Any ideas? Still Rich!

[gmanrides]

I thought I had the dual 97's worked out but apparently not. My plugs are still carbon fouling. The mains are .042 and and I disconnected the pump rod and it still smells rich. Upon throttle it will smoke out of both banks. I used carb cleaner to see if I could detect any vacuum leaks but none found. I noticed each intake port had a puddle of fluid in it. At first I thought it was oil but not the same color so I dipped a rag and it smells like gas. There was no sealant on the intake gasket. Looking inside the spark plug holes they just look rich except for 1 & 5. I am going to run through valve adjustment while in there. Thanks Gary

 

[Charlie ny]

I will hazard a guess that one or more of your power valves are leaking, I'm hoping
monsieur Musgrove will join in here. Do not get a comfy feeling that new PV's don't
leak. There are ways of testing these jewels. I also make my own PV gaskets out of
nylon vs the semi hard fiber gasket, the nylon is plenty durable but will give some
and in my mind insures a better seal.
Charlie ny

 

[gmanrides]

Thanks Charlie, can you elaborate on testing the PV's? I just as soon go through everything while I'm at it. Thanks Gary

 

[alanwoodieman]

some people make up a small device where you can screw on the pv on one side and pump vacuum on the other. personally I would start by going to 35 jets on both carbs and make sure the pv,s are marked for 5.5. I have even plugged off the pvs and seen better performance and less gas usage with no seemingly power loss. we started with 45 on two separate engines with dual 97's and on both engines we ended up with 35 jets. Charlie ny is correct about the gaskets on pv's--they are hard to seal

 

[FlatheadTed]

Run the starter over with the carb top of and check the float/fuel level ,some rebuild kits have the needle valve housing to long so the float touches .and wont shut off .

 

[big job]

On pic #5 whats that dark spot I see on the intake gasket as well as the oil spot??

 

[Charlie ny]

gman,
Woodieman correctly describes the PV testing process for a 94 style carb.
On a Stromberg style carb with a mechanical/hydraulic PV I have a device that the
PV is threaded into. Fuel is filled into a well over the PV and leakage is observed.
Very simple but it works.
Charlie ny
PS
If you want to try the nylon gaskets let me know !

 

[Bored&Stroked]

I would definitely check your float levels - that is what I'd suspect the most. Are you seeing it rich at idle (like flooding) - or only when you open the throttle plates? At idle, do you see any gas coming out of the main dump tubes - up by the top? There should NOT be enough vacuum for any gas to be coming out the main venturi tubes and nothing should be seen in the accel squirters either. Essentially there should be no visible gas flowing inside the carb at idle (as only the idle screws are sending fuel) - way down in the cast-iron bases.

Do you have a fuel pressure regulator? About the max fuel pressure these carbs can take is 2 - 2.5 lbs. I usually set mine at about 1.5. If you have more, you'll be overflowing the floats and everything will be rich (and usually you'll see signs of weeping fuel on the outside of the carbs - around the top gasket).

Lastly, how are you checking your plugs? You can't check them with the engine running in the driveway . . . you have to get the car hot, run the car down the road at a decent RPM, push the clutch in and turn the engine off -- coasting to a stop, then check them before restarting the engine. With today's fuel - it is very hard to read plugs - but the above method will give you a chance at it.

 

[TerryOH]

Lots of good ideas above! What plugs are you using and what gap? What type of ignition system? What plug wires? Put a vacuum gauge on the engine to determine if the vacuum is low You can also use it to monitor fuel pressure and adjust the idle mixture adjustment. (don't guess). What size power valves.....69??? My car runs lean on 42 had to use slightly larger mains. You can remove the PV and check the gaskets to make sure they are seating and the gaskets should be slightly deformed like your intake gasket. You should have a metal tube from the bottom of the fuel pump adapter to the engine block. Maybe you just don't show it in your photos. When installing new fuel input needles and seats it is good to gently tap the needle into the seat. This will form the seat to the needle and allow better fuel shut off.

 

[john in illinois]

I had a rich problem with 2 97's. I checked everything I could and could not find the problem. I finally made a shim to block off 1 carb at a time. This will quickly show if the problem is one carb or both. In my case one was perfect and the other had a problem.

That is assuming your manifold has a common chamber like my Offy regular dual.

John

 

[BUBBAS IGNITION]

We can all speculate on the problem and the above posts show many approaches to the issue. The easiest and best thing you could do is to remove the carb and send it to Charlie and let him take a look, he runs them on a test engine and when returned its perfect and ready to run right out of the box...

 

[19Fordy]

As a side note, try using this on your intake manifold gasket.
I also use a light dab on carb base gaskets and threaded fittings.
Has a clear color, won't harden, oil, and is gasolene resistant.
Any excess wipes off easily. Good stuff.
http://www.aircraftspruce.com/catalog/cspages/ezturnlube.php?clickkey=42464

 

[gmanrides]

FH Ted: These carbs are fairly new and have not had a kit installed. I have checked fuel level and my pressure is a steady 2.5 psi.

Big Job: I noticed the oil as well and concerned about the seal or lack of in that area of the intake port. I also noticed the threaded holes between the intake ports were full of oil. The intake doesn't provide a bolt there but you would think the gasket would seal it.

Charlie: I will PM you for some of those gaskets.

Bored& Stroked: While idling no fuel visible looking down carb throats until you accelerate, no fuel regulator but gauge reads steady at 2.5psi. I am using the same type pump on a 392 Hemi with 97's with same readings and no issues. I am not seeing any leakage around top gasket. Plugs were just changed and virtually no drive time, previous set looked the same and I drove it like I stole it. LOL Ran good till carboned up. On one note it didn't smell rich like it does now or smoke like it does now either.

Terry: your right a lot of good suggestions, I'm not running stock fuel pump and the rod hole is plugged.

John: I like that idea of a block off plate.

Jim: The bright side is my crab is still throwing fire! LOL

19Fordy: After looking at the gasket I thought about putting a sealer on it. As of now I am going to run through valve adjustment and recheck the carbs and go from there and see what happens.

 

[Bored&Stroked]

Looking at your intake gasket - sure looks like a lot of core shift in the intake ports - wonder if you were sucking out into the one in the rear (where you have oil in the bolt hole as well?). I'd probably use a bit of 'gaskacinch' on the gasket and intake surfaces.

For you to have that much fuel in the intake ports, then obviously there is an excess of fuel coming into the motor. If you haven't rebuilt the carbs, then I would at least check the PV's and gaskets. Sounds like you're not flooding out the carbs will fuel pressure.

Questions: Did it used to run well and then this started happening? Or was it like this from get-go? Also, what plugs are you running?

Lastly, what are the specs on the rest of the motor? I can't see two 97's with .042 jets being that rich - even on a stock cubic inch motor.

 

[Charlie ny]

gman,
I'll get a couple PV gaskets headed your way.............in the mean time get
a hold of Max Musgrove and order ( from his inexhaustable supply ) a pair of tested
PV's. Max has the same device I have to test Stromberg PV's. For lots of reasons
this is the shortest way at this time to eliminate your problem, if it is as I suspect PV related.
Charlie ny
PS
PM me your address

 

[gmanrides]

Bored&Stroked: I have been fighting these dual carbs for some time but thought I had it licked when I went to .042 jets. Ran good initially with only a hint of black smoke on quick acceleration. Plugs are NGK B6L and looked good with only 3 & 6 showing a hint of carbon, 1 & 5 read the leanest. Coming back from a cruise in one night it started missing. Pulled plugs and all were carboned up except 1 & 5. Installed new plugs and of course thats not the issue. As far as engine it came with the car but I have all the paper work with it. According to machine shop receipt it was bored .030 and is suppose to have a 400JR cam in it. The last time I checked compression dry the left bank ranged 100-105 and the left bank slightly higher 110-115. I have a host of PV's and jets to play with but I am going to get a regulator for fuel pressure as well. I'll go back and check floats and PV's to see if I can determine cause.

Charlie: Thanks PM sent.

 

[Charlie ny]

Gman,
42's are as low as I would ever go, even with a stock motor. If your floats
are pretty much un-dented the ancient rule of thumb is to set them so the top of
the float opposite the inlet is 1/16 lower than the top at inlet side, a barely noticable droop. Since there is no flooding issues it appears as though the inlets are doing their job. An obscure thing to check is the 90 degree bend on the float tang. At times this
bend can interfere with 100% sealing of the needle and seat, that's a stretch though since I'd think you'd be flooding over, but no stone left unturned.
If you wish send me your PV's and I'll check them.
Don't forget Max Musgrove.
Charlie ny

 

[gmanrides]

Thanks Charlie, I have dealt with Max before he did a couple of old 97's I have and done a fine job! I think I have a total of 8 97's but not all are functional. I have four on a hemi but the outside's are dummies running off the center two. That one had issues but were due to too much fuel pressure and incorrect float level. It runs .045 and 65 PV's. I have another Flathead in the engine run stand that is a 8BA .060 with Merc rods and crank and a single 97. I should have plenty to figure it out just hate to rob Peter to pay Paul. I also have a block off plate and could try isolating after I go through them if I'm still having issues. I'll see what I come up with this weekend when I get my garage time. lol.

 

[gmanrides]

First off a Big Thanks to Charlie NY for the PV gaskets and your truck is Gawgis! Looks like a Bubba's dizzy on there.
Well the following is what I did and where I am at:
I went through valve adjustment since the intake was off, some were as far as .010
loose and a few were a couple thousands tight. I set all the intakes at .012 and exhaust at .014. I replaced intake gasket with a coat of gasgacinch. I went through both carbs checking everything and even removed discharge nozzles. Still do not quite understand when they say to check the nozzles for damaged holes from over-tightening of main jets. All 5 holes were fine along the tube. Anyway once I had everything back together except for the tops of carbs I ran the fuel pump and gauge was showing 2.5 psi then all of a sudden it shot up to 4 psi. Hmmm, installed pressure regulator which say it adjust from 1-4 ps. Never could achieve 1-1.5 psi even had adjuster screw all the way out hovers around 2 psi, Bored & Stroked curious which fuel regulator do you use? Anyway fairly happy with fuel pressure, floats are set at 1/2" but I noticed front carb the level was higher. Adjusted tang on float, it would still rise slowly. These carbs came with S-Jet inlet valves. So I put another one in and same thing. I finally gave up on it and put a regular needle and seat in it and presto no more rising fuel. Current configuration is 69 PV's and 42 mains. Starts up and idles better than ever @ 500 rpm, throttle no load sounds good. Test drive lacking fuel on acceleration, falls on it's face. I can feather it and keep it rolling on down the road, going from S setting to W helped somewhat but not quite there. Carbs uni-synced just fine. Idle jets 1 turn out. vacuum at idle bounces 9-10 rev it up 1500-2000 rpm and it climbs and steady around 20. Not sure how accurate vacuum is due to the only provision on the intake pulls at #5 or #8 intake port. Not sure what you guys think but Maybe I should try the 43 mains and give her another run? Thanks Gary

 

[Charlie ny]

Gman,
I'd do the jet switch pronto, I know Max likes 43's even 44's.
It is a great compliment that my sbc / 8ba distributor looks like one of Bubba's
but it is actually one of the ones I build.
Holley reg is the only one I use.
Charlie ny