2150 and Fuel/air mix not right. Cant get jetting right

[MadMax_636]

NOTE: I asked this same thing on Reddit and couldnt get much help besides try cleaning and clearing out the carb.

So, My 84 has the duraspark. Ive got the timing set at 10 BTDC and thats good.

I cant seem to get the passenger side spark plugs to look as good or look to run as rich as the driver side. Ive been playing around with timing, jets, and power valves and I think Ive got the power valve right and Ive got the timing set to 10 degrees and the spark plug gap at what it calls for.

At 10 degrees the idle mix screws are happy sorta lean. When I drive it feels fine-ish but when I pop the spark plugs out they aren't brown ish. They are either a little peppered or clean/white.

I was running 64 sized jets and these results Im describing is/was this those. Plus, When I tried to start my truck leaving work. It needed a bit of gas (Throttle) to get her started. I dont have the choke system hooked up since the wiring is gone/needs to be redone. I just use my foot to feather it when warming up.

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UPDATE: I just rebuilt the carb. I cleaned out the whole carb and let it soak in carb cleaner and rinsed with water and then blew it out with compressed air.

Took a little bit to get her idling but I got her idling and the idle mix set. When I went to drive her I couldn't feel any of the bucking or anything of that sort like before but on my day home after the test drive. She died/stalled on me. She started up and I got home fine. Could that be due to the idle speed improperly set? If so, I brought the idle speed up. I also checked the spark plugs and they didn't seem to look any different. Still looked dry, (passenger side) peppered a bit, and looked clean/lean but not OVERLY lean. I didn't hear anything that could suggest pre-ignition/detonation.

The driver side looked better than the passenger side. The passenger side looked peppered and have a yellowish tint to it. Should I take the plugs back and get them replaced and regap them to something else?

Could the spark plug gap effect the AFR and be causing the spark plugs to look/run as they are?

Im considering just getting a rebuilt motor and dropping it in and slapping a 4 barrel intake on it. Id rebuild the motor I have but there are ZERO machine shops that can get it done when I needed/as soon as I could get a new motor shipped to me.

 

[rusty ol ranger]

Im wondering if you have one bank of cylinders weaker then the other. Run a compression check. Possibly even a blown intake gasket allowing excess air in leaning out the mix.

Carbs are completly reliant on engine vacuum to get the mix to the cylinders.

Spark plug gap i dont think would create that drastic of difference.

The stalling at idle very well could of been the idle set to low. I wouldnt worry untill you get the rest figured out.

Its not uncommon on carbed engines to get uneven mix, but its usually the cylinders closest to directly below the carb, on both sides, that read rich.

 

[MadMax_636]

Im wondering if you have one bank of cylinders weaker then the other. Run a compression check.

Carbs are completly reliant on engine vacuum to get the mix to the cylinders.

Spark plug gap i dont think would create that drastic of difference.

The stalling at idle very well could of been the idle set to low. I wouldnt worry until you get the rest figured out.

Its not uncommon on carbed engines to get uneven mix, but its usually the cylinders closest to directly below the carb, on both sides, that read rich.

Ill run a compression test once I get one.... I know, I should already have one.
The weird thing is that the cylinder that im checking is the middle plug on the passenger side. Since the #1 spark plug is hard to get to and Ive crack multiple plugs trying to get it out.

 

[rusty ol ranger]

Ill run a compression test once I get one.... I know, I should already have one.
The weird thing is that the cylinder that im checking is the middle plug on the passenger side. Since the #1 spark plug is hard to get to and Ive crack multiple plugs trying to get it out.

You need to read all 3 before you blame the whole bank. That middle one *should* be the richest of the 3. But if your other 2 on that side look good then you got a spot to really look. Either worn rings on that cylinder, or blown intake gasket.

 

[MadMax_636]

You need to read all 3 before you blame the whole bank. That middle one *should* be the richest of the 3. But if your other 2 on that side look good then you got a spot to really look. Either worn rings on that cylinder, or blown intake gasket.

This is what the spark plugs looked like before I changed them recently.

The photo on the left are the plugs are in the order of which bank they came out of. The photo on the right is that middle plug on the passenger side.

NOTE: I fed her some seafoam by spraying it down the carb to see if I could clear anything up. The color of them in the photo on the left is the end result of that. Also, I didnt properly gap them until now. I left them at whatever they were when they came out of the box. The plugs in her new are around .044-.046 so if that makes a difference.

Ill get a photo of the current plugs tomorrow. There is sometimes hard starting as if shes flooded or something. Im thinking it might be spark related since She will just crank and sometime fire off and others just a slight turn of the key she will fire off. Its weird.

Like I said, Im planning on replacing the worn out motor soon. Im thinkin shes got around 290K + miles on her since the odo reads 95K and still goes up. Its not broken.

 

[franklin2]

If you leave the carb completely stock as it was when it was on the computer system, it will run fine, it's what I have been running for the past year and it runs great, I did have to modify the choke system a little bit though.

It's my impression from listening to people in the know, when trying to read the sparkplugs, you need to know what you are doing. What I have heard is if you want to read the plugs to set the main jets, you need to start with a clean set of plugs, run the engine hard down the road and then kill it with the keyswitch. Then pull the plugs and read them. If you let it idle, it ruins the reading, your idle circuit could be doing anything and will ruin the main jet reading on the plugs. Yes, this means checking them on the side of the road, or getting a tow back home to pull them in the driveway.

If it runs good, I would put the plugs back in and drive it.

 

[MadMax_636]

If you leave the carb completely stock as it was when it was on the computer system, it will run fine, it's what I have been running for the past year and it runs great, I did have to modify the choke system a little bit though.

It's my impression from listening to people in the know, when trying to read the sparkplugs, you need to know what you are doing. What I have heard is if you want to read the plugs to set the main jets, you need to start with a clean set of plugs, run the engine hard down the road and then kill it with the keyswitch. Then pull the plugs and read them. If you let it idle, it ruins the reading, your idle circuit could be doing anything and will ruin the main jet reading on the plugs.

If it runs good, I would put the plugs back in and drive it.

Thanks Frank. Tomorrow, Ill get some new plugs and gap them. Then run it hard down the road and kill it it and check it. Like you said.

 

[franklin2]

I added something in my post you might not have seen. This means pulling the plugs to check them on the side of the road, or getting a tow back home to check them there. You can't run it at all after you kill it and throw it in neutral and come to a stop with the engine off. Any idling will ruin the readings.

 

[MadMax_636]

I added something in my post you might not have seen. This means pulling the plugs to check them on the side of the road, or getting a tow back home to check them there. You can't run it at all after you kill it and throw it in neutral and come to a stop with the engine off. Any idling will ruin the readings.

I live on a long road. Plenty of places to pop it into nurture after killing it and coast onto somewhere to read them.

 

[rusty ol ranger]

That is really strange

 

[MadMax_636]

This is after running hard down the street and shutting off and pulling into a safe place. This is with cruising and hard driving (power valve) 10 degrees of timing.

 

[19Walt93]

Are you losing coolant? As shiny white as those plugs are I'd suspect it's burning coolant. Is there milky foam on the underside of the oil filler cap? Coolant in the oil causes a milkshake that can get sucked into the PCV.

 

[MadMax_636]

Are you losing coolant? As shiny white as those plugs are I'd suspect it's burning coolant. Is there milky foam on the underside of the oil filler cap? Coolant in the oil causes a milkshake that can get sucked into the PCV.

Nope, The coolant is good and my PCV system is capped off and I just put a breather in it. Since Id rather not have the blowby crap being put back into my motor.

Temp never goes above 195. Never even gets close to 200 on the gauge (I have an aftermarket gauge since the dummy light doesnt work anymore.)

 

[19Walt93]

I'd hook the PCV back up and make sure it has a good supply of filtered air entering the other valve cover. It's better to burn off the fumes than let combustion blow by condense into the oil.

 

[MadMax_636]

I'd hook the PCV back up and make sure it has a good supply of filtered air entering the other valve cover. It's better to burn off the fumes than let combustion blow by condense into the oil.

ok, Ive just heard about putting air cleaner/filters into the PVC port works fine. Thats mainly why I did it.

This is what Ive got in my PCV port on the valve cover https://www.oreillyauto.com/detail/...ce-white-oil-breather-cap/42869/4740551?pos=5