Swap mc 2150 to 225...not running

I just finished installing a rebuilt mc2150 onto my 225 with the mr. Gasket adapter #1937. It all came together fine but the jeep won't start. The carb is the 1.08 Venturi size, and is from an '84 ranger. I removed a few solenoids that I think I won't need, and converted to manual choke. My biggest question is, what vacuum ports can I plug? I have the major ones figured out:
big one at the rear of the base to a valve cover, air filter on other side of engine
Small one under/just forward of choke to vac. advance
Bowl vent open
Small one behind carb to vacuum choke canister....do I need this with manual choke conversion?
EGR/emissions one at front drivers corner...plugged because it's a smog exempt year.
Power valve....to plug or do I hook this one to something? This one has me confused.

When I've tried to start it, I get nothing other than a massive tailpipe backfire after a while because I am activating the throttle/accelerator pump by hand. Lastly, are there any good rebuild guides out there? My idle mixture screws were very different from each other when I got it...1.75 turns out on passenger and 3.5 turns out on driver....is there a good start point like 2 turns out?

 

Power valve on a 2150 requires a manifold vacuum connection.

 

Thanks. What about the number of turns on the mix screws? Can they be so different? I know 2-2.5 turns out is pretty common for 2G's. What are other folks running with 2100/2150 on their 225's?

 

The idle mixture screws have no effect above about 1000 RPM. After that, the mixture is controlled by the main jets.

Adjust to best lean idle. Turn the screws in together 1/4 turn at a time until the RPM drops noticeably. Then back off 1/4 turn.

Alternately, adjust for maximum vacuum at idle (but this is not what Jeep recommends).

 

Generally speaking, I've never had a 2100/2150 that wouldn't run, with the initial idle screws setting done as "run the screws into the seats, and back them off 1 1/2 turns" That's always been my initial setting with 2100/4100 series motorcrafts anyway....

 

Well after much frustration, turned out my flamethrower coil was bad (thought they were supposed to be good for a long time?). I replaced it and the jeep wanted to fire right up. The problem now is that it only runs with the accelerator pump....not the idle circuit. I pulled the unit with all the idle tubes and checked the gasket and it was fine. The tubes seemed clear as well when flushed with carb cleaner. I also blew out the main jets while the horn cover was off. Any idea why the idle circuit is not letting the jeep idle? I've tried mix screws from 1.5 to 3.5 turns out...it maybe had a little better/longer run time off of a single throttle pump actuation at the 3.5 end of that range, but the motor still dies soon after my hand leaves the throttle.

Could this be because of a manifold vacuum leak somewhere? Is this a case where I need bigger jets? This carb came off a 2.8L ford ranger.

 

If you look at any of the manuals on the oljeep.com site, there is a description of the circuits in the 21xx carburetor. Your Ranger carb should be the same in how it functions, even though it's a smaller carb. I would not expect a carb for a 2.8L to work well on a 3.8L engine without some changes. The main jet size will definitely be too small, and the idle circuit feeds through the main jets. Just as a WAG, I would expect you'd need to go up in main jet size roughly in proportion to the increase in displacement. There is no simple relationship between pipe diameter and flow, so I'd just guess that you need to increase the jet size somewhere between the increase in area and the increase in diameter of the hole in the jet, between 17% and 36%. So if you have a 45 main jet size now, you need somewhere between a 53 and a 61 jet to keep the same air-fuel ratio with this carb on the 3.8L engine.

My guess is that you're just too lean to idle ... unless you have another problem.

If there is something wrong, the most likely problem is a big vacuum leak downstream of the carburetor. This assumes the carburetor is assembled correctly, and you don't have a big hole in the power valve (common - often a backfire will blow out the power valve). For the idle circuit to work, you need the transfer slots partly covered by the throttle plate, and there has to be enough vacuum at that point to pull the fuel through the idle ports. By the time the throttle opens enough to uncover the transfer slot, the idle ports no longer provide fuel and fuel now comes through the booster venturis.

Realize that the 2.8L carb may have a different booster venturi, meant for the smaller displacement - even though the venturi is the same size as the V8 carbs. So you may end up somewhat restricted compared to the V8 carbs. The booster venturi of the 21xx works so well to make vacuum that the V8 carbs are a popular app for smaller engines - but you need strong vacuum for emissions control, and this carb likely has a more restrictive booster to provide additional vacuum.