Pump Fuel Stink?

[XframeFX]

With a dump of snow overnight and into today, my cruising season has come to an end.

There’s an 8th tank of ethanol free 94 octane that will have to over-winter. This isn’t much since my fuel gauge is calibrated for fumes when the needle is at 0%. No Reserve!

I will soon add stabilizer. I also remove the fuel cap and cover with plastic wrap and fat elastic band along with plugging the vent hose next to it.

 

I will also get a break from demands to strip in the laundry room, shower and take my clothes to the backyard to burn! (Actually, launder them but a separate load with extra rinse!)

WHAT IS IT WITH TODAYS FUEL, THE STINK AND EXCESS WATER OUT THE TAILPIPES? AM I THE ONLY ONE?

At first, it may appear as unburned fuel but, no. Sparkplugs are tan.

My son relates saying whenever he installs a catalytic converter bypass pipe in his past and current cars, has the same stink in his clothes and hair. Ah, no. He’s too young to know what it was like. I have my Riviera for 43 + years, I do not recall fumes being an issue until now.

 

Again, who else has this issue? It appears to be modern fuel?

 

[RivNut]

How do you intend to compensate for the condensation that will form in the tank from changes in outside temperatures? The more fuel in the tank, the less air in the tank and therefore less condensation to be absorbed by the fuel in the tank.  Nothing you can do to seal the tank against condensation! 

[NTX5467]

1 hour ago, RivNut said:

How do you intend to compensate for the condensation that will form in the tank from changes in outside temperatures? The more fuel in the tank, the less air in the tank and therefore less condensation to be absorbed by the fuel in the tank.  Nothing you can do to seal the tank against condensation! 

No heated garage for your treasure?  Agree on the need for a full tank to decrease condensate forming.  The question I have is where was 94 pump octane E0 fuel found?

 

NTX5467

[XframeFX]

Too late to fill-up. Snowed all night and all day, The nasty arctic finger came through Alberta's back door and parked over the prairies!

So, my Riv is in the garage for the winter. I turn ON the furnace only while working in the garage. Too cold/expensive to set a constant temperature and all OH Door thresholds freeze with the temperature differential.

I usually throw a gerry can of fuel in the tank mid winter to freshen it up. Winter fuel is usually blended to help with condensation. Never a problem it the past.

Chevron 94 is the little bit of fuel in it now. But Shell and Petro-Canada fuel is supposed to be ethanol free as well.

 

Anyone have issue with Fumes?

[gungeey]

If the couple gallons in the tank is concerning you why not drop the tank and dump it into your daily driver? Its what I've done when a car is getting shut down 6-8 months. Not much more than an hours time as you know

 

 

 

 

 

 

 

PS: F it.

 

 

 

. Just drive it in the winter as roads allow 😆 We'll be dead before they rust out

[NTX5467]

Get an inline electric fuel pump, as used on some GM diesel pickups possibly, hook it to the fuel pump inlet hose, then drain it effortlessly from that direction or possibly also use a long rubber fuel line hose inserted into the filler neck?  Use approved gas cans for storage or transfer.  Then, when weather warms/drys, put fresh fuel in it (5 gallons at a time) and check the gauge calibration.

 

Enjoy!

NTX5467

[XframeFX]

Sorry I mentioned remaining fuel in my tank. Not concerned.

My question is:

FUMES WHILE DRIVING & IDLING (troubleshooting with hood up). Am I the only one? Again, I have to change clothes every time after driving my Riviera. Must be pump fuel, meant to burn in modern engines with catalytic converters! Burned fumed, unburned fumes, maybe a problem with my Nailhead?

[NTX5467]

Perhaps when you diagnose the reason that those two plugs look different, you'll also find the reason for the smell?  NOT related to "modern fuel", just inefficient burning of such.

 

NTX5467

[1965rivgs]

44 minutes ago, XframeFX said:

Sorry I mentioned remaining fuel in my tank. Not concerned.

My question is:

FUMES WHILE DRIVING & IDLING (troubleshooting with hood up). Am I the only one? Again, I have to change clothes every time after driving my Riviera. Must be pump fuel, meant to burn in modern engines with catalytic converters! Burned fumed, unburned fumes, maybe a problem with my Nailhead?

  Most likely raw fuel if the engine is not running well but can also be blow by escaping from the breather and making its way into the cab under certain throttle conditions. I've had dozens of '60's cars with vented breathers and even the slightest blow by, which would account for a significant number of those I've owned, especially Nailheads, leave an odor in my clothes...old car cologne!

  Once you get the car running well, add a closed breather routed back into the air cleaner to consume the blow by.

Tom

[EmTee]

I have read that a very lean condition can make stinky exhaust.  That might make sense given the color of the insulators on 6 of your spark plugs.  I'm still puzzling over why #1 & #7 are dark.  Bernie's comment coupled with the stinky exhaust might actually be plausible...

[1965rivgs]

44 minutes ago, EmTee said:

I have read that a very lean condition can make stinky exhaust.  That might make sense given the color of the insulators on 6 of your spark plugs.  I'm still puzzling over why #1 & #7 are dark.  Bernie's comment coupled with the stinky exhaust might actually be plausible...

  Lean misfire...it produces a rich exhaust.

Tom

[XframeFX]

I purchased fuel from the same place all summer. A little intimidating, 4-grades. 87/89/91 from one nozzle and 94 octane from a seperate dedicated nozzle like diesel.

I asked if the lone nozzle was indeed 94 and not diesel. Then I asked "Do you have diesel fuel?". Answer, "NO"

Other stations such as Shell and Petro-Canada have 87/89/91/94 all from the same pump nozzle with Diesel seperate of course.

 

Thanks All. No Nailheads close by to compare.

I now know a smooth idle for a Nailhead is the Norm.

It seems I'm the only one with nasty fumes. When troublshooting, I use dual long dryer vent pipe to carry exhaust away. At a car meet, I stay away from the back of my Riviera when running. No smoke, no leaks, no noise except some Lifter clatter on startup after sitting for a week. Its just that smell!

 

 

 

 

Edited October 25, 2023 by XframeFX (see edit history)

[XframeFX]

An article from 2013.

Much I already know but, good common sense relating to carbureted engines operating with modern fuels.

A Lean condition at idle? Aromatics? Premium fuel life already old being slow sellers at sleepy gas stations?

https://www.enginebuildermag.com/2013/11/impact-of-todays-fuels-n-carbureted-engines/

 

[EmTee]

@edinmass would probably suggest finding someone with a 5-gas analyzer. 

 

Can you tell. or do you know how the intake manifold runners are routed from the carburetor interface (i.e., the four venturi holes) to the intake runners on the heads?  Is there by chance a shared path for cylinders 1 & 7?  That lower right hole sure looks awfully black...

 

[RivNut]

This might help with your question. The left rear feeds #s 5 & 8

 

Edited October 26, 2023 by RivNut (see edit history)

[EmTee]

Hmmm, so it can't be that each 'hole' feeds only two cylinders, since the forward two holes are the primary venturis and the rear two are the secondaries.  I'm interpreting that figure to mean that the passenger side of the AFB feeds cylinders 1, 4, 6 & 7; while the driver's side of the AFB feeds cylinders 2, 3, 5 & 8.  Interestingly, that would suggest cylinders 1 & 7 are both fed from the same side of the carburetor.  Furthermore, it looks to me as though the intake runners for #1 and #7 are on the lower plane of the manifold.  What if the passenger side of the AFB is inadvertently dumping fuel...?  Where in the carburetor would one look for a cause for that problem?

[Bloo]

42 minutes ago, EmTee said:

I'm interpreting that figure to mean that the passenger side of the AFB feeds cylinders 1, 4, 6 & 7; while the driver's side of the AFB feeds cylinders 2, 3, 5 & 8.

A typical setup used in dual plane manifolds.

 

There's a little confusion about rich and lean here. Lean exhaust stinks worse than rich exhaust. It won't poison you like rich exhaust can, but it stinks far worse. Your eyes will burn. The main difference between rich and lean exhaust is the amount of Carbon Monoxide (CO). There is a lot of CO in rich exhaust and almost none in lean exhaust. Anything that causes a misfire will cause excess HC (unburned gas) in the exhaust. This could be a mixture problem, rich or lean, or a spark or mechanical problem.

 

As for the stink, any car with no catalytic converter will stink up the occupants clothes badly if exhaust is getting in the car. Even a perfectly tuned engine will do that. Look for rust hole in the trunk floor, or rear quarters, bad trunk gasket, lights mounted without gaskets, etc. The location where the exhaust pipe exits the rear of the car, and the way the tip is aimed can even matter. With the windows up and the vents closed, the cabin is under fairly low pressure. Meanwhile the exhaust is swirling around in the low pressure area made by the tail of the car is it moves through the air, and pelting the back of the car. The tumbling exhaust behind the car is just waiting to come in through any hole it can find. From the late 70s on, many car manufacturers had a little bit of outside vent open and ran the heater fan on low speed to pressurize the cabin, even when the heater and A/C are shut off. Not a perfect way to keep the exhaust out, but better than nothing I guess. No doubt this was done to prevent carbon monoxide poisoning.

 

As for water in the exhaust... that's normal. You might not always see it due to heat, but water (H2O) is one of the chemicals you get the most of when you burn gasoline. Carbon Dioxide (CO2) is another. If you could theoretically burn gasoline perfectly, all you would get is carbon dioxide, water, and whatever inert gases were in the air used to burn the fuel, mostly Nitrogen. That water is why your exhaust rusts out. It is also why V8 cars with dual exhaust and a heat riser rust out one side. One side tends to collect water and the other does not, due to the difference in heat. Some car owners have reported more visible water when using ethanol blended fuel. I'm not sure why that is, or if it's really true on more than a few cars. It might be. It is difficult to nail down because in the old days some cars dripped a lot more visible water out the tailpipe than others, with no obvious reason why. The water is present in all cases. It was always there.

 

 

[RivNut]

Now that I look at the illustration, it’s confusing. It’s like the primaries feed the front four and the secondaries feed the back four. Can’t be.

[XframeFX]

2 hours ago, Bloo said:

As for the stink, any car with no catalytic converter will stink up the occupants clothes badly if exhaust is getting in the car.

Well, no exhaust entering the car. I inserted a round foam pad inside the bottom of the steering mast jacket. (A common complaint). But, I do have a leak at the RHS Exhaust manifold to the Cyl. Head. You see, I removed gaskets based on Russ M's "Common Nailhead Mistakes". I could not smear the flanges with Hi temp copper dope. I'd like to think the leak dimenishes with heat. It does leak on startup.

As for water emiting out of the tailpipes when everything is HOT, it flows down my driveway. A lot of water! I drilled holes in each end of the muffler to avoid accumulation. Again, this is when hot.

 

As for Lean operation, I swapped same size metering rods from another 3503 AFB after cleaning of course. Didn't affect idle quality of course. That was with 1st set of sparkplugs I should examine those.

 

My Riviera is a real Looker but a turn-off with those fumes which are quite noticable. It makes my Riviera an old car.

[Bloo]

An exhaust leak under the hood could sure do it....

 

3 hours ago, RivNut said:

Now that I look at the illustration, it’s confusing. It’s like the primaries feed the front four and the secondaries feed the back four. Can’t be.

One primary and one secondary as a team feed four cylinders. On a dual plane manifold, that's usually the front and the rear cylinders on one side, and the two inner cylinders on the other side.

 

Edited October 26, 2023 by Bloo (see edit history)

[1965rivgs]

6 hours ago, XframeFX said:

Well, no exhaust entering the car. I inserted a round foam pad inside the bottom of the steering mast jacket. (A common complaint). But, I do have a leak at the RHS Exhaust manifold to the Cyl. Head. You see, I removed gaskets based on Russ M's "Common Nailhead Mistakes". I could not smear the flanges with Hi temp copper dope. I'd like to think the leak dimenishes with heat. It does leak on startup.

As for water emiting out of the tailpipes when everything is HOT, it flows down my driveway. A lot of water! I drilled holes in each end of the muffler to avoid accumulation. Again, this is when hot.

 

As for Lean operation, I swapped same size metering rods from another 3503 AFB after cleaning of course. Didn't affect idle quality of course. That was with 1st set of sparkplugs I should examine those.

 

My Riviera is a real Looker but a turn-off with those fumes which are quite noticable. It makes my Riviera an old car.

  If you have an exhaust leak or any blow by escaping the open breather under the hood the fumes will enter the cab.

Tom

[NTX5467]

What I learned about "lean misfire" one Saturday.  I had the Camaro at the deaelrship to try and get the emissions-spec Holley 4160 I had put on it (with the cam upgrade, 210 @ .050) a few months earlier.  I was wanting to get the idle mixture better as to speed and mixture.  With the engine fully warmed and hooked up to the exhaust analyzer, also measuring intake manifold vac, I firmly set the parking brake and proceeded to do the idle mixture adjustments in "P".  I had read what the desired CO levels should be, so that was my target.  Only thing is that when I started to get close to that level, the HC digital display started going crazy.  I could lean the mixture to get that lower level of CO, but the HC numbers were wildly varied, changing as quick as the display could change.  Not right.  So I slowly went richer until the HC numbers calmed down greatly, just drifting a bit rather than jumping all over the place.  THAT was "lean misfire".  I also need to state that for this testing, a Test Tube was installed.

 

Then, when I put it in gear, I noted that the intake manifold vac dropped to 10.5" Hg, steady.  I found that interesting as the two-stage power valve in the Holley started to open its first stage at 10" Hg.  So, with the engine loaded against the brake, a/c running, the least bit of throttle would drop the vac to the 10" Hg level, which only slightly-enriched the mixture.  Which is what it was designed to do, with full enrichment happening at the normal 5.5" Hg level.  All of this with the stock torque converter.  Knowing these things, observing them, I found interesting, but did not worry about them again.

 

During lean misfire, the engine just quiverred a slight bit more.  Nothing like a misfire caused by a fouled spark plug by any means.  If the meters had not been doing what they were, I would have never known what was going on, or why.

 

Using my shadetree method of adjusting hot base idle speed and carb mixture relies on how the exhaust smells, or minimized HC smell, out the tail pipe.  I'm defining "hydrocarbon smell" as a fuel mixture that is too rich, which can also be smelled on the engine dipstick and oil thereon.  As if the choke never gets fully open and/or black smoke is emitted from the tail pipe.  The smells coming from the crankcase road tube are more of an "oil smell", by observation.

 

I realize that your driving season up there has mostly come to an end, so this mystery should also exist next April.  When NEW fuel will be needed after the old fuel is driven-out.  In the mean time, put some new spark plugs in those two cylinders that are different from the others.  Re-tweak the idle speed and mixture, if needed.  Then drive the car on the Interstate and recheck the insulator colors.  Check those two plug wire's circuits for resistance/continuity, too.

 

The look of the manifold plenum is interesting, but might also be the result of the crossover passage being a bit "deposited-up" in that one area.  Interesting, but inconclusive as the carb barrels on that location are not all operating at normal driving speeds.  Presuming, of course, that the different look is under the secondaries.

 

So, put the winterized car away for the winter and enjoy the holidays!  Then when you get bored, go out and wax it, to ready it for its spring re-awakening!

 

Take care,

NTX5467

[EmTee]

Does anyone think that there might be a problem with the carburetor that is affecting the passenger side circuits?  I'm still thinking there must be a reason why the #1 and #7 plugs look darker than the others.

[1965rivgs]

11 hours ago, EmTee said:

Does anyone think that there might be a problem with the carburetor that is affecting the passenger side circuits?  I'm still thinking there must be a reason why the #1 and #7 plugs look darker than the others.

  There are two threads running which address John's issue. If you read the other you will see the answer to your question is yes, for various reasons.

Tom

[XframeFX]

Only solution for RH exhaust manifold to cyl. head leak I can think of is to use Hi Temp RTV. OK? Will not induce a crack as a gasket would? I'd have to remove the manifold in order to smear on sealant.

 

As for blowby, I'm on my 3rd PCV valve even thought the previous two were new and functional. I can't see how blowby would escape out the oil filler breather. However, I discovered a local 1963 Riviera with a mod for crankcase breather.

To do this mod, I'd require a 1964 - 66 valve cover with a hole at the front.

 

 

Edited October 28, 2023 by XframeFX (see edit history)

[Lee H]

5 hours ago, XframeFX said:

As for blowby, I'm on my 3rd PCV valve even thought the previous two were new and functional. I can't see how blowby would escape out the oil filler breather.

If your engine is a bit (or more than a bit) tired, you can definitely produce more blow-by than the PCV can handle. Especially if you run a lot of 70 MPH interstate miles.  In my quest to keep the original (now at 170k miles) engine in my ‘62, when I began to see evidence of oil staining on the firewall, and residue on the hood insulation (it wasn’t a closed system in ‘62 yet), I took a chance on an adjustable PCV, and that cleared the problem right up. They aren’t cheap, but they are very effective, at least if the blow-by is in the beginning stages.

 

https://mewagner.com/?p=444

 

[1965rivgs]

6 hours ago, XframeFX said:

Only solution for RH exhaust manifold to cyl. head leak I can think of is to use Hi Temp RTV. OK? Will not induce a crack as a gasket would? I'd have to remove the manifold in order to smear on sealant.

 

As for blowby, I'm on my 3rd PCV valve even thought the previous two were new and functional. I can't see how blowby would escape out the oil filler breather. However, I discovered a local 1963 Riviera with a mod for crankcase breather.

To do this mod, I'd require a 1964 - 66 valve cover with a hole at the front.

 

 

  Depending on whether you want a factory appearance or not you could simply find a breather with a nipple which installs where your present breather is and run a short hose from the breather nipple back into the air cleaner body or snorkel. Any blowby that escapes the breather will be consumed back into the engine's incoming air stream.

Tom

[NTX5467]

Yes, the referenced seal can work as a gasket for the exhaust manifold.  Dirt Track racers use it for header gaskets.

 

Using a reinforced header gasket should not result in a manifold crack.  Chevy originally had them for their '55 V-8s, then discontinued their use in later years.  Many overhaul gasket sets still had them in them, by observation, even if not needed.

 

The referenced item for the air cleaner just serves the same purpose as the open breather does on other engines.  Possibly that particular car had at one time been registered in California, where such might have been necessary to meet their emissions regulations?

 

The crankcase air enters through the breather, then exits via the road draft tube (which needs vehicle speed to operate).  In the transition time between a factory-designed pcv system and road draft tubes, Chevrolet had a system which could be easily added-on to their 1967 engines.  Basically a cap which went in the place of the draft tube, with a rubber hose connection on its top, asicde from the through-bolt which held it in place.  The rubber tube was attached to an inline pcv valve, which was attached to the rr base of the carburetor.  Those parts are probably in some repro vendor's catalog at this time, so you can get an idea of if they might work on a Nailhead.  OR might Buick have had some similar add-on system?  OR might an aftermarket system for the California market be available somewhere?  Or you could tap the road draft tube, below any internal baffling, for a hose to go to an inline pcv valve and then to a carburetor intake manifold vac tap?  No real need to use the breather as referenced in the picture, unless you might desire to.  When the pcv valve is added, the end of the road draft tube can be shortened, then sealed.  Again, check and see what might be needed for a California vehicle back then.  Seems like Chrysler started using factory pcv valve systems in 1963 or earlier?

 

The pcv valve will be closed (air directed through the internal drilled orifices in the spring-loaded valve) at idle, getting full flow with decreased manifold vac levels (as at or near WOT or under load).  Minimal affect upon idle speed or mixture settings, if any at all.

 

Chevy used two pcv valves later on, one for their normal engines and one for the LT-1/L82 Z/28 and Corvette engines.  The valve for the HP engines had a purple die where they plugged into the valve cover grommet, with a slightly higher flow rate.  I tried it on my '77 Camaro 305 after the cam and intake manifold upgrade, as a tuning device of sorts, but ended up going back with the normal system.

 

I ran across and SAE paper on early pcv work GM did, using two 1961 Chevy Biscayne 6-cyl security patrol vehicles.  Trying to determine which flow rates worked best to decrease sludge build-up inside the engines.  They determined that using two proposed valves, rather than one, decreased sludge a good bit, but they finally settled on the flow rate that became the production valve flow rate.  Seems like it was something like 1cfm, or between 1 and 2 cfm, more toward the l cfm rate?

 

End result, any pcv valve can work OK.  Chevy started with their inline valve on the '67 models, then went to the normal ones in '68, the plastic elbow can be removed, if desired.  1966 Chrysler 383s used a metal Stanadyne valve with a curved top connection, later to be replace by the plastic valves.  In those earlier systems, the breathers were open and filled with "hogs hair" as a filter.  The 1972 Chrysler items had the nipple for the air cleaner attachment with a flame arrestor and filter inside of it.

 

Another project for a long (compared to TX) winter season?

 

NTX5467

[gungeey]

7 hours ago, XframeFX said:

Only solution for RH exhaust manifold to cyl. head leak I can think of is to use Hi Temp RTV. OK? Will not induce a crack as a gasket would? I'd have to remove the manifold in order to smear on sealant.

 

As for blowby, I'm on my 3rd PCV valve even thought the previous two were new and functional. I can't see how blowby would escape out the oil filler breather. However, I discovered a local 1963 Riviera with a mod for crankcase breather.

To do this mod, I'd require a 1964 - 66 valve cover with a hole at the front.

 

 

If you are removing the manifold for the exhaust leak why not just take it completely out of the car. 

I've had good luck with a 44 Inch long plane made from two pieces of oak flooring (screwed together in a "T") that will accommodate 4 11" sheets of sandpaper or emery cloth in my choice of grit. 

The head side gets cleaned up with a carbide blade. The board dresses the sealing surface of the manifold. 

I use it on the intake, too

Works great👍 

[XframeFX]

7 hours ago, 1965rivgs said:

you could simply find a breather with a nipple which installs where your present breather is and run a short hose from the breather nipple back into the air cleaner body or snorkel.

Too late, discontinued. Push-On only:

 

Edited October 28, 2023 by XframeFX (see edit history)

[NTX5467]

With the referenced item, which will reverse the air flow through the crankcase, what do you propose to use to filter the air going into the crankcase?

 

Just curious,

NTX5467

[XframeFX]

New Clark's Leather and carpet being exposed to Nailhead stink. So, looking for Auto Leather protectant. What product? Similar to too many flavours of Pertronix, holding off. Sigh, more research, Neetsfoot Oil, Mink Oil, what?

Now this, I like how it mentions "SWEET SMELL" Protectant:

https://leatheriquecanada.com/

 

 

[EmTee]

https://www.amazon.com/Lexol-Leather-Conditioner-Cleaner-Kit/dp/B07LGVZLP9/ref=sr_1_1_sspa?crid=2DINRDZ09PLXA&keywords=lexol%2Bleather%2Bcleaner%2Band%2Bconditioner&qid=1698794959&sprefix=lexol%2Caps%2C108&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

[NTX5467]

Trying to overpower the fuel pump aroma with the leather aroma?

[gungeey]

Replace the lousy fume smell with this crappy aroma 😆 

 

 

[60FlatTop]

I was just looking back through this topic to refresh my memory.

 

That manifold picture makes me think your carburetor may be leaking. It is pretty black in those runners. It have seen Cadillac manifolds look like that when the passage plug on the base begins to leak. The best way to observe it is to run the car, shut it off, and quickly remove the carb. That gives you a good view of the wet manifold insides and you can hold the carb to see the fuel dripping.

 

If you have the AFB you would have the four lead plugs shown around the secondary throttle plates. One or more could be seeping. It was hard for me to catch the first time because the fuel evaporated quickly. When I was ready to pop the carb quickly I caught it.

[NTX5467]

Good possibility, BUT considering that they are separated from the throttle bores by a gasket, might that gasket also show signs of such seepage, as the fuel would congregate in those hollow areas, over time?  Time to get out the J-B Weld and seal them up like the well seals on a QJet?

 

NTX5467

[60FlatTop]

I have a pretty good stock of those interesting "parts of parts" but I do see NAPA is still stocking the plugs.

https://www.napaonline.com/en/p/CRB26?cid=paidsearch_shopping_dcoe_google&campaign=GSC-Fuel-Emissions&campaign_id=10951730297&adgroup_id=113117085528&adtype=pla&gclid=EAIaIQobChMIxv6-hJijggMVQUZyCh0YKQFGEAQYAyABEgIcAPD_BwE&gclsrc=aw.ds&

 

It is one of those instances where everything has been tried and I would choose not to assume anything is good.

 

The black in the manifold passages bothers me the most. Sitting here with my aging memory I can only picture that on leakers. Looks like carburized metal.

[EmTee]

Pay particular attention to the ones on the passenger side of the carburetor.

[XframeFX]

18 minutes ago, EmTee said:

Pay particular attention to the ones on the passenger side of the carburetor

That image was taken early in my troubleshooting where I was about to mount the $400 AFB rebuild. So, black (including all 8 sparkplugs) happened due to a leaking float needle. That float needle resolution was the only item that made a difference. Lots of work since and no change.

 

More work:

1) Run engine and scrutinize crankcase ventilation.

2) Resolve Exhaust Manifold Leaks.

3) Run engine, more troubleshooting/adjustments. Then remove AFB, inspect and possibly return to local rebuilder for re-do. But, not throwing any more $$$ at it.

4) Re-route crankcase breather intake to inside Air Cleaner, similar to emissions mod from back-in-the-day as shown in image near the top of this post.

5) Use only one gasket when mounting the next carburetor. Don't like that plate (image):