Engine Engine Stalls on Rocky Inclines

[mjclimber]

Hello,
I just joined this forum and I'm looking forward to sharing and learning from you all. I acquired a '75 CJ5 with a AMC 258 i6 / 4.2l , 3 speed manual about 18 months ago. It has 105K miles and runs good for a 50-year-old original jeep. However, if I try to climb a fairly rocky 4WD trail, it will flood out as soon as the jeep hits a moderate pitch angle. I believe this is a problem with carbureted engines, but I suspect it should handle a 4WD trail a little better.
It has a AMC 258 i6 / 4.2l with a Weber 1 barrel, and I fuel is spilling over the bowl in a pitch situation. In addition, it seems the AMC 258 i6 / 4.2l is a little low on power (although it's improved after adjusting the ignition timing).
I've read some threads on this problem where people recommend a MC 2100 carb, which is a 2 bbl, and I have a 1bbl manifold. So, my dilemma is whether to change the intake to a 2bbl and go with the MC 2100 or to try a 2bbl to 1bbl adaptor plate.
It appears the exhaust manifold is bolted to the intake manifold and I'm having trouble finding an intake manifold that will fit, without changing the exhaust manifold.
Does anyone know what the original stock carburetor was? I think my current Weber was added at some point.
Just looking for any similar experiences or recommendations from the group.
Thanks very much!
MJ

 

[j6824]

Stock was most likely a Carter YF, which was a headache all its own

I ran a 2100 on mine before I switched over to the Sniper

Got mine as a kit off Ebay from Gronk...came with the intake adapter, gaskets, linkage...came pre-tuned

He was one of the few that machined the adapters back then, but there are quite a few out there now: (Link)-> Motorcraft 2100 Carburetor Jeep for sale | eBay -<

 

[CJ]

Hello,
I just joined this forum and I'm looking forward to sharing and learning from you all. I acquired a '75 CJ5 with a AMC 258 i6 / 4.2l , 3 speed manual about 18 months ago. It has 105K miles and runs good for a 50-year-old original jeep. However, if I try to climb a fairly rocky 4WD trail, it will flood out as soon as the jeep hits a moderate pitch angle. I believe this is a problem with carbureted engines, but I suspect it should handle a 4WD trail a little better.
It has a AMC 258 i6 / 4.2l with a Weber 1 barrel, and I fuel is spilling over the bowl in a pitch situation. In addition, it seems the AMC 258 i6 / 4.2l is a little low on power (although it's improved after adjusting the ignition timing).
I've read some threads on this problem where people recommend a MC 2100 carb, which is a 2 bbl, and I have a 1bbl manifold. So, my dilemma is whether to change the intake to a 2bbl and go with the MC 2100 or to try a 2bbl to 1bbl adaptor plate.
It appears the exhaust manifold is bolted to the intake manifold and I'm having trouble finding an intake manifold that will fit, without changing the exhaust manifold.
Does anyone know what the original stock carburetor was? I think my current Weber was added at some point.
Just looking for any similar experiences or recommendations from the group.
Thanks very much!
MJ

Unfortunately the Webber carb, while being popular is a poor choice for off-roaders. It's great for performance but not so great once off camber angles are large due to the float pivot location.

 

[Belizean]

I had a Weber on my 4 cylinder. Original carb was soon after I bought new. I went to the Weber. I live down south in gulf coast area and the Weber was a vast improvement down on flat areas. When I went in climb conditions it worked going up hill ok, but if I stopped, I had the same problems. Stalling and flooding. I got a AMC 258 i6 / 4.2l and a Sniper also so I can go to places like Moab and Colorado.

 

[Manic Mechanic]

Welcome aboard.

Original would have been a Carter and as stated it's . I was running a MC 2100 as well for years using a Mr gasket adapter plate. As others I switched to a sniper EFI (2300) so I didn't have to change anything.

As far as your other question yes the intake and exhaust share bolts but you can remove one without removing the other.

The only thing you really need if you switch to a 2100 is an adapter plate to go from 2 barrel to 4. (The intake is already 2 barrel but the 2100 is standard square bore. 4 barrel set up) the other thing is a throttle cable for a V8 CJ so that you can eliminate all the linkage.

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[TSB8C]

EFI...

 

[mjclimber]

Stock was most likely a Carter YF, which was a headache all its own

I ran a 2100 on mine before I switched over to the Sniper

Got mine as a kit off Ebay from Gronk...came with the intake adapter, gaskets, linkage...came pre-tuned

He was one of the few that machined the adapters back then, but there are quite a few out there now: (Link)-> Motorcraft 2100 Carburetor Jeep for sale | eBay -<

Thanks very much for the info and link. Very helpful!

 

[mjclimber]

Welcome aboard.

Original would have been a Carter and as stated it's . I was running a MC 2100 as well for years using a Mr gasket adapter plate. As others I switched to a sniper EFI (2300) so I didn't have to change anything.

As far as your other question yes the intake and exhaust share bolts but you can remove one without removing the other.

The only thing you really need if you switch to a 2100 is an adapter plate to go from 2 barrel to 4. (The intake is already 2 barrel but the 2100 is standard square bore. 4 barrel set up) the other thing is a throttle cable for a V8 CJ so that you can eliminate all the linkage.

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Thanks for the info and photos! I realize that an EFI conversion would be the best option, but cost is a factor. I will switch to the MC2100 and the adapter plate. Great point on the throttle cable as well!
MJ

 

[mjclimber]

I had a Weber on my 4 cylinder. Original carb was soon after I bought new. I went to the Weber. I live down south in gulf coast area and the Weber was a vast improvement down on flat areas. When I went in climb conditions it worked going up hill ok, but if I stopped, I had the same problems. Stalling and flooding. I got a AMC 258 i6 / 4.2l and a Sniper also so I can go to places like Moab and Colorado.

Thanks for the info! Sounds like the Weber is the wrong carb for off roading. I'll make the switch to a MC2100 and plan to repost the results.

 

[Manic Mechanic]

Aim for one off of a 72 bronco with the 302. It will have the 1.08 ventri best setup for the AMC 258 i6 / 4.2l . get an original unit. There are cheap repops on Amazon for a 90 bucks and while they work they don't last long and they're not a true 1.08 ventri

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[mjclimber]

Aim for one off of a 72 bronco with the 302. It will have the 1.08 ventri best setup for the AMC 258 i6 / 4.2l . get an original unit. There are cheap repops on Amazon for a 90 bucks and while they work they don't last long and they're not a true 1.08 ventri

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I am finding a lot of reman carbs (Uremco and Tomco), and did find a MC2100 on ebay. However, these carbs don't specify the venturi size. Do you by chance have any recommendations on where I might find the MC with a 1.08 venturi?
I realize this is very specific, but I want to be sure and get the correct carb.
Thanks again!

 

[CJ]

I am finding a lot of reman carbs (Uremco and Tomco), and did find a MC2100 on ebay. However, these carbs don't specify the venturi size. Do you by chance have any recommendations on where I might find the MC with a 1.08 venturi?
I realize this is very specific, but I want to be sure and get the correct carb.
Thanks again!

If you get the actual carb number you can tell the venturi size.
If it's an actual MC 2100 it is stamped on the side. If it's a knock off it is not.
Also if it's 1.08" that was for the 302.

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Motorcraft 2100 Venturi Size

www.carburetor-parts.com

 

[mjclimber]

If you get the actual carb number you can tell the venturi size.
If it's an actual MC 2100 it is stamped on the side. If it's a knock off it is not.
Also if it's 1.08" that was for the 302.

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Motorcraft 2100 Venturi Size

www.carburetor-parts.com

Awesome! Thanks very much.

 

[flyn hawaiian]

Hello,
I just joined this forum and I'm looking forward to sharing and learning from you all. I acquired a '75 CJ5 with a AMC 258 i6 / 4.2l , 3 speed manual about 18 months ago. It has 105K miles and runs good for a 50-year-old original jeep. However, if I try to climb a fairly rocky 4WD trail, it will flood out as soon as the jeep hits a moderate pitch angle. I believe this is a problem with carbureted engines, but I suspect it should handle a 4WD trail a little better.
It has a AMC 258 i6 / 4.2l with a Weber 1 barrel, and I fuel is spilling over the bowl in a pitch situation. In addition, it seems the AMC 258 i6 / 4.2l is a little low on power (although it's improved after adjusting the ignition timing).
I've read some threads on this problem where people recommend a MC 2100 carb, which is a 2 bbl, and I have a 1bbl manifold. So, my dilemma is whether to change the intake to a 2bbl and go with the MC 2100 or to try a 2bbl to 1bbl adaptor plate.
It appears the exhaust manifold is bolted to the intake manifold and I'm having trouble finding an intake manifold that will fit, without changing the exhaust manifold.
Does anyone know what the original stock carburetor was? I think my current Weber was added at some point.
Just looking for any similar experiences or recommendations from the group.
Thanks very much!
MJ

My 85 CJ7 with AMC 258 i6 / 4.2l had a clifford intake 4bbl with a 390 holley 4bbl. and headers. I didn't have to much problems with it.

 

[NP435]

Hello,
I just joined this forum and I'm looking forward to sharing and learning from you all. I acquired a '75 CJ5 with a AMC 258 i6 / 4.2l , 3 speed manual about 18 months ago. It has 105K miles and runs good for a 50-year-old original jeep. However, if I try to climb a fairly rocky 4WD trail, it will flood out as soon as the jeep hits a moderate pitch angle. I believe this is a problem with carbureted engines, but I suspect it should handle a 4WD trail a little better.
It has a AMC 258 i6 / 4.2l with a Weber 1 barrel, and I fuel is spilling over the bowl in a pitch situation. In addition, it seems the AMC 258 i6 / 4.2l is a little low on power (although it's improved after adjusting the ignition timing).
I've read some threads on this problem where people recommend a MC 2100 carb, which is a 2 bbl, and I have a 1bbl manifold. So, my dilemma is whether to change the intake to a 2bbl and go with the MC 2100 or to try a 2bbl to 1bbl adaptor plate.
It appears the exhaust manifold is bolted to the intake manifold and I'm having trouble finding an intake manifold that will fit, without changing the exhaust manifold.
Does anyone know what the original stock carburetor was? I think my current Weber was added at some point.
Just looking for any similar experiences or recommendations from the group.
Thanks very much!
MJ

I run a 2150 on a stock 2 barrel manifold with zero issues at extreme angles. I bought the manifold from Dead Jeep parts.com. I have that phone number should you want it contact me.

 

[Rockhpr]

I had the AMC 258 i6 / 4.2l with the carter for numerous years dealing with the headaches. I used a manual, dial down, in line pressure regulator as a temporary fix, (4 years). It worked but was not convenient. I used it in Moab for a few years, having to dial it down before I go up a steep hill and turn it back up before going down the next hill. I used this until I could put in fuel injection. It was a cheap, easy temporary fix.

 

[Manic Mechanic]

My 2100 was fantastic on and off road even very steep inclines. Just got tired of screwing with it with the ethanol in the fuel constantly messing it up

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[mjclimber]

Hello,
Just an update on my AMC 258 i6 / 4.2l carb conversion... I bought the MC 2100 carb to replace my 1 barrel Weber, and also got an adapter plate for the MC 2100.

Now I have run into an issue where the bolts on the original adapter on the 1 barrel manifold do not align with the MC 2100 plate. The new carb bolt holes measure 3.25 inches center to center (on the new adapter) and the existing manifold adapter measures 3.5 inches center to center.

I have not had any luck finding a new adapter for the manifold, and I also don't really like the idea of having 2 adapters between the 1 barrel intake and the new 2100 carb.

I think the best option would be a 2 barrel intake. However, I'm having some trouble finding a replacement 2 barrel intake. (Some considerations such as the bolting to the exhaust manifold and water ports on the newer MY manifolds?)

I appreciate any ideas the group may have on how to remedy the new carb conversion.
Thanks much!

 

[mjclimber]

I run a 2150 on a stock 2 barrel manifold with zero issues at extreme angles. I bought the manifold from Dead Jeep parts.com. I have that phone number should you want it contact me.

Thanks for the info! I checked on the Dead Jeep Parts website but the site isn't working well (maybe I'm on the wrong site?) If you have a ph. number or link, that would be great.
Thanks!!

 

[Manic Mechanic]

Amazon.com

This should be the one you need. Post a picture of your intake without the carb on it. Should look like this.

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