuel coming out of the left venturi booster at high speed idle has gone away. Just how that works in
physical terms I don't understand, but the standard advice seems to be "check the idle screws" and it worked.

It's premature to say all's well, but the fuel consumption problem was most likely due to fuel level control loss.

Thanks to everyone who read and replied!

bob prohaska

 

[Bob Prohaska]

It's premature to say all's well, but the fuel consumption problem was most likely due to fuel level control loss.

Thanks to everyone who read and replied!

Finally got in some test driving. Two trips totaling 88 miles yielded 13.1 mpg, which is pretty
good, at least by historical standards. It'll take a while to accumulate enough mileage to make
checking the plugs informative.

One small revelation was setting the idle mix with the auto trans in gear. The drag of the
torque converter makes finding lean best idle much easier.

bob prohaska