CJ8 carbon deposits?

snipped-for-privacy@yahoo.com did pass the time by typing:

Yep.. too rich. (a little black is ok, flakes of black indicate way rich conditions or plugs that are too cool)

safely is a matter of conjecture and depends on the amount of carbon that has built up.

Some old tricks involve slowly dribbling water down the carb. That breaks up the carbon. Some use ATF fluid as well and that will produce a HUGE black cloud.

Others have mentioned SeaFoam, but I though that was only for cleaning the oil galleys.

I worked in garages for years and they always used a pint of ATF to decarbon an engine.

I did it to my CJ before a head gasket job and it looked like new with a couple big loose chunks of carbon still in a couple cylinders.

You heat up the engine and slowly pour the pint of ATF down the carb while keeping your hand on the throttle to keep it running. Pour too fast and it will stall out, you don't want that.

Then when it's finished shut it down for 10 minutes or so. Start it back up and rev it good and you are good to go.

It makes one massive cloud of smoke, but does a sweet job.

I have been told that a pint of water will do the same, but have no first hand experience on that.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

snipped-for-privacy@yahoo.com wrote:

No Kiddin' Right Mike!? I'm kinda dealing with the same thing. So what you're saying is to drizzle a pint of ATF straight down the throat of the carb. Obviously, not trying to stall the engine. Once the last drop is in, shut it down 10 min's. Fire it up and give it a rev. Sounds pretty cool. I'd love to try it just to get my neighbor reaction! They used to shake their heads at my old nissan that burned a quart of oil every tanks of gas.

Paul, ATF will work but it'll create a dense white cloud of smoke that your neighbors will hate you for, or call the cops or fire department on.

More commonly used for that purpose is plain old water. It works great and it doesn't produce huge clouds of smoke. Do it the same way as Mike described for ATF, it's what every mechanic I've ever seen do this uses and recommends. I've done this several times and it's a highly effective way to get rid of carbon deposits. Make darned sure to maintain control of the water and feed it in very slowly, you don't want to accidentally dump the entire container into the intake and cause hydrolock. I feed in 12-14 oz. of water and spend at least a minute to two minutes doing it.

Jerry

Old timer in our tire shop used Marvel Mystery Oil... __ Steve .

When I say 'one massive' cloud of smoke, I am not exaggerating. LOL!

Mike

Paul Brogren wrote:

If you have a hand throttle, that will help. Or you can shove something into the linkage to keep your throttle open a little. The water will bog your engine down a little and a little extra throttle helps keep it running.

I'm gonna try the water spray tonight. I didn't realize that the amount of ATF smoke could be as bad as you say. Good thing I didn't try it. My condo neighbors would be quite upset for sure. Thanks Always, Paul

Any cat implications with ATF ? (other than the choking feline variety).

Dave Milne, Scotland '99 TJ 4.0 Sahara

: > I'm gonna try the water spray tonight. I didn't realize that the amount of : > ATF smoke could be as bad as you say. Good thing I didn't try it. My condo : > neighbors would be quite upset for sure. : > Thanks Always, : > Paul : >

: > > On Thu, 2 Oct 2003 01:26:05 UTC Mike Romain : > > wrote: : > >

: > > > I worked in garages for years and they always used a pint of ATF to : > > > decarbon an engine. : > > >

: > > > I did it to my CJ before a head gasket job and it looked like new with a : > > > couple big loose chunks of carbon still in a couple cylinders. : > > >

: > > > You heat up the engine and slowly pour the pint of ATF down the carb : > > > while keeping your hand on the throttle to keep it running. Pour too : > > > fast and it will stall out, you don't want that. : > > >

: > > > Then when it's finished shut it down for 10 minutes or so. Start it : > > > back up and rev it good and you are good to go. : > > >

: > > > It makes one massive cloud of smoke, but does a sweet job. : > > >

: > > > I have been told that a pint of water will do the same, but have no : > > > first hand experience on that. : > > >

: > > > Mike : > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 : > > > 88 Cherokee 235 BFG AT's : > > >

: > > > snipped-for-privacy@yahoo.com wrote: : > > > >

: > > > > I'm getting my CJ8 six cylinder in shape. : > > > >

: > > > > I recently replaced the spark plugs. Though old in age they have very : > > > > few miles on them; they looked very good -- except for a lot of : > > > > carbon-looking darkness away from the gap. : > > > >

: > > > > I also shined a bright light into the cylinders where it appears VERY : > > > > dark and carbon-like on the top of the pistons; like a deposit. : > > > >

: > > > > This is probably due to the couple of hundred miles/year I've put on : > > > > the Scrambler for the past few years; along with the old, never quite : > > > > right stock carburator (now replaced with a Weber). : > > > >

: > > > > Engine seems in great shape and repeated oil analysis confirm that : > > > > there is very little wear over the 51,000 miles. : > > > >

: > > > > Question is -- is there some way without dismantling the engine to get : > > > > rid of these deposits? Is there something I can put in the gas that : > > > > will remove them safely?? : > > > >

: > > > > I've been told this is a common issue in the marine industry, but : > > > > don't know what to use. If there is anything that will work?? : > > > >

: > > > > Any suggestions, please ..... : > > > >

: > > > > Thanks. : > > > >

: > > > > Mike : > > > > Michael Pomeroy : > >

: > >

: > > -- : > > Will Honea

Dave Milne did pass the time by typing:

Possibly. Water would be a better choice if you have a cat even if it is the feline variety. :)

Not that I have ever seen.

The garages use it as a part of a tune up for 'city' driven vehicles to stop pinging and I never saw one come back with any troubles.

Mike

Dave Milne wrote:

good to know, thank you both.

In appropriate amounts water works wonders on carbon build up. If you've ever torn down an engine that's had an internal coolant leak into the combustion chambers (bad head gasket, head crack, etc.) the only piece of good news is the lack of carbon. Combustion chambers are nearly clean as new.

Another tactic to get carbon off the intake valves of newer engines with FI, EGR and retarded ignition timing has been to blow crushed walnut shells through the intake ports (with the valves closed, of course). Audi and BMW were using this as a fix back in the 80's and apparently it's still a recognized cure. I'm not sure if you are required to eat all the walnuts first as part of the procedure and suggested repair time.

you would have thought cats would give you loads of respect for being able to Hunt Really Big Things, but nah !

I have no idea why I just said that.

Dave Milne, Scotland '99 TJ 4.0 Sahara

: > Possibly. Water would be a better choice if you have a cat : > even if it is the feline variety. :)

When I was in the Air Force back in the 70's they used to do this to jet aircraft engines.

Nowadays, I go to the parts counter, get a can of GM's Top Engine Cleaner and use that. Pour it down the intake slowly until you get to almost the end of the can...then pour the last bit down fast enough to kill combustion and stop the engine...let it heat soak for 1/2 hour and then restart the vehicle and take it for a ride. Works real good on the valve stems as well as the tops of the pistons.

Smoke issue is somewhere between water and ATF :-)

-- Old Crow '82 Shovelhead FLT 92" 'Pearl' '95 Jeep YJ Rio Grande ASE Certified Master Auto Tech + L1 TOMKAT, BS#133, SENS, MAMBM

couldn't get through to your reference, but I'm assuming you are referring to that gay bloke whose white tiger nibbled his neck a bit hard ?

Dave Milne, Scotland '99 TJ 4.0 Sahara

: > you would have thought cats would give you loads of respect for being able : > to Hunt Really Big Things, but nah ! : >

: > I have no idea why I just said that. : >

: > Dave Milne, Scotland : > '99 TJ 4.0 Sahara