I was surprised at how much carbon was on these. They were new when we started. This was taken a couple weeks ago maybe a month ago.

Edited April 24Apr 24 by Wrongway

Ok, so 16 oz water bottle poured down the carb and engine still run's. I let the car run for about 5 mins after I finished with the water. Here's the video. My timer said she continued to run for 52 seconds after killing the power and hitting the kill switch. I started her up right after she finally stopped and shut her off again. This time I had my son pull the positive battery cable off while she was dieseling and it did no good. Positive disconnected and she kept running. Also, due to the excessive vibration in the video it put a small bend in the fuel fine just behind the elbow coming off the carb right where the collar is for the compression fitting causing a leak. I didn't have any extra fuel line in house so in the next video you'll see a black rubber line. But you get the point of how violent she gets when she shakes.

Edited April 24Apr 24 by Wrongway

Take her for a good run mate

See if that doesn’t clean up those combustion chambers 👍

4 hours ago, 64 kiwi boni said:

Take her for a good run mate

See if that doesn’t clean up those combustion chambers 👍

I can try it bro. It may be a couple of days before I'm able to, rain started tonight but I'll let you know what happens.

Disconnecting the battery positive wire only killed off the battery supply. It did not kill off the spinning alternator as a source of power during the dieseling episode.

It might not be hot carbon chunks that are your ignition source. It could be problems with the ignition key wiring.

Rick

18 hours ago, B52bombardier1 said:

Disconnecting the battery positive wire only killed off the battery supply. It did not kill off the spinning alternator as a source of power during the dieseling episode.

It might not be hot carbon chunks that are your ignition source. It could be problems with the ignition key wiring.

Rick

Ricks onto it !! that is dead right wrongway !!!

try removing the live wire to to the ignition coil ! see if that kills her instanly !

As i remember you wired your ignition through the heater controls as a theft deterant ?

19 hours ago, B52bombardier1 said:

Disconnecting the battery positive wire only killed off the battery supply. It did not kill off the spinning alternator as a source of power during the dieseling episode.

Yeah Rick I wasn't sure, but it was suggested so I tried it. I also tried disconnecting the alternator wire while dieseling. The same guy said it could be back feeding electricity. That didn't help either.

58 minutes ago, 64 kiwi boni said:

As i remember you wired your ignition through the heater controls as a theft deterant ?

Good memory Kiwi, yes, I did. So, pulling the positive wire from the HEI should kill it? I think that was the "theory" behind disconnecting the alternator. I'll try that tomorrow guys, thanks.

Yeah mate

If isolating the feed to your spark at the coil works like Rick suggested

You can then back track as to why it’s still getting power after you switch off the key

Sorry to hear your still having probs bro. Shouldn't be this hard. Good luck for a change.

Sorry for the late reply but I've been in the woods the last couple days. OK, remember I'm running an HEI dist. I did get back to playing with her today, warmed her up and shut her off to make sure she was going to diesel. She did, started back up and had my son shut her off so I could remove the back plug (C+ ground B+) wires. She continued to diesel. I than started her up and he shut her off so I could remove the front plug (Tech and Batt). She still dieseled. My son wanted to try (and I try not to discourage) removing both positive and negative battery after it started to diesel. That did nothing. So, I still have no idea, justa recap. Everything in fuel system is new and set at 6 PSI. Carb is new and now also has new needles, seats and floats. New wiring and no power at dist. when shut off. Engine has less than 50 miles since complete rebuild and "stream cleaned" the inside last week. Plugs were new than fouled out and cleaned too new again. Also, this is ONLY happening when she gets hot and the hotter she gets the more violent she is, to the point that she bent an aluminum fuel line.

So, is it possible that this could be a timing issue again. Remember we had a bunch, maybe had to advance it to run off of the shitty gas and now that everything is new, she is out by a couple of degrees? No sure it works that way so thought I'd ask.

If not any other ideas? I'm with Justa, this should not be this damn hard!

Wrong way

Ignition can certainly cause dieseling. So keep checking it.

Carbon build up on the pistons can do it, but the engine is fresh so that ain’t it.

The only other things that I can think be the problem is a wrong air/fuel ratio or the wrong heat range of spark plugs. I would check the spark plugs and carb after the ignition.

1 hour ago, Wrongway said:

Sorry for the late reply but I've been in the woods the last couple days. OK, remember I'm running an HEI dist. I did get back to playing with her today, warmed her up and shut her off to make sure she was going to diesel. She did, started back up and had my son shut her off so I could remove the back plug (C+ ground B+) wires. She continued to diesel. I than started her up and he shut her off so I could remove the front plug (Tech and Batt). She still dieseled. My son wanted to try (and I try not to discourage) removing both positive and negative battery after it started to diesel. That did nothing. So, I still have no idea, justa recap. Everything in fuel system is new and set at 6 PSI. Carb is new and now also has new needles, seats and floats. New wiring and no power at dist. when shut off. Engine has less than 50 miles since complete rebuild and "stream cleaned" the inside last week. Plugs were new than fouled out and cleaned too new again. Also, this is ONLY happening when she gets hot and the hotter she gets the more violent she is, to the point that she bent an aluminum fuel line.

So, is it possible that this could be a timing issue again. Remember we had a bunch, maybe had to advance it to run off of the shitty gas and now that everything is new, she is out by a couple of degrees? No sure it works that way so thought I'd ask.

If not any other ideas? I'm with Justa, this should not be this damn hard!

Wrongway, sorry I’m way behind on this. My time gets pretty limited for quite a while now so I don’t stay up on all that I would like. Frosty’s right! New engine build, highly doubtful for carbon. So timing could be to blame. Please explain the fuel setup. What do you mean 6 psi? Is that at the inlet of the carb? If so that’s too much! Try 4 psi, but no more than 5. Too much fuel pressure & too much advance timing can cause dieseling.

Also I read what Kiwi said about your antitheft setup. If you want I can give you a better setup that is something nobody finds & tuff to bypass, since they don’t know it’s there.

Edited April 29Apr 29 by Last Indian

So everything is brand new, fuel pump is Edelbrock p/# 1971, carb is Edelbrock AVS 2 800cfm p/# 1913, iv replaced the needles and seats then the floats per Edelbrock tech, new PSI gauge from Marshal Instruments. So, per Edelbrock tech, the fuel pressure at the carb should be 6psi, not to exceed 6.5psi at the carburetor. So, pressure was adjusted at the pump. The gauge is mounted to the firewall just ahead of the carburetor. The aluminum fuel line that got bent due to dieseling is the line coming off the firewall to the elbow on the carburetor. The last video I posted shows the engine dieseling for 52 seconds after being shut off. And again, it only does this if the engine is warmed up.

5 hours ago, Frosty said:

The only other things that I can think be the problem is a wrong air/fuel ratio or the wrong heat range of spark plugs.

When I put the carb back together, I turned air/fuel ratio screws all the way in and backed out 1 1/2 turns. The plugs were what NGK website recommended. Not saying ANY of this is correct, its justa the only info I had available.

Your spark plugs were filthy. They should be a nice tan or light grey colour when the mixture is right. Less than 50 miles after rebuild? The look of the plugs suggests lotsa carbon to me - when that stuff gets hot your engine will run on. Any chance of getting a camera (one a mechanic uses) down thru the plug hole?

You can check if your ignition wiring is wrong by removing a plug and leaning it connected onto the engine so it grounds. Fire it up and then switch it off whilst an observer watches that exposed plug. If it's still sparking whilst engine is running on, your wiring needs repair. If not, you got internal hot spots.

VW Beetles used an electronic pilot jet shutoff to prevent this sort of thing. My Husky mower has the same feature.

My two cents feels it’s carbon build up too like fitzy said

Reading those plugs , you have a carbon build up .

Take her for a drive mate now that you know your carb is behaving again and get it hot .

JustA check your timing too , what have you got it set at ?

I can’t recall ! Are you using closed chamber or open chamber heads ?

Edited April 29Apr 29 by 64 kiwi boni

10 hours ago, Wrongway said:

When I put the carb back together, I turned air/fuel ratio screws all the way in and backed out 1 1/2 turns. The plugs were what NGK website recommended. Not saying ANY of this is correct, its justa the only info I had available.

Ok, a little engine dieseling 101. Dieseling pretty much only happens in carbureted engines. This happens for a couple reasons. First & absolutely first is a fuel supply! No fuel no fire! Second is spark! Be it electric or a hot ember somewhere. Third is obviously air, but that only enables the dieseling to occur by completing the triangle.

The color of your spark plugs doesn’t concern me. I don’t know what fuel they run in NZ or Australia, but in the US we only have unleaded today. So all you’re going to have on the plug is black carbon or a medium gray color & the medium gray is rare in most carbureted cars today. You only get a tan or brown color with leaded fuel.

I suspect your issues is the carb & possibly some timing, but mostly carb. I would do this to verify that to be the case. You say it occurs when the engine gets hot! That is typical of fuel leakage of a carb. So whether you install a shutoff on the inlet line or choose some other way, get the engine hot. Cutoff the fuel supply to the carb & let it run out of fuel. If it stops smooth its a good indicator of carb issues. The other choice is put a different carb on which would actually be my first recommendation, but that’s expensive unless you have one lying around.

Carbs, unless you are very proficient at them are not easy to access. Too many things to be bad & cause fuel leakage. Worn throttle bushing, worn power jets, bad or incorrect gaskets, etc..

Edited April 29Apr 29 by Last Indian

See, and it still feels like fuel to me. I did consider carbon and ran 17oz of water through the engine last week. I don't think there would be that much carbon built up to cause all of this. I don't have an extra carb floating around but I will see if I have a valve, I can put inline. If not, I will get one ordered today.

9 minutes ago, Wrongway said:

See, and it still feels like fuel to me. I did consider carbon and ran 17oz of water through the engine last week. I don't think there would be that much carbon built up to cause all of this. I don't have an extra carb floating around but I will see if I have a valve, I can put inline. If not, I will get one ordered today.

Ok, before you jump through those hoops try this as it may answer the question quicker. Your carb is a 4 barrel right? If so adjust both front & rear throttle plates so they are completely closed when no throttle is applied. Next find some shim stock you can place between the screw & the stop to bring it back to where it’s in idle. Do what you need to do to get the engine hot. Then when you shutoff the engine remove the shim stock & hold the throttle levers securely closed. That may well be enough to stop any siphoning action. If that proves successful, you have your answer.

Edited April 29Apr 29 by Last Indian

Ok, so not sure if this is the same thing or not, but the last time I shut her off and she started dieseling I used a shop rag and put it over the carb to suffocate it. It worked and she stopped instantly.

Sorry I didn't think about including that earlier. I did it as an afterthought. I was fed up and ready to go inside for the night and never even thought about doing that until now.

Edited April 29Apr 29 by Wrongway

9 minutes ago, Wrongway said:

Ok, so not sure if this is the same thing or not, but the last time I shut her off and she started dieseling I used a shop rag and put it over the carb to suffocate it. It worked and she stopped instantly.

Sorry I didn't think about including that earlier. I did it as an afterthought. I was fed up and ready to go inside for the night and never even thought about doing that until now.

It’s similar, but not quite the same. You need air, aka oxygen, to complete the triangle as well as siphon the fuel, Venturi effect. Yet that doesn’t prove the carb to be the issue. What you want is to eliminate the ability to siphon or drain fuel into the manifold if the carb is not functioning right. Making sure the throttle plates are completely closed does that while not choking the engine for air, per se, even though closing the plates does stop the air as well.

When you rebuilt the carb did you set the throttle plate adjustment both front & back?

I did not adjust the throttle plates. Being it was a brand-new carb all I did was replace all the gaskets and repaired a float that had a hole in it, then the needle and seats and gaskets, then replaced the floats and gaskets the last too per Edelbrock tech. The only adjustments I made were to the air/fuel ratio screws per Edelbrock tech which were to bottom them out and back off 1 1/2 turns and the float adjustment at 7\16 and 15/16 on float drop.

Alright. When you adjusted the throttle plates, were they closed as much as possible, but not to the point where they actually rested on the bores of the carb body? Likewise how strong is your return spring? That can also make a difference! Try the throttle plate suggestion I advised & even before that, get the car hot. Before you turn it off take the air cleaner off if it’s on Than have your son turn the car off. As he does that put your finger over the carb air vent tube & make sure it seals the tube tight. If the siphoning if somewhat mild that may be enough to stop the fuel from leaking. Worth a shot to answer a question.

Edited April 29Apr 29 by Last Indian

Ok, so if I did what you asked correctly, then it was a success. If I didn't then at least what I did was successful. So I backed out the idle screw to where it wasn't touching the throttle after taking a measurement to make sure the shim was big enough to still idle. Then justa using a piece of paper folded to size stuck that in between the idle screw and throttle lever. Had my son turn her off and I removed the shim and pushed the throttle linkage to make sure she closed. She stopped immediately. As I tell my son, once doesn't make a pattern so I repeated that test 3 times with the same results. Here are the videos. So your thoughts?

1 hour ago, Wrongway said:

Ok, so if I did what you asked correctly, then it was a success. If I didn't then at least what I did was successful. So I backed out the idle screw to where it wasn't touching the throttle after taking a measurement to make sure the shim was big enough to still idle. Then justa using a piece of paper folded to size stuck that in between the idle screw and throttle lever. Had my son turn her off and I removed the shim and pushed the throttle linkage to make sure she closed. She stopped immediately. As I tell my son, once doesn't make a pattern so I repeated that test 3 times with the same results. Here are the videos. So your thoughts?

I would feel encouraged that fuel is the issue. Why? Because of the way a carburetor works. As long as there is air flowing through the Venturi’s then fuel flows into the manifold. It per se sits there until a cylinder sucks it in. So turning off the engine, if it were hot carbon it would still want to pull that fuel in & then fire.

So try this. Do the same thing again, but this time leave the engine run. Pull out the shim & see if the engine dies or try’s to keep running. If it keeps running, don’t turn it off, but push on the throttle lever to put a little more pressure on it to close the plates & see if it dies.

If that proves out, I.E. keeps running till you push on the lever. Than try it again & close off the air vent as I had described.

There may still be some timing issues, but one thing at a time.