2100 Jets...

[007]

So I have an MC2100 / 1.08 / 6DA2J carburetor. I rebuilt it 2 years ago and have been running it ever since, but I believe I'll need a jet change for here at my home altitude of 414 feet as I run pretty rich. TeamRush and I are going to work on this Saturday, but we believe a jet change is more than likely.

I haven't pulled it apart yet, but I'm not sure what jets I need or what was even stock? I'll bet that what I have is stock as everything else on this Jeep has been so hopefully they are and we shall see. Does anyone know what I should expect as "stock" jets?

I also need jets for Colorado as since I'm rich here, I'm EXTREMELY rich there (gave OldJeepLady and Mriplaybass watery eyes as they followed).

The man that owns the service station in Ouray says that you need to do two things to make your stock Jeep run right there - add 1 degree of advance for every 1000' of altitude and drop two jet sizes from whatever you're using at sea level to 1000'.

He said to basically drop the smaller jets in and bump it 10 degrees so you'd be good from 7800 (Ouray) to 13,000+ at the trail peaks.

 

[007]

UPDATE - looks like the FSM says 48's are stock....


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[oldjeeplady]

Where did you find that info? Page 1J-32 FSM has a spec chart for the 2100. It lists a 9DA2J venturi 1.08 main jet of 44. We just rebuilt our 2100 ..it had 49. So am I reading this chart wrong? I couldn't find the number you listed 6DA2J… .I did find it on carb sites though.

 

[oldjeeplady]

Sorry… I was looking at '79 FSM. The first number in the code is the year of manufacture. I missed that…

 

[007]

No prob - I think you might have the 2150 carb which has the altitude compensation...not sure how that works, but if it does it would be nice.

I got my info from the 77 FSM and I believe my year was the last year for the 2100, or at least it was for my tag ID.

 

[IOPort51]

My 2c


If I lived in the mountains I would set up for the mountains but I do not. I think I am running 46s in my 2100 on a AMC 258 i6 / 4.2l . It may run a bit rich at 13000 but so what. It just smells a bit when the wind is just right. Lean it out too far and engine temp can rise, not a good thing, I do also have an MSD 6 ignition that I think would light a pile of wet saw dust that may enter into the equation. I think there is a possibility that rather than being "rich" you may just not be burning everything you pull into the cylinder. I would prefer to think of the situation as not enough air rather than too much fuel. Short of a turbo charger, there is an idea, I don't think you can get the performance , at altitude, you think you will get by reducing the fuel supply.

 

[007]

My 2c


If I lived in the mountains I would set up for the mountains but I do not. I think I am running 46s in my 2100 on a AMC 258 i6 / 4.2l . It may run a bit rich at 13000 but so what. It just smells a bit when the wind is just right. Lean it out too far and engine temp can rise, not a good thing, I do also have an MSD 6 ignition that I think would light a pile of wet saw dust that may enter into the equation. I think there is a possibility that rather than being "rich" you may just not be burning everything you pull into the cylinder. I would prefer to think of the situation as not enough air rather than too much fuel. Short of a turbo charger, there is an idea, I don't think you can get the performance , at altitude, you think you will get by reducing the fuel supply.

Well I hear you, and I understand. I hear people say all the time that "if it runs at home it'll run in the mountains" and that's true - it will, and mine did.

The problem I have is that with my gears I need it to run much better than merely acceptable. It needs to be on top of its game to handle the highway without overheating. I don't mind rich, but too rich coupled with a lack of appropriate advance and you have issues like I did. Poor advance and too much fuel necessitated it being floored and thus zero vacuum, thus only centrifugal advance and not enough of it. All that equals increase engine heat. The times I had issues with overheating were the times after spending 10mins on the highway. When I didn't do that (Yankee Boy) or let it cool before - I could run all day in low range with the RPM's high enough to keep vacuum and advance.

 

[Jimbos76cj]

My Junk yard 2150 ended up having a 53 jet and a 48 in the carb. I replaced them with a new set of 46's and after a few trips around the block it cleaned up the sooty plugs. If you havent pulled the top off your carb yet I would start with that to see where you are at. Like rear ends I wouldnt trust a tag to tell me any thing about the carb that can be swapped.

 

[007]

My Junk yard 2150 ended up having a 53 jet and a 48 in the carb. I replaced them with a new set of 46's and after a few trips around the block it cleaned up the sooty plugs. If you havent pulled the top off your carb yet I would start with that to see where you are at. Like rear ends I wouldnt trust a tag to tell me any thing about the carb that can be swapped.

I did and it did have 48's in it. I went to 46's and all seems well. I have 45's and 44's as well in case I need them when I get out there. I do need to order a couple of spare top gaskets but beyond that I'm good to go I think...