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first post...and naturally I have issues I need some help with. I have a new to me 82' Cherokee I picked up a couple of months ago....my problems are a little confusing,and difficult to describe.mostly I'm a diesel guy...if this were a cummins,i could have it at least diagnosed in a couple of hours.since this jeep has sparkplugs,and a tool of the devil,known as a carburetor,i'm a little stuck.

symptoms are as follows...#1, extremely hard to start cold.i can get it going after a lot of fooling around,and when it does,it idles fine,but rough.
#2 . when its warmed up,burp the throttle,and it will rev up fine,but upon throttle release,blows white smoke,which then clears up.slow release of throttle,results in no smoke.
#3 . the worst thing...when in gear,and brakes applied,any throttle to load it will cause it to run rough,detonate,and die. its undrivable right now.

things ive fixed...the previous owner said the carb was leaking...and wow,was it ever.the idle mixture screws were closed off.it was running on its own leaks! resealed carb,cleaned it out,unplugged one main jet,new float needle and seat,and some new gaskets , power valve and acell pump... found a huge number of vacuum leaks and plugged them.might have missed one...still searching.set the idle (750 rpm in park...625 in gear)

things I'm sorting...the symptoms kinda scream timing.the engine pulls 19"HG manifold at idle (750 rpm) this seems fine.the dizzy advances 5* at 10"HG,about 16* at 20"HG measured on vac pump guage.my timing lite says I'm at 10" mech advance at idle...after much fiddeling,i can say I'm getting about 35* advance at 2200...and it stops there.initial ramping of timing advance is rapid...I get a further 10* from static at 1450 rpm.
I've tried every timing setting I can think of,to no avail...the engine refuses to pull under load without bogging,detonating and then dies.i think I may have a number of issues timing and fuel related,that are compounding each other...what I'm doing now,is this....I'm going back to basics.I've set the engine to TDC on number 1 compression,and pulled the dizzy,so I can have a look at the advance springs etc...any advice beyond this would be helpful.

only other hint I can give ,is this engine ran on propane for some time before I got it...the timing values for lpg are rather different than gas,so i'll concentrate on getting the timing right for now.

Engine you have? Carnuck on here really good at setting up running on propane. Got mine up to 15mpg.

360...with 2150 2bl carb,possibly original,but rebuilt at least once before me by the tag...stock dizzy,likely original.

I just want to get it able to drive around the block right now...not interested in getting it back to propane.the PO stripped out all the LPG stuff,and went back to gas...I'm likely the 3rd or 4th owner,and everyone before me fiddled with something on this engine.

Off the bat I would guess your carb gaskets and seals are dried out if he was using it on a propane set up. Next check the timing it is definitely different on propane than gasoline also check the distributer for wear if the bushings are bad it can cause you to pull your hair out

If the engine was built for propane the compression should be slightly higher.

I believe that this 360 was/is factory...it was modded for propane external only.when I went through the carb,the power valve was leaking,and the accel pump diaphragm was cracked...it may have been used as a dual fuel setup,but not at all sure.

I went and ordered a reman dizzy...they are fairly cheap,and I needed a new pickup,anyway as I found that the old plug had cracked and exposed bare plug terminals to open air.i'll keep the old one for an emergency spare...another possibility-the way this thing runs,there is a fair chance the timing chain has slipped a tooth...I will test tomorrow. it would explain a complete inability to time it correctly.

Make for sure to use your old dizzy gear on the now dizzy! Trust me, the new gear that comes on the aftermarket one will not match up to your old cam gear.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Runcible_Spoon wrote: #1, extremely hard to start cold.i can get it going after a lot of fooling around,and when it does,it idles fine,but rough.

What is your cold temp? 50 or below 32?

you really need to pump the skinny 2 or 3 times to dump gas... otherwise try to dump 1/4 cup of gas down the carb throttle plate, or starting spray, that will give you an idea if the carb bowl is dry, so you have to crank the engine to prime the mechanical fuel pump. Seems like you pull the carb off and nothing weird was found...

Runcible_Spoon wrote:#2 . when its warmed up,burp the throttle,and it will rev up fine,but upon throttle release,blows white smoke,which then clears up.slow release of throttle,results in no smoke.

White smoke unless it smell sweet is a normal byproduct of cold start engine, some can blow white smoke for quite a while

Runcible_Spoon wrote:#3 . the worst thing...when in gear,and brakes applied,any throttle to load it will cause it to run rough,detonate,and die. its undrivable right now.

this is a good challenge, the manifold vacuum is good, so you are close to sea level, jumping 1 tooth or 2 is not going to make it undrivable -I had 2 wiped out cam lobe and it was fine, except for the vibrations, and vacuum was decent- it can be too rich or too lean if undrivable, pull spark plug to check color, at least one on ea side #1 on the driver side and #2 on the passenger side, the most ahead one are fed by different side of the 2 barrel carb... 2,3,5,8 for the carb passenger side intake and 1,4,6,7 for the driver side intake.

Also an overactive EGR valve can throw things off, but rough, detonation and stalling...

Next would be a compression check, remember to keep the throttle plate all the way open with either a large screwdriver or any wrench of your choice

of course for a diesel guy, 1 8 4 3 6 5 7 2 for the ignition order... even the regular guys can f___k it sometimes

checked wire order...that was the first thing I did.
today I checked if the chain had jumped...used the " mark the balancer method" .it has about 10 degrees worth of slop in it...about what you'd expect,for a used engine.not the best,but not terrible.

pulled all the plugs...all carbon fouled,or what looks like baked oil fouling.i attribute this to the carb dumping fuel for so long.the plugs were some ngk-v4 plugs with that split electrode...replaced them all with new champion 405 plugs.

and I need new plug wires...3 came apart when I pulled them off the old plugs.all basic maintainance items,but none of it explains the timing issues,or the weird smoke problems...i'll get a new dizzy Monday,and find factory style wires for now...

also going to drain the oil,in case its become fuel contaminated...it does smell weird.

come to think of it,i should get some new valve cover gaskets...pull the covers and see if the rockers do theyr're thing and I don't have a cam lobe gone...i'll try and see if the cam is acting the way it should vs the timing marks with the covers off.

so...new dizzy arrived.now I need to find a proper size pin punch for the gears' roll pin.plug wires ordered,valve cover gaskets ordered.

and a question...that puff of smoke when I abruptly close the throttle.that means a hi vacuum condition...what are the odds of a stem seal popping off or a manifold gasket leak,and allowing oil to get sucked into the air stream during this condition of hi vacuum? seems to me the only way that this can happen,unless something is more seriously wrong with the carb,than I thought...if everything checks out reasonably well,i could be fighting a massive hidden vac leak...

Compression test done...

1...150 2...155 3...150 4...155 5...148 6...150 7...155 8...155 all were done cold and dry.compression dosn't appear to be an issue.took the valve covers off,and all the valves appear to be doing what they need to do,and the umbrella seals appear to be intact,though likely dry...assembly this afternoon.

Starts easier,and runs much smoother...a small victory but I'll take it.
Also found 2 vac leaks...only discovered when i got it running and started spraying brake cleaner all over the intake manifold and under the carb.

They are 2 holes on a small plate to the passenger side of the carb...looks like something from the PO's egr delete.

Replacing the coil next...wondering if its worth it to replace the original AMC tagged ignition box as well?

Runcible_Spoon wrote:Starts easier,and runs much smoother...a small victory but I'll take it.
Also found 2 vac leaks...only discovered when i got it running and started spraying brake cleaner all over the intake manifold and under the carb.

They are 2 holes on a small plate to the passenger side of the carb...looks like something from the PO's egr delete.

Replacing the coil next...wondering if its worth it to replace the original AMC tagged ignition box as well?

Great, send a pict of the 2 holes on the passenger side of the intake. I still have the AMC ignition box on the 85 with 216K miles and it has cooked a few times due to borderline overheating when the fan clutch gave up.

Also Make sure that your second flapper on the air cleaner housing is opening up, not the thermstatic flapper that direct warm air from the exhaust manifold but the secondary, closer to the filter element... I have a pict somewhere... to put posted soon



if it is missing or non-functional the engine will run like crappo

cant post ...pics too large,apparently.

anyway...I'm not certain if this little plate on the manifold is the culprit.the brake clean I was spraying was also right next to the carb base...so I could also have a leak at the spacer. the egr valve was left in place by the PO, and it could be stuck open. bad news is, i don't have the original air cleaner...the PO put a "performance" assembly on the carb.one of those crome things.i have a few snorkel types I can modify a bit.

it also backfired in my face...fun.

I still have excessive smoke, and the puff it gives out when the throttle is abruptly shut....more work yet.i'm going to try a cold start in the morning, on my way to NAPA.it's due to snow tomorrow, and temps to -5*c. we'll see how it behaves then...if I can get it going, i'll try more leak tracing and see if I can narrow it down.

Very sure that plate with 2 holes in it is for the choke.. Used to have steel tubes that lead to choke.

Yes, search for "choke stove" and you may find something about it. The holes connect together and cannot leak into the intake, so no opportunity for a vacuum leak there. The pocket the plate covers connects with the exhaust system, not the intake. There is a passage in the intake manifold that passes exhaust gas from one exhaust manifold to the other when the engine is cold. This both warms the intake manifold (to keep gasoline from condensing on the interior of the cold manifold) and provides heat for th make hot air in the choke stove. The choke stove conencts to the air horn as a supply of clean air, and then to the choke asembly where there is an orifice that applies engine vacuum to the coke cover, sucking in the heated air.

This is all covered in the TSM. Read the section about "choke circuit."

thanks!...that explains that then.
the leak must be around the carb base on that side...havn't pulled the egr valve off,so that's one more spot to look.

on a positive note,it started this morning at a temp of -1*c...took a few tries and some pedal pumping,but it fired and idled fairly well...just smoky.hard to figure where this smoke is coming from.puffs of blueish white.looks like excess fuel.i'm not losing oil,or coolant.

picked up a new coil ,rotor and cap.(found some corrosion in the original cap).not going to work on it till I find out what happened to my dodge. massive computer fit this morning,had me on the shoulder and then the CAA tow hook...bleh. also cold and miserable out.

Excess fuel typically gives black smoke. Oil burning is blue-gray. Water is white. Check the plugs.



This check should be after you've driven around some. There are dozens of articles online about reading the plugs.

Runcible_Spoon wrote:cant post ...pics too large,apparently.

anyway...I'm not certain if this little plate on the manifold is the culprit.the brake clean I was spraying was also right next to the carb base...so I could also have a leak at the spacer. the egr valve was left in place by the PO, and it could be stuck open. bad news is, i don't have the original air cleaner...the PO put a "performance" assembly on the carb.one of those crome things.i have a few snorkel types I can modify a bit.

it also backfired in my face...fun.

I still have excessive smoke, and the puff it gives out when the throttle is abruptly shut....more work yet.i'm going to try a cold start in the morning, on my way to NAPA.it's due to snow tomorrow, and temps to -5*c. we'll see how it behaves then...if I can get it going, i'll try more leak tracing and see if I can narrow it down.

good pick from Bcrawler



thinking about the excess oil, may a non connected or plugged PCV valve system



check that original post for more images

viewtopic.php?t=10648

as for pict posting you need to use a hosting site, google, I forgot what the others are using, photocroket requires a fee...