78 cutlass W-31 build

Clutch

Geezer
Apr 7, 2017
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Is the fuel filter clean or new? I had problems similar to that when I had a clogged fuel filter. It didn't want to shift from 2-3 it would just sort of hit a wall and wouldn't accelerate..just an idea
The hole carb is basically new just back from a carberetor builder with a new filter
 
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Oct 14, 2008
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Good point on the APT position. I have mine turned in 2 turns in right now, it gained me 3 mpg but gave me a top end miss. You would want to start with one turn out. In your case, talk to the guy who built your carb. Also make sure your mechanical and vacuum advance are working properly before condemning the carb.
 

DRIVEN

Geezer
Apr 25, 2009
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Sounds like your carb guy knows what he's doing so I'd be hesitant to screw with that especially since it's been an ongoing problem.

Just curious, how old is the gas in the tank? Gas with ethanol has a pretty short shelf life.
 
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Clutch

Geezer
Apr 7, 2017
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Sounds like your carb guy knows what he's doing so I'd be hesitant to screw with that especially since it's been an ongoing problem.

Just curious, how old is the gas in the tank? Gas with ethanol has a pretty short shelf life.
It's new 93 octane pump gas
 

Clutch

Geezer
Apr 7, 2017
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Here's one for you. How do I test a vacuum modulater on a th350? It's brand new but idk were that guy gets his parts from. If it's bad it could be my lean problem and my shift problem... Or no? Idk?
 

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
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Some of the aftermarket ones have a flat blade screwdriver adjustment inside the vacuum hole.
 
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Clutch

Geezer
Apr 7, 2017
5,183
10,900
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Brick NJ
Here's one for you. How do I test a vacuum modulater on a th350? It's brand new but idk were that guy gets his parts from. If it's bad it could be my lean problem and my shift problem... Or no? Idk?
Some of the aftermarket ones have a flat blade screwdriver adjustment inside the vacuum hole.
Yes it does and I've been all the way both ways. What I was thinking is if it's bad it could be a vacuum leak and well you see were I'm going
 

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
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I think if the diaphragm was ripped trans fluid would leak past it.
 
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TURNA

Rocket Powered Basset Hound
Jul 24, 2009
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I am not sure but you could pop it out and suck on it with your finger over the other end see if it holds.
 

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