weird problem with hesitation/miss 72 Sat 440

[jprather]

ok, so... 72 satellite, 440 / 850 demon double pumper, MSD red box and distributor..

car runs great until.. I get on it hard, then it never recovers?

if I drive from cold start, runs perfect, can driver for hours.. runs prefect.. hammer on it, and it starts with a hesitation / miss under LIGHT acceleration, does fine if i go 1/4 throttle or more. will continue to do this until i leave it sit over night, then fine again.. WTH.. fuel press stays on 7 lbs, temp good, oil pressure good .. what am I missing ?

 

[pnora]

Possible crap in the carb getting pulled into a jet. Stays there while running and drops to the bowl bottom after sitting.

 

[66Satellite47]

Maybe float level, or inadequate fuel pump.

 

[Ironbuilt]

I would start with the carb. If it sat for a while, crappy gas could have gummed up the jets, float, etc. (?) Besides, that's the easiest place to start.

 

[Runner71]

As above. Swap fuel filter, cut it open and look inside(if its steel). Full service of the carb and check float lvl.

 

[pnora]

He supposedly has 7 psi. fuel pressure.

 

[72sunroof]

He supposedly has 7 psi. fuel pressure.

Is that at idle or wot?
Weak pump can have good idle pressure
But most likely a float level, needle and seat or trash in carb.

 

[jprather]

finally pulled carb last night... I hate this new gas !! looked like some small clear gummy bears where living in there ! I little bit of trash, and 1 clogged port, now to finish cleaning and put it back on

 

[Billccm]

finally pulled carb last night... I hate this new gas !! looked like some small clear gummy bears where living in there ! I little bit of trash, and 1 clogged port, now to finish cleaning and put it back on

Assume this fixed your problem? Just curious.

 

[jprather]

sorry,
yea, i guess it just turned out i got some bad gas ! after i got the gummy bears out of the carb, i went to a different gas station to get gas, cleared up

 

[YY1]

Are you running non-eth?

 

[jprather]

all i could get locally was 89 non eth., i had to go to 10% to get 93

 

[YY1]

Have you tried it on 89/90?

My 1969 440 with a mild cam does just fine.

I have to assume it's a 10.1:1 engine but I have no idea what the cam is other than is has just a bit of lope.

 

[jprather]

yea, i tried the 89 straight gas, lots of valve clatter / pinging

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