dual carbs what jets you using here in cali

34flathead

34flathead

Senior Member
Hey everone, I am now starting to try and get better gas mileage, Im running 2 97s on a Fenton intake, warmed 49-53 flatie, 4"merc crank.

havent pulled a carb to see what is in them now, but what are you running with dual carbs here in sunny california.
rich
 
34flathead said:
Hey everone, I am now starting to try and get better gas mileage, Im running 2 97s on a Fenton intake, warmed 49-53 flatie, 4"merc crank.

havent pulled a carb to see what is in them now, but what are you running with dual carbs here in sunny california.
rich
Click to expand...

Rich.
I'am using .046 jets and 65 power valeves, and get 14 miles to the gallon. I have tried .042 to .048 jets, and got the best power, and good all around driveabilty with the 46's. This is with an .040 bore, four inch stroke, and Weber F4 cam, in an 1800 lb Roadster.....Ed
 
thanks guys, i will pull one off this weekend and see whats inside, as i am only getting 11 miles to the gallon, and have been told 14 and 15 miles was bad, but have not been told what jets and main or power valve is being used to accomplish this, i have also read on the HAMB of flatheads hitting 18 miles to the gallon.
rich
 
I'm at 4000 ft with two LZ's and get 22 mpg with .042's & # 69 pv's. Oh yeah, the overdrive helps...
 
i have 2 more 97s in the reading room, with #42 jets, i just looked, but did not take the top off to see the power valve.

i smell a little gas but not a lot that would say hay i smell gas.

the tops weep a little compared to how wet they were before i put a fuel regulator on.

im loving that 22 miles i keep hearing about.

rich
 
Last edited:
'34,
Do not overlook the possibility that your existing power valves
may be leaking. Many new out of the box PV's and certainly many used
PV's leak. Max and I have simple but effective devices to check for this
situation.
Charlie ny
 
'34,
Stromberg power valves new and used have a tendency to leak.
Max and I have simple but effective devices to check for leaky PV's.
Charlie ny
 
ok, so i took the carbs off and opened them up, jets are #45 and the power jet is # 65, the other set of carbs have #43 jets and #69 power jet.
i will use the second pair's base gasket on the bases that i am leaving on because i dont want to mess with the linkage that connects the bases together.

question, do you just put the top back on the carb or do you put oil on the accelorator pump leather?
rich
 
Last edited:
'34,
OK the jets are stamped with some number and so are the power valves....did you determine that the jets have not been opened up....very
common......and that the power valves don't leak.
Not much sense in going further until you know the jets and power
valves are good. Don't forget to pull the emusion tubes to be sure
they aren't plugged.
Charlie ny
 
charlie ny, i have the carbs off now, how do i test to determine if the power valve is leaking or not?
i have seen on here and will check the search thread to get the size of drill bit to verify the # on the jet, these were built back in 04 for me, and the set i put on i purchased when the guy decided to chevy his '40 coupe were built by the same guy.
the second set are on and the flatie now, smokes at idle, i do not know how to adjust the air fuel mix screws.
rich
 
Last edited:
There is no drill # that you could use. You need a pin gauge set which has presision short rods in .001 incretments to measure them. ken ct.
 
i just finished searching the search thread and my best friend google, it will need to be a pin set to verify the size.
now i am going to see what i can find online for these.
also the #45 jet that came out of the carbs i took off, the hole at the top and bottom dont matter, just the hole in the middle right?
rich
 
If you can wait till after Bonneville, send me your carbs and I'll go through them.
I'm in a good mood - no charge.
 
i tried to email Chris some pic's but they were too many and it locked up my outlook email, my pm should be working, unless that has stopped too.
that would be just great uncle max.
rich
 
34fivewindow said:
Rich.
I'am using .046 jets and 65 power valeves, and get 14 miles to the gallon. I have tried .042 to .048 jets, and got the best power, and good all around driveabilty with the 46's. This is with an .040 bore, four inch stroke, and Weber F4 cam, in an 1800 lb Roadster.....Ed
Click to expand...

The F4 is a big cam isn`t it?
I think Vern Tardel has one in his `32 roadster if i remember correct...
I bet it sounds great!!!
 
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