Rich running 262 head scratcher

Bitburger

I have a 49 with a 262 2 bbl carb.  Cyls 2, 4 and 6 appear to be running normal. 1, 3 and 5 however are running very rich and are carbon fouled. Car runs decent but idles just a bit rough when low. 
Plugs are Champion J8C gapped at 32. WD-O Carb recently rebuilt. mixture screws are 1 and 1/8 out.

 Anyone have any thoughts?

Courtesy Man

A cyl compression test should be done - a vacuum gage could also be helpful. Good luck.

lostmind

Vacuum leak in manifold? Spray around intake , and underneath. 
Be careful around the hot exhaust.

Bitburger

Courtesy Man said:

A cyl compression test should be done - a vacuum gage could also be helpful. Good luck.

Compression test showed all cylinders between 88 and 95. Vacuum gauge in hand.
Thanks

Bitburger

lostmind said:

Vacuum leak in manifold? Spray around intake , and underneath. 
Be careful around the hot exhaust.

Ok. I'll give that a try. What flavor spray ?   Thanks

superwasp

I've had good success with an UN-LIT propane torch. The propane gas will definitely change the idle if sucked into a leaky manifold. Works great on FI cars with hard to access intake runners.

Doctorvaux

Seems strange that only the odd cylinders are impacted. There may be a clue in the firing order 153624 and the affected cylinders. I wonder if one side of the distributor is not firing as strongly ?  I would suggest checking that the distributor cap is sitting properly and also checking for a bent dustributor shaft. Or possibly looking fir a crack in the distributor cap near leads 1,5,3.  Hope this helps.

Geoff

It's obvious that one throat is delivering more fuel than the other.  Nothing to do with ignition.  You can't just set the idle mixture screws at a determined position, you  have to individually  tune them.   Check the metering pin actuation and the  jets in the bottom of the bowl. 

Bitburger

Geoff said:

It's obvious that one throat is delivering more fuel than the other.  Nothing to do with ignition.  You can't just set the idle mixture screws at a determined position, you  have to individually  tune them.   Check the metering pin actuation and the  jets in the bottom of the bowl. 

So does one throat serve the even cyls and the other the odd ones. If so which side serves which

Bitburger

superwasp said:

I've had good success with an UN-LIT propane torch. The propane gas will definitely change the idle if sucked into a leaky manifold. Works great on FI cars with hard to access intake runners.

Tried the torch method twice with no change in idle.

There is one vacuum line from the intake manifold to the passenger side of the wiper motor. On the driver's side of the wiper motor there was no vacuum line either plugged or attached to wherever it goes to. So I ran a short line and stuck a golf tee into it. No change in idle.

BTW what does that driver's side vacuum line connect to ?

54coupe

There should only be one vacuum hose to the wiper motor.

Bitburger

54coupe said:

There should only be one vacuum hose to the wiper motor.

Mine has dual fittings one in from the intake and one out to ?

cheyenne7271

I’ve never seen a second port, maybe put a rubber plug on the second one if you’re getting a vacuum leak, not sure

Bitburger

cheyenne7271 said:

I’ve never seen a second port, maybe put a rubber plug on the second one if you’re getting a vacuum leak, not sure

I did plug it with a short line and a golf tee. No change in idle. A friend sent a picture of his 49 which also shows this second port. The line attached to it appears to run through the firewall but not sure to where.

54coupe

I wonder if this second hose goes to the wiper switch for the windshield washer? I've never had a Hudson with that feature, so I'm guessing now.

cheyenne7271

oh oh that makes sense, I guess the washer uses vacuum to move the fluid 

Bitburger

So with no vacuum issues found looks like I'm back to carburation making 1,3 and 5 run rich and 2,4 and 6 run normal. Back to Geoff's concept of one barrel adjusted richer than the other but does one barrel control the gas flow to 1,3 an5 and the other to 2,4 and 6 ?

Geoff

One side  feeds 1,2,3 and the other 4,5,6

Bitburger

Geoff said:

One side  feeds 1,2,3 and the other 4,5,6

Do you know which side feeds which ?

Geoff

Outside  for front and inside for rear. 

Bitburger

Geoff said:

Outside  for front and inside for rear. 

Thanks Geoff, that helps a lot.  I think I'm getting it dialed in so thanks to all who have responded.