a few MC2100 questions

a few MC2100 questions

stoney bones

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michigan
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81 CJ7

258ci, mc2100 ,SR4 trans, dana 300 Tcase, dana 30 front, amc 20 2 piece rear
I've just replaced my carter bbd with the mc2100 as some of you may already know.

it started right up and will run. however it was idling up then idling down slightly...as if a wave. i switched a couple vac lines and it now runs steady. but, after driving down the road about a mile i was coming to a stop sign. it died while downshifting into first. re-started no problem but kinda had to give it a little gas to keep it from stalling again. i turned around went back to the drive way and while down shifting into third it started popping. not real loud gun shot sounding but just quieter, quicker pops and then again while down shifting into 1st to turn into the driveway it died.


it restarts and will run fine other than that.

im in the midst of changing it over to a rear pull throttle as to be more efficient and get rid of the bracket and arms. in its current setup there is no free play and the movement is not very smooth feeling.

any ideas where to start?
 
vacuum leaks, look for them.
 
would it have been a good idea to use a RTV silicone on all the gaskets for mounting the carb to the adapter to the manifold?
 
I would double check Timing, Idle, and mixture of carb... Also as IO said vac leaks...

:chug:
 
about my vac line.... the carter has the pcv hose coming into and one vacuum line from the disro. thats it. the other vac line blocked off on the carter.

now on the mc2100 there is no where for the pcv hose to goto so i assume i can let route that to the bottom and let it hang or remove the hose and attatch a breather of sorts? is that correct?

then the vacuum line coming from the distro seems like it is supposed to goto the port on the carb that goes into the air assembly. is that correct? if not there is only one other place to stick it.
 
You should find a place for the PCV. there is a place on the side of the intake manifold if there is no place on the carb. you man have to put a nipple there but there should be a 1/4 inch pipe taped hole, maybe with a plug in it?
 
that is a possibility, I was thinking more like this.
 
mc2100vacuumdiagram.jpg
 
Same thing, only even more simplified

vacuum_setup.jpg
 
vacuum leaks, look for them.


What he said ^^^


would it have been a good idea to use a RTV silicone on all the gaskets for mounting the carb to the adapter to the manifold?

No, try to stay away from silicone around your carb, the gasoline will eat away at it.

Also, what kind of adapter plate did you use? I had the very same issue a year or so ago, the advance adapters plate I bought never would seal right, I ended up buying a more expensive one, don't remember who makes it now though, but I bought it from Summit.
 
thanks for the diagram. i see how it should be now. just need to fix the pcv.


i dont know what mfg the adapter is. it came with the carb from the guy that rebuilt the 2100. when i took it off i noticed in one of the 4 corners a nice imprint where you could tell it made a seal then basically everywhere else didnt look the same. if that makes any sense.
 
the PCV is manifold vacuum and the dist. is ported vacuum:D
 
If its a mrgasket brand it will have an indentation where the logo and part number is stamped and it will cause a vac leak to fix that you have to take it off and fill the holes with jb weld then file it flat. I had a short write up on this (long story short it got deleted because of an argument) anyhow check that.

Sent from my DROID2 using Tapatalk
 
thanks for the advice friends.

the person i got the carb from instructed me to use the red high temp rtv all over everything if there was a vacuum leak.

im a sitting duck at the moment until i run into town and get some gaskets.


just out of curiosity, is there such thing as a fuel safe rtv?
 
noted. will do. or not do, depending how your looking at it. i picked up a can of starting fluid so after its all assembled again i can check more thoroughly for any leaks.
 
thanks for the advice friends.

the person i got the carb from instructed me to use the red high temp rtv all over everything if there was a vacuum leak.

im a sitting duck at the moment until i run into town and get some gaskets.


just out of curiosity, is there such thing as a fuel safe rtv?

I had to use permatex 2 on my gaskets to get them to seal right. The package says its safe to use around fuel and oil.
 
well...went and picked up a mr gasket kit that had 4 sheets of different types of gaskets. i used the thinner cork type material on both sides, bolted it all up, hooked things here and there and she seems to run great now. even sprayed starting fluid around the base of the carb and adapter plate and it all seems sealed up.

no more popping, no more stalling. i think i have the idle up a tit too high and i need to get some more free play in the throttle cable but other than that i can tell its running a lot better than with the BBD on there.


thanks for the help folks, appreciated as always.
 

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