Carburetor question

[Scout1067]

I have a AMC 258 i6 / 4.2l with a Weber 32/36 DEGV that the PO put on it with a K&N square breather. The last time I had a vehicle with a carbureted engine was in High School many moons ago (a POS 85 Cougar) so I am scraping memory and have been quizzing the hell out of my Dad to try and figure this out.

Two things really.
1. When I start the engine I always have to pump the hell out of it and rev it a few times before it settles in it idles at 850-900 rpm cold. The engine also runs rough cold but as soon as it hits operating temperature it smooths out and idles around 1000 rpm. I have looked and it seems to be choking ok. I adjusted the mixture and idle according to the instructions I found on the Redline website since I got a title from the PO and nothing else.

I can't find a manual for the carb at all and I am not really convinced it is a carb issue.

2. The second thing I find more concerning. When I open up the breather there is foamy, creamy looking oil in it. It gets so much oil that it is starting to soak through the air filter and I cant for the life of me figure out where that oil would be coming from.

Any help pointing me in the right troubleshooting direction is greatly appreciated. I am beginning to think the two issues are related but don't know how.

 

[JeffP]

I have a AMC 258 i6 / 4.2l with a Weber 32/36 DEGV that the PO put on it with a K&N square breather. The last time I had a vehicle with a carbureted engine was in High School many moons ago (a POS 85 Cougar) so I am scraping memory and have been quizzing the hell out of my Dad to try and figure this out.

Two things really.
1. When I start the engine I always have to pump the hell out of it and rev it a few times before it settles in it idles at 850-900 rpm cold. The engine also runs rough cold but as soon as it hits operating temperature it smooths out and idles around 1000 rpm. I have looked and it seems to be choking ok. I adjusted the mixture and idle according to the instructions I found on the Redline website since I got a title from the PO and nothing else.

I can't find a manual for the carb at all and I am not really convinced it is a carb issue.

2. The second thing I find more concerning. When I open up the breather there is foamy, creamy looking oil in it. It gets so much oil that it is starting to soak through the air filter and I cant for the life of me figure out where that oil would be coming from.

Any help pointing me in the right troubleshooting direction is greatly appreciated. I am beginning to think the two issues are related but don't know how.

Idle should settle down to 650 at operating temperature, not 1000. Set the air fuel ratio at lowest idle possible then adjust mixture screw(s) to attain the highest reading on a vacuum gauge. Assuming your ignition timing is correct and no vacuum leaks.
The shaving cream mixed with what may have come from a diaper is a major concern. I’m guessing it’s a foamy tan color. Could be one of two things... both bad. Very bad!
1. There is water mixed in with the oil. Likely from the cooling system. Head gaskets don’t go bad like they did 50-75 years ago and it’s extremely rare for one to leak on it’s own. More likely a crack.
2. Way too much oil. The counterweights on the crankshaft could be dipping into the oil, as the crank spins, it whips the oil similar to whipped cream. With the pan dry and a new filter it should hold 5 qts.

 

[Scout1067]

Idle should settle down to 650 at operating temperature, not 1000. Set the air fuel ratio at lowest idle possible then adjust mixture screw(s) to attain the highest reading on a vacuum gauge. Assuming your ignition timing is correct and no vacuum leaks.
The shaving cream mixed with what may have come from a diaper is a major concern. I’m guessing it’s a foamy tan color. Could be one of two things... both bad. Very bad!
1. There is water mixed in with the oil. Likely from the cooling system. Head gaskets don’t go bad like they did 50-75 years ago and it’s extremely rare for one to leak on it’s own. More likely a crack.
2. Way too much oil. The counterweights on the crankshaft could be dipping into the oil, as the crank spins, it whips the oil similar to whipped cream. With the pan dry and a new filter it should hold 5 qts.

Well, I hadn't considered a Head issue. I checked and there is no oil in the coolant and wouldn't a crack that allows them to mix in the head also lead to the coolant itself getting contaminated? That is what happened on my old truck when the Head cracked. I also don't see any evidence of oil leakage on the outside of the Head although the foamy oil is also on the inside of the front valve cover plug.

I just did an oil change two weeks ago and made sure I put 5 quarts in it. I sure hope it isn't the head as I will have a hell of a time finding a junkyard here in Germany with an old Jeep in it.

 

[Lumpy Grits]

Also-Very important the the 2 idle mix screws, are turned out the EXACT same amount, for a smooth/balanced carb function.
That looks like condensation foam in the cap-Take it for a 50-75 mile drive, see what it looks like then.
Short trip(less than 10 miles)is hard on engines.
LG

NOTE: WROTE THIS KNOWNING THE OP SAID WEBER-
My pee brain was stuck on Carter and such..........

 

[Scout1067]

Also-Very important the the 2 idle mix screws, are turned out the EXACT same amount, for a smooth/balanced carb function.
LG

I only see one mixture screw on the carb and the idle speed screw

 

[Lumpy Grits]

I only see one mixture screw on the carb and the idle speed screw

That is because there is only one. My mistake
Haven't worked on one of those Weber's in over 10 years.
See if this might help-
Weber CARBURETOR SET UP AND LEAN BEST IDLE ADJUSTMENT

LG

 

[JeffP]

Well, I hadn't considered a Head issue. I checked and there is no oil in the coolant and wouldn't a crack that allows them to mix in the head also lead to the coolant itself getting contaminated? That is what happened on my old truck when the Head cracked. I also don't see any evidence of oil leakage on the outside of the Head although the foamy oil is also on the inside of the front valve cover plug.

I just did an oil change two weeks ago and made sure I put 5 quarts in it. I sure hope it isn't the head as I will have a hell of a time finding a junkyard here in Germany with an old Jeep in it.

There are areas in the block that never see oil pressure, such as the crankcase. If it did, it is vented to the outside world relieving any possible pressure. So... depending where a crack might be, there is no pressure for oil to be forced into the cooling system.
The cooling system is however pressurized. 15lbs of hydraulic pressure is substantial! It wouldn’t take much of a crack to force coolant into the crankcase. For oil to enter the coolant, it would need to overcome the ambient pressure in the system.
No oil in the coolant is actually expected.
I’m not one who supports “engine rebuild in a can” but there is a product out there that performs miracles. I’ve seen it myself!
It’s marketed under “Blue Devil” brand. It’s common sodium silicate in liquid form, “liquid glass” and doesn’t hurt your cooling system or engine, but it plugs huge leaks! Check Youtube. From when I used it (twice) it worked as well or better! With your tiny leak, I’m certain it would work. Buy you some time anyway.
On both engines I tried it with, the blocks were cracked. Water poured out as fast as it went in! Even though I was extremely skeptical, there was nothing to lose by trying. It took about three minutes to completely stop the massive leaks! I watched the flow gradually decrease until it stopped. Ran the engines under normal conditions for another half hour or so, pressure tested the cooling system and it held! Several months later, still going!
Under the brand name “Blue Devil” it is quite expensive, but they do offer a money back guarantee. All it really is is sodium silicate. Buy that, it’s much cheaper!
Oh it also makes an incredible protective coating on paint! Like permanent wax!

 

[R717]

1. Sounds like you need to start from a baseline for getting the carb setup. How many turns out is the idle screw? Gently! Screw it in until it seats counting the turns, Webers should be between 1-2 turns. First thing, check all sources for vacuum leaks. Your symptoms are classic vac leak. Don't forget the power brake booster, I've seen a ruptured diaphragm give a large vac leak that was hard to chase down. Ill place a second post with two links that are great for setting up webers. This durn website seems to lose my posts when I embed links

 

[R717]

2. The emulsified oil under the cap - do you see any on your dipstick? I've seen that when close to oil change and the grommet for my pcv was dry-rotted and no longer sealing. Change your oil, let some seep out before removing the dipstick and look for any milky or chocolate oil. If none you don't have to worry about cracks or gaskets leaking. Be sure your pcv valve plumbed to manifold vacuum on the port. You shouldn't be getting oil blowing into the air cleaner except possibly at full throttle on a worn engine.


Edit - I just looked at your pictures, looks like your pcv is going to the air cleaner. That line should be going to manifold vacuum below the carb. You also need a way to get filtered air into the engine. A filtered breather at the back of the valve cover or a port from the air cleaner would work. This would also contribute to the condensation/milky oil on the filler cap, especially short trips as LG mentioned.

 

[R717]

Weber dgev tuning links

The documentation from Redline is pretty lacking, but there is a lot of good info on these sites

Weber Tuning Methodology

Tuning Webers

If you want to optimize your tune, you should pickup a jet kit from Redline or Pegasus racing. I remember i had to go larger on the secondary jet and i think smaller ony primary air corrector.

 

[JeffP]

Also-Very important the the 2 idle mix screws, are turned out the EXACT same amount, for a smooth/balanced carb function.
That looks like condensation foam in the cap-Take it for a 50-75 mile drive, see what it looks like then.
Short trip(less than 10 miles)is hard on engines.
LG

NOTE: WROTE THIS KNOWNING THE OP SAID WEBER-
My pee brain was stuck on Carter and such..........

Absolutely not true... because of inherent flaws in castings, such as intake manifolds, carburetor passages etc. plus minor inconsistencies in needles & seats from both manufacturing defects and abuse... not to mention regular engine wear, it is extremely unlikely that carburetor balance would be identical on two or more jets.
That’s why engine analyzers like my antique Sun 1011 have a carb balance feature. For example, spark can be cut off to each half of the engine fed by their respective side of the carb. Adjust to best vacuum & note the rpm. When the remaining side is adjusted the readings should be nearly identical. Needle position within the seat is not expected to be the same.
In the decades I’ve been doing this I’ve never seen two properly adjusted, that are exactly in the same position.
Don’t shoot the messenger!

 

[mtnwhlr]

I think the carb is the least of your problems. That cap tells me you have coolant in your oil and you need to find out why. Run it that way and it will wipe out your bearings.

 

[Scout1067]

2. The emulsified oil under the cap - do you see any on your dipstick? I've seen that when close to oil change and the grommet for my pcv was dry-rotted and no longer sealing. Change your oil, let some seep out before removing the dipstick and look for any milky or chocolate oil. If none you don't have to worry about cracks or gaskets leaking. Be sure your pcv valve plumbed to manifold vacuum on the port. You shouldn't be getting oil blowing into the air cleaner except possibly at full throttle on a worn engine.


Edit - I just looked at your pictures, looks like your pcv is going to the air cleaner. That line should be going to manifold vacuum below the carb. You also need a way to get filtered air into the engine. A filtered breather at the back of the valve cover or a port from the air cleaner would work. This would also contribute to the condensation/milky oil on the filler cap, especially short trips as LG mentioned.

The oil on the dipstick is clean with no milkyness or frothing. It hadn't even occurred to me that the PCV line was run incorrectly. According to what i was told the new Carb was installed by a shop, one would think they would not mess that up. You are absolutely right that it should be running into the manifold. I looked it up in the TSM I downloaded off oljeep Collins' page. I will fix that today and I ordered a breather filter but that will take a week or so to get here since I order from the US and have to have it shipped to an APO, luckily Autozone ships to APO's for free.

That does however beg the question of what if anything is supposed to be connected to the port on the Carb that the PCV hose is currently connected to. I think for now I am just going to plug it and see what happens. I will post an update to this thread when the filter gets here and I get it put on. I am going to move the PCV hose before that as it should at least stop the oil from blowing into the carb itself. I also cleaned out the inside of the air filter housing so I can check this afternoon to see if that at least alleviated the problem.

 

[JeffP]

The oil on the dipstick is clean with no milkyness or frothing. It hadn't even occurred to me that the PCV line was run incorrectly. According to what i was told the new Carb was installed by a shop, one would think they would not mess that up. You are absolutely right that it should be running into the manifold. I looked it up in the TSM I downloaded off oljeep Collins' page. I will fix that today and I ordered a breather filter but that will take a week or so to get here since I order from the US and have to have it shipped to an APO, luckily Autozone ships to APO's for free.

That does however beg the question of what if anything is supposed to be connected to the port on the Carb that the PCV hose is currently connected to. I think for now I am just going to plug it and see what happens. I will post an update to this thread when the filter gets here and I get it put on. I am going to move the PCV hose before that as it should at least stop the oil from blowing into the carb itself. I also cleaned out the inside of the air filter housing so I can check this afternoon to see if that at least alleviated the problem.

That is great news! Pressure test the cooling system just to make sure there are no internal leaks.
The PCV (Positive Crankcase Ventalation) valve is a good thing and should be kept functioning.
Generally the inlet side protrudes into the crankcase via the block or valve cover and most often held in place with a rubber grommet.
The exit side has a 3/8”-1/2” hose attached that runs to manifold vacuum... generally at the base of the carburetor.
The “vent” can be as crude as an oil breather cap, or the more sophisticated type that is fed from a hose from the crankcase to the air cleaner. This system filters outside air prior to entering the crankcase.
In other words... air is drawn into the vent, then sucked out by the PCV valve and burned during regular engine cycles.
Besides reducing emissions, it also helps eliminate gas fumes from building up inside the block. Not blowing yourself up is a nice little safety feature.
At any rate it is a simple system that works and is extremely easy to maintain. Don’t plug thehole, hook it up the way it should be.

 

[Lumpy Grits]

Absolutely not true... because of inherent flaws in castings, such as intake manifolds, carburetor passages etc. plus minor inconsistencies in needles & seats from both manufacturing defects and abuse... not to mention regular engine wear, it is extremely unlikely that carburetor balance would be identical on two or more jets.
That’s why engine analyzers like my antique Sun 1011 have a carb balance feature. For example, spark can be cut off to each half of the engine fed by their respective side of the carb. Adjust to best vacuum & note the rpm. When the remaining side is adjusted the readings should be nearly identical. Needle position within the seat is not expected to be the same.
In the decades I’ve been doing this I’ve never seen two properly adjusted, that are exactly in the same position.
Don’t shoot the messenger!

I have seen plenty that were-
I have found it to be the most critical, for the balance to be in Carter made carbs, whether they were OEM(1960's M0-Par), or after market.
LG

 

[Scout1067]

I rerouted the PCV line from the air filter to the intake manifold yesterday morning and cleaned out the inside of the oil cap and air filter housing. Since my jeep is not a weekend car but the one I drive to work every day I put about 35 miles on it yesterday. I also stopped by my local shop and bought the right size hose and hose clamps since they had a 1/2” hose where a 3/8” was all that was needed.
I replaced the hose this morning and took the opportunity to check the cap and air filter housing, both are clean as a whistle. All I am waiting on now is the breather filter but Autozone says it shipped yesterday so it should be here abut this time next week. Thanks again to R717 for pointing me to the PCV line. I cannot say how glad I am it is a simple fix instead of replacing the Head.
The below pictures are the cap and air filter this morning without me doing anything other than looking at them.