Carb Vent

reddog · Post by **reddog** » Sun May 29, 2011 9:52 am

I have been connecting all my vent lines for my wipers. Everything works great but when I connect the crossover to carb tube it sputters under power and will only run well if the choke is part way on. Anybody got any ideas?
Thanks Reddog

Post by **wesk** » Sun May 29, 2011 10:16 am

Make sure your tubing between the carb and crossover tube is clear. Make sure the tube inside the crossover tube is not plugged as well. In other words be sure you can blow thru the end of the tube that connects to the carb into the crossover with no back pressure evident.

reddog · Post by **reddog** » Mon May 30, 2011 5:52 pm

Shes clear it almost seems like it is pushing air through when it is running?

henrydes · Post by **henrydes** » Tue May 31, 2011 6:31 am

Had same problen...Found that some idiot had painted the crossover tube and got paint in the tube fitting (me)

Post by **wesk** » Tue May 31, 2011 9:56 am

That is possible. Look inside the crossover tube. Is the 90 degree tube that the vent line connects to facing the carb or the air cleaner? Can you run a wire thru that tube?

The fact that you must add choke to keep the jeep running with the line connected means the carb has begun to run lean and that can only happen if the vent line you connected to or the port and tube in the crossover is plugged or sucking on the line.

reddog · Post by **reddog** » Tue May 31, 2011 7:08 pm

There is only 1 90' tube inside the crossover tube and it is attached to the port that goes to the distributor vent it is facing to the air cleaner. The port to which I have the carb vented to is just a straight in threaded stud and the hole is unobstructed.

Post by **wesk** » Tue May 31, 2011 11:55 pm

Then we can offer no help. What you are experiencing can only be an act of God.

If the tubing and the port are unobstructed then the connection of the tube should have absolutely no effect on how your carb runs.

OKCM38CDN · Post by **OKCM38CDN** » Wed Jun 01, 2011 6:12 am

I would suggest running a pipe cleaner or small piece of semi flexible wire thru the vent on the crosscover tube... critters like to get in there and sometimes you cannot see them...

Hope this helps...

Cacti_Ken · Post by **Cacti_Ken** » Wed Jun 01, 2011 9:00 pm

If the tube is clear to the carburetor, I don't know if this would help but might be worth a try. Soilder a 90 deg. tube to the fitting that goes to the carb vent and face the opening toward the air cleaner so the air is forced or routed into the tube when the engine is sucking air. I made mine that way and never had a carburetor problem.
Wes is the expert but this might be worth a try.

Post by **wesk** » Wed Jun 01, 2011 10:20 pm

The M38A1 crossover tube did just that and used two 90 degree tubes both facing the air cleaner.

whydahdvr · Post by **whydahdvr** » Thu Jun 02, 2011 5:56 am

Ken,
Do you have a picture of what that looks like?
Thanks.
-Josh

Cacti_Ken · Post by **Cacti_Ken** » Thu Jun 02, 2011 9:03 am

The tube is 1/4"