Thread: Rochester jet size ?

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Originally Posted by shawnlee28

Checked the float level and it looked very very close.........plenty high to fill the accel pump well and everything else is in the bottom of the float area...both jets and the main valve are at the bottom....valve seems free and so is the spring loaded rod that sits on it......

Thanks

Shawn,
IMO, float level is right or wrong, but never "close". The flow through the jets is due to the head of fuel in the bowls, and a very small difference in level makes a big difference in flow. Get a carb kit, take the carb apart and clean it thoroughly, and then re-assemble it according to the instructions, paying close attention to getting the float level dead on.

Originally Posted by rspears

Shawn,
IMO, float level is right or wrong, but never "close". The flow through the jets is due to the head of fuel in the bowls, and a very small difference in level makes a big difference in flow. Get a carb kit, take the carb apart and clean it thoroughly, and then re-assemble it according to the instructions, paying close attention to getting the float level dead on.

Will check again......but I did get a rebuild kit and it came with gauge and it was within a 1/32second......maybe right under a 1/16th to the high side.....measuring in exactly the place shown to exactly the spot on the float and the float appeared to be almost exactly level after set, which is what the paperwork said it should be........when I say close, we are talking within a 1/32 .....about the thickness of the line on the gauge that was sent....very very close.

not more than a 1/16th.......

I am starting to think maybe some one has done something to this carb on the inside beyond what I can figure out, as it looked inside to have been taken apart quite a few times....just little nicks and dings in places that could only happen after it was taken apart, even has a helicoil in one of the threads from the base plate to the body.........to say this one has been apart a few times is a understatement.

I rebuilt and edelbrock 1405/quadrajet on my last build and it looked pristine inside, when done it ran perfect with a minimal of adjustement, engine fires up in a second after the rebuild...........this one looks like it has been apart and all the pieces were tossed in a spare bolt bucket and was shook back and forth 100 times........all the venturi legs look like they have dings in them and all the screw heads look like they have had the flat head on them 100 times taking it apart............someone could have drilled/plugged or swapped something inside I did not notice.


Not saying I do not make mistakes....I make plenty.......but I try to go right by the numbers on stuff I have not done a 100 times and take my time and pay attention looking for small details.......

I have only had one other carb act like this and it was literally a carb from the junk pile out back of someones shop....I was broke and young and had to have one to be able to drive to work......took it all apart with no kit/no gaskets or new parts and got it working minus the accel pump that was shot in it.....it acted like this one, but this one is worse than the carb that was getting no pump shot from a shot pump......


Granted it probably needs a valve job after 30 years with no leaded gas......but it feels like it has a decent amount of vac....runs fine and pulls hard once you are past the dead spot......fires right up and idles perfect, revs up as high as I feel taking it without a tach......as these motors top out at approx 4500 rpm, I am sure I have been revving it close to that.........it is just the pesky dead spot right where I need the rpm to use the clutch.....

I have turned the timing both ways as far as I dare and it made no difference in the dead spot..........

The only thing that makes any difference is to set the choke valve at a 45 degree angle and it runs like it should then....runs perfect, starts perfect,revs perfectly........that tells me it needs more fuel and with the 52 jets in it which are big enuff for a small v-8, I am not sure where I can get the needed fuel from or where it is missing from more correctly.

It could be that when it is rich/choke at a 45 it covers up the real problem.........maybe the vac advance is not working correctly or the mechanical is off...not sure if a rich condition would cover that up.

With the choke blade at a 45 I can punch it full throttle as fast as I can and it comes to life instantly up to as high as I dare rev it.......perfectly and crisply...no hesitation or anything all the way up.

If I got in it for the first time and had no idea the choke valve was at a 45, I would say the engine runs great! ...especially for a original mid 60`s motor......I would say it runs incredible!...............untill I saw the choke at a 45 and then it would be why is it like that....that does not seem right.....

Well, thats my saga on this one....all I can do is keep going down the list and eliminate things one at a time.

PS....the valves are fairly good as it does not suck a rag back in the exaust pipe....had a straight 6 with a bad valve and it would almost snatch a red shop rag out of your hand....

I appreciate the reply.....but I am thinking it is something else, I will definatly set it again as it only takes 5 mins or less to pop the top off the carb and do it.