Rochester 4bbl Carb Issue

[01 cummins]

I have a 88 Four Winns with a 5.7 350 and the carb was exchanged with a reman in 05. It smells and sounds like its getting a bit too much fuel. I changed the plugs the other day and the porcelain was dark brown.

The real issue is when I go to shift it in forward and if I shift it from forward to reverse when docking it falls on its face and sounds like its going to stall and then it will pick up.

I was told there are 2 air/fuel mixture screws on the front of the carb. The question is do I turn them clockwise or counter to lean it out, and which one do I start with the left or the right one? I read to turn the idle up a little and it should be done when its in gear.

The engine always starts right away, idles fine and the top end is fine.

 

[ENSIGN]

Re: Rochester 4bbl Carb Issue

sounds more like a shift interrupt switch or shift cable issue.

 

[dr_bowtie]

Re: Rochester 4bbl Carb Issue

clockwise to lean and counterclockwise to richer....

on those I would set them with a vacuum gauge as it doent take more than a 1/4 turn to make a good difference...

 

[01 cummins]

Re: Rochester 4bbl Carb Issue

It seems to do it more when it idles for a bit then I put it in gear. If I start it up and put it in gear within about a minute then it doesn't do it.

The throtle response is good too if its in nuetrul and I rev it up.

 

[dr_bowtie]

Re: Rochester 4bbl Carb Issue

yep sounds like it is loading up a little at idle...when it does it is the throttle still crisp or is it a little lazier than norma...

crisp is lean...lazier is rich...

 

[hoverman]

Re: Rochester 4bbl Carb Issue

i had a similar problem with my rochester on my 5.7 ended up rebuilding the carb and resetting the idle mixture screws to fully closed and then backed them off 2.5 turns each....engine idles at a steady 650 rpms now i did use a vacum gauge off the choke port to take readings.

 

[erikgreen]

Re: Rochester 4bbl Carb Issue

I have a 88 Four Winns with a 5.7 350 and the carb was exchanged with a reman in 05. It smells and sounds like its getting a bit too much fuel. I changed the plugs the other day and the porcelain was dark brown.

The real issue is when I go to shift it in forward and if I shift it from forward to reverse when docking it falls on its face and sounds like its going to stall and then it will pick up.

I agree with the earlier comment.. this is a dead giveaway for a lower shift cable problem. What's probably happening is that the lower shift cable is sticking, so your interrupter switch is being triggered to try to let the drive out of gear.

It's almost certainly not carb related if it just happens when shifting.

The engine always starts right away, idles fine and the top end is fine.

Yep, the carb is fine. Check your lower shift cable and interrupt switch.

Erik