MC2100 jet question

[lah2420]

After getting the top and doors off, I've been smelling a strong, rich exhaust odor. More so than when I had a weber on the motor. I thought I would check to see what size jets the MC2100 has in it. Both of them have been stamped very off center as to the size. I have what looks like the top of a triangle, which I assume could be a 4, a small circle that could possibly be the top of an 8 or 9, and what looks like the top of an "F". Did the Ford jets have numbers followed by an "F"? Is there any other way to tell the size?

 

[lah2420]

Answered my own question. I found a site from 2002 that says:

"1. You might try the auto parts stores for Ford jets or, the dealer or, a
carb. rebuild shop.
2. Yes, the numbers on the jets are like: 48F, 49F, 50F, etc. The bigger
the no. the larger the hole in the jet for the fuel to pass."

So now I know I have either 48s or 49s in there. I'm going to try to find some size 46 and 47 jets and see if they make any difference.

 

[wm69]

I've got 47's and mine runs rich. I'm in Fayetteville so not sure where in AR you are but we ought to be about the same amount above sea level. I was going to try 45's or 46's, but I wanted to be sure I had the right power valve first. I used the one that came with the carb rebuild kit....

 

[lah2420]

I'm down in Texarkana. Not but a couple hundred feet difference probably. I think mine has 49s in it. I've ordered some 46 and 47s. If that doesn't do it, I'll try the power valve too. I'll have to check to see which one I need though.

 

[wm69]

Let me know what works for you down there. My jeep is buried in golf clubs and my kids floaties at the moment so I haven't driven it in a couple of weeks.

 

[lah2420]

Just got back from vacation trip, so I should be driving it all this week. I've put in the 46 jets and will fill up and see what happens this week.

 

[wm69]

Just got back from vacation trip, so I should be driving it all this week. I've put in the 46 jets and will fill up and see what happens this week.

Where did you get your jets? I've had a place called swapsupply in my computer for months with the intent of getting jets and when I finally decided to order some I got an email that the owner has passed away and the business is closing. I've had the guys site in my computer for about a year and this thread got me moving on it again only to get stumped.

 

[lah2420]

I got them from swapsupply. But I ordered them via Ebay. He must have just passed away because mine were delivered the first of this month and, you're right, his account has nothing for sale at this time. You might search for part numbers. Mine were 120-4-046 and 120-4-047. They might have a dot in front of the jet size, like 120-4-.046.

 

[wm69]

I got them from swapsupply. But I ordered them via Ebay. He must have just passed away because mine were delivered the first of this month and, you're right, his account has nothing for sale at this time. You might search for part numbers. Mine were 120-4-046 and 120-4-047. They might have a dot in front of the jet size, like 120-4-.046.

aaaaaaaah. Why didn't I order those things while I could. I searched the net for 2 hours last night and couldn't find anyone who sold motorcraft jets. Anyone know of anywhere else to get them. i guess I'll email ermanhap guy who sells the MC2100 conversion and see if he'll sell me some.....

Have you driven the Jeep with 46's in it yet? When you do let me know how it goes. I've got three Jeeps that I think will eventually get a MC carb and I was going to order 2 sets of 45's, 2 sets of 46's, and put the 47's I have now onto my Jeep in my sig that has upgraded ignition/exhaust etc.

 

[lah2420]

Swapped the jets for 46s last weekend. I drove it all week, which only amounted to about 80 miles. No difference that I could notice in power except that it is a little cold natured. I guess the larger jets pumped enough gas into the venturi that it overcame the choke. It runs fine once the choke opens fully. There is only a minimal exhaust smell now. I don't smell like a tailpipe after driving any more. The remaining smell may be due to the previous owner removing the cat and disabling the EGR. I don't know if mileage increased or decreased yet, but I just like not having the smell now.

 

[wm69]

Keep me updated. I asked Ehrmann what he would suggest as far as jet size/ power valve size and am waiting for a response from him. I drove my Jeep today and i smell like exhaust BAD.

 

[wm69]

Hey lah, how are those 46's working for you?
The ebay guy recommended 48's at my altitude, and said I probably have the wrong power valve in there. Instructions were to hook up a vacuum gauge and divide the reading (at idle) by 2, then subtract 2 from that number, and that's the proper power valve.
I drove the jeep around yesterday and it just smells like crud, not to mention the nice clouds of black smoke when I start it hot.

Also, anybody know where to get a cheap vacuum gauge and where to hook it up on my Jeep?

 

[lah2420]

Other than being somewhat cold natured in the morning, it's running great. There is still a little exhaust smell that may be because of the power valve. I didn't know how to check for what I needed. Now, it's going to be fun finding one too. I got my vacuum gauge/fuel pressure gauge from Oreilly's for about $25. I still haven't checked my mileage to see if that has improved. I'm assuming it has since I just started my 3rd week on this tank and usually filled up every 2 weeks.

 

[wm69]

Other than being somewhat cold natured in the morning, it's running great. There is still a little exhaust smell that may be because of the power valve. I didn't know how to check for what I needed. Now, it's going to be fun finding one too. I got my vacuum gauge/fuel pressure gauge from Oreilly's for about $25. I still haven't checked my mileage to see if that has improved. I'm assuming it has since I just started my 3rd week on this tank and usually filled up every 2 weeks.

ebay guy said to have it at idle (mine's at about 800 rpm, which he said was fine) take the vacuum reading, divide that number by 2, then subtract 2 from that.
Vacuum reading 14 divide by 2='s 7
7-2=5
So you need a 5 power valve.
Holley power valves will work (from what I've been told) and are available about anywhere.

 

[lah2420]

I finally filled up and although the rich smell is much less, the gas mileage is about the same. I was hoping for a little improvement. Oh well, it IS a brick on wheels. I'm going to play with the power valve next. Mine pulls a hair over 16 Hg at idle. That figures to a 6 Hg. They only make it in a 5.5 or 6.5 Hg. As far as the Holleys working in the Ford, they are the exact same part number from Walker Products. I think Oreilly's can order it. At least they list it on-line.
I'm not sure what is in it right now. It's too much trouble to pull the carb to get to it unless I have the right part to use if I have to change it.

 

[wm69]

I finally filled up and although the rich smell is much less, the gas mileage is about the same. I was hoping for a little improvement. Oh well, it IS a brick on wheels. I'm going to play with the power valve next. Mine pulls a hair over 16 Hg at idle. That figures to a 6 Hg. They only make it in a 5.5 or 6.5 Hg. As far as the Holleys working in the Ford, they are the exact same part number from Walker Products. I think Oreilly's can order it. At least they list it on-line.
I'm not sure what is in it right now. It's too much trouble to pull the carb to get to it unless I have the right part to use if I have to change it.

Thanks for the update. Where did you hook the vacuum gauge up on the carb?

 

[lah2420]

I have a "Y" immediately under the carb that also runs to the front axle disconnect. It has a plug on one leg and I just plug it in there. All the ports on my carb are ported. I went to Oreilly's and ordered a 6.5 power valve today. Won't be here until Wednesday.

 

[wm69]

Drove mine to Siloam Springs today and the whole family smelled like exhaust when we got back...
I'll pick up a vacuum gauge in the next day or so and see what I get.
Thanks for keeping me updated. This is something I've been needing to do for awhile and I need to get it done and quite putting it off.

 

[wm69]

how are those 46's working for you? Just wondering if you ever got that PV put in. Ehrman told me I needed 48's if I have the right power valve, but I'm running rich at idle right now with 47's so I'm not sure what I want to do.

 

[lah2420]

I went back to 47s. It doesn't act as cold natured now. That was getting irritating. I put in a 6.5 PV at the same time. It had a 7.5. The only thing wrong now is that my clutch went out. Now I've got to wait until I have time to pull the transmission and fix or replace the clutch. Too many things going on right now to mess with it. Food plots, stand placement, and helping a kid work on his "new" house are taking up 25 hours a day on weekends and evenings. Maybe my boss will pay me not to come to work for a few weeks.