Flathead running rich

C

camswax

Junior Member
Hi all hope someone may have some ideas on what could be going on with my engine. I have an 8ba 3 5/16"bore 4 1/8" stroke potvin moon cam Jahns solid skirt Pistons it's been ported polished running Malory twin point ignition champion 10hc plugs brand new stromberg 97's with 45 main jets 65 power valve. And edelbrock super duel intake. But it seems to rune rich could the jets be to big???? I can't seem to get much response out of the mixture screws the engine will run with screws out of one carb but not both. Is it hard to set mixture with a big cam???? And input would be great thank you Jason . Also I have been over the whole engine numerous time looking for vacuum leaks can't find any.
 
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Carb where you can remove the idle screws has a problem. While you are fixing things, reduce all the jets to 44s. Set idle screws to 1 and 1/4 turns out to start with.
I have an Edelbrock Super dual with 97s and use 44s.
Good luck
 
cams,
X100 what Bruce says. K & N makes the only element that won't choke
your motor IF you are using the little chrome air cleaners. On rare occasions the
power valves have been known to leak....I emphasize rare occasions.
Charlie ny
 
The 45-65 is the standard set up for ONE 97. Adding additional carbs. your going to have to cut down the fuel. I run .043 & 69 my cam is much milder than yours and the engine is 3.062 with a stock crank. 44 sound as a good starting place and maybe 68 With the dual set up engine vacuum will be lower and then adding a tall cam should make it a bit less also.
 
Thanks for replying im running The little Chrome scoops with The dome bug catchers. Do you mean the round louvred type?
 
Strombergs do their best when gathering air from a non-turbulent, unrestricted, dead-air space. Be sure your scoops are facing towards the rear.
This also helps prevent siphoning fuel at speeds over 150 mph!
 
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Thanks Uncle Max......my carbs seem to foul up at speeds just over 145MPH, I am going to reverse the scoops and report back to you!...Matt in Alameda
 
Thanks uncle max what do you think about the # 45 main jets im running in my engine? To big I think I will try some #42 thanks again for the tip on the air cleaners.
 
Take off whatever is on top of carbs for a test..easy and quick. All matter of shiny stuff up there needs evaluation.
Slightly smaller jets may well be indicated, but I doubt stockish jetting is far enough off to be an in your face problem...
Remember that retarded ignition/slow or inadequate advance can mimic some symptoms of richness, including loading the plugs
worry about bowl vent, especially front one...fan is probably right there...fan blast could slightly pressurize bowl, effectively increasing pressure drop in venturi...build a little windshield for that, like the ones used on some gas fired heater setups so it is shielded a bit.
 
It seems to be better the last few days a little bit of black smoke. My fuel pressure was at 3 I turned it back down to 2.5 thanks for all you r help. I have really enjoyed the comments thanks again.
 
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