running waaaaay too rich!

i recently pulled my carbs to clean the starter enrichment circuit out (the rest of the carbs were surprisingly shiny, but i did a bit of cleaning just to make sure!) then i did a bench sync, threw them on, tried to sync them, and then noticed that it was running waaaay too rich. when i pulled the throttle, it would bog for a second till 2000 rpm, then black smoke shot out of the exhaust and it would race up to 6000 rpm and slowly trickle down to where it was. the plugs are all covered with a thick soot which i can clean most off with cleaner and steel wool.

i'm planning on pulling them again today to peek inside and make sure nothing is stuck, any suggestions on what else to look for?

fall is fast approaching in my world and four wheels just don't move me any more!

 

Do a forum search for "old school carb cleaning" and "clunk test."

 

Where did you set your mixture screws? About 3 turns out is usually a good starting point.

 

i had a verrrry sneaky suspicion that it was the clunk test! that shall be the first thing i check when i pull the carbs!

as for the mix screws, i didn't adjust them since the settings seemed perfect before the cleaning. i did, however, check a couple of them, and they're right at 2 1/2 turns.

any other ideas? the garage where i work on the xj is 20 miles away with no internet access, so i try to get a full days game plan of troubleshooting before i venture out there

 

just got back in, and i polished the diaphragms till they positively sparkled. they passed the clunk test with no problems whatsoever! i also checked the float levels for all the carbs, and none of them seemed even close to being too high.

however, once i reinstalled the carbs and fired it up out shot the black smoke again! it didn't quite seem as bad, however. could just be me seeing what i want to, though.

any ideas out there as to what i should check next?

 

It is common for a float valve to stick after installing the carbs. Tap the sides a few times with the handle of a screwdriver and the black smoke may be gone. It is also possible that the petcock is leaking and dumping extra fuel into the #3 intake. #3 because that is the standard intake for the petcock vacuum line to be attached to. If only #3 then the black smoke will come out of the right exhaust. If a lot of fuel is being pulled in then it can cross over to #2 via the YICS port and push black smoke out the left exhaust.

 

thanks blue! i'll tap the hell out of the carbs first thing tomorrow morning! i don't think my petcock is leaking, it didn't leak at all before i pulled the carbs...then again, maybe it developed a small leak during the week i had the carbs pulled.

 

update:

discovered yesterday what the problem was after all! while putting the carbs back together i had installed the air/fuel jets backwards inside the diaphram bowl! rickcomatic briefly mentioned it in another forum post.

just goes to show you, make sure the carbs are facing the same way while putting them together as they were when you took them apart!

now to just fine tune them this afternoon and i'll be ready to roll!

 

Interesting - I made a diagram for mine - I was sure I would do the same thing.