ENGINE GURUS - First Spring Engine Start - Sum Ting Wong

[Terry Stapley]

418W - MSD 6AL - Pro Billet Dizzy - MSD Blaster Coil - Holley 750 DP

I started the engine for the first time since December last evening and it is not running right at all. The only winter projects I have done to the Cobra were new brake pads, some suspension stuff and I added a fan shroud!! No work on engine

Symptoms: Runs VERY Rough / Lots of Black Smoke from exhaust / Rear header pipes on both sides are not as hot as the front three, Pass. side rear tube is almost cool.
I did not have a lot of time to diagnose but I did pull the back drivers side spark plug and had it laying on the header as I cranked the engine. Very good spark. The plug was wet when it came out!!
I have 7 psi of fuel pressure at the carb and the engine was running fine when shut off in December. I added Stabil to the tank then also!
To me it seems like a fuel issue but I would appreciate any all advice as to what it might be and how to fix it!!

[Chaplin]

Are one of your floats stuck open? Look down the carb with the motor running and see if it is dumping fuel into the manifold.

[Terry Stapley]

I looked in the carb with the engine running (Roughly) and could not see any fuel dumping!! I also took out the sight plugs and the fuel level was at the bottom of the holes on both the primary and the secondary!
Thanks and sorry I forgot to put that in the thread!!
Any other ideas???

[jhv48]

Pull all the plugs and clean them.

Reinstall and try again.

You have a fuel issue. If the floats are properly filled and not leaking, it should fire right up and clean up when warm.

If they foul out again, and they are getting spark, drain fuel tank, lines and float bowls, clean plugs again and then fill the tank with fresh fuel. Prime carb and then monitor fuel pressure to make sure it is not over powering the floats. Look into the carb throat using a mirror so your face isn't over the carb. Have someone crank the starter for you while you watch for excess fuel flowing into the manifold. Should fire right up and run right!

The only variable was the fuel additive. Probably the culprit!

[RedBarchetta]

I'd pull the needle and seat assemblies from both carb bowls just to make sure one of them isn't hanging open. Then re-set the float levels a little low to ensure you don't get an overly rich condition upon restart. Assuming that makes things better and you get a clean idle, then reset the float levels to their proper (higher) height.

-Dean

[Ron61]

Terry,

Make sure that your needle valves and the float levels in the carb aren't stuck. I had that happen once in mine and even with the additive, they stuck. Took out the valves and cleaned them and everything was fine. The plug being wet would seem to indicate you may be getting to much gas to the cylinders, especially under idle and maybe flooding them.

Ron

[mr0077]

And instead of cleaning the plugs, you might want to replace them, as a bad flooding condition will sometimes kill one or two (plugs).

[undy]

If you have a compression gauge handy I'd check that wet cylinder, just to be sure.

Dave

[wtm442]

After replacing plugs, if you still have problem, take off the dizzy cap and wipe the inside so its clean and dry. Maybe some moisture inside. Then start engine inside garage with all lights off and cover any windows ... any sparks jumping from the wires?

[DAVID GAGNARD]

[quote=wtm442;824455]After replacing plugs, if you still have problem, take off the dizzy cap and wipe the inside so its clean and dry. Maybe some moisture inside. Then start engine inside garage with all lights off and cover any windows ... any sparks jumping from the wires?[/QU

zacctly, I've found with MSD distributors, the contacts on the inside of the cap corrode quickly and easily when left sitting for long peroids.....take off the cap and hit each connection with a small wire brush as well as the rotor, blow dry the inside of the cap and try it again...........at night...........

David

[jhv48]

If that were the case, he wouldn't have spark at the spark plug. Which he says he does.

Start with the simple things first. Weed out the variable (additive) and go from there. If you get spark to the plugs (and no one has screwed around with the firing order) then it's a fuel problem.

It's always something simple!

How much Sta-bil did you add? One ounce for 2 1/2 gallons of fuel is recommended.

[Tim Brewer]

My car does the same thing when it's time to change the plugs. I can always just "blow it out" on a straight-a-way and then it runs fine. But, I can tell you from experience, you can never clean plugs and expect them to last for any period of time. If you take the time to remove your plugs, it's easier to reinstall new ones.

[Rick Parker]

Spray some carb cleaner in the small brass air bleeds at the tops of the carb main body. Also as stated, check the distributor cap for moisture that will create crossfiring.

[trularin]

IMHO, the car is blowing black smoke...there is too much gas. May I suggest:

1. make sure the choke is not too closed that no air is getting past it. After sitting for two or three months, it make stick.
2. Did it backfire when you were starting it? If yes, is it possible you blew the Power Valve check ball into the frame so hard that it has not let go? In other words, the power valve may be stuck open ( no vacuum ).
3. If the float levels were off or bad the gas dumps at the bowl vents. Is there gas there?
4. Once the excess gas is fixed, the plugs will be fouled. May I suggest you remove them and clean them/replace them.

Just my opinion.

[speed220mph]

Terry, If it's a Holley you're dealing with, know that they don't like to sit. A backfire will cause problems, too, such as blowing out the power-valve diaphragm. Check it the engine backfired when staring it. As for the float bowls, they eventually drain over time, causing the gaskets at the float bowls and/or metering blocks dry out, which will cause internal leaks. If the floats and needle seem to be working--pull the sight plugs to see if the fuel level is correct--procede to step two. SNUG the float-bowl bolts. If they feel very lose, chances are you've found the problem. Beware: Over-tightening these bolts will bend the main body of the carb. This can be fixed, but it's a pain. Run the engine to see if the problem is corrected.

If snugging the float-bowl bolts doesn't work, remove the bowls. metering blocks and scrape clean the gasket surfaces. Here's come the pain part. Check that the carburetor surface the metering block seals against is perfectly flat using a small straightedge. A 6-inch machinist scale will work. Just lay it again this surface in several directions, looking to see that there's no light between the rule and surface. If it appears to be bent or warped, file flat this surface. Be careful here. This operation must be done with the carb off the engine and on a bench. Some wet-or-dry sandpaper on a flat surface works, too. Run the carb body back and forth on the paper and look for high spots . . . they'll be bright. File or sand until the full face of the gasket surface is clean. Now reinstall the whole mess with new gaskets, install it on your engine and see how she runs.

[Terry Stapley]

I did not have time last evening to work on it but I will:

Change the plugs first thing

Again inspect and wipe the inside of the distributor cap

Leave the electric fuel pump on and look in the carb to see if fuel is leaking

Turn off garage lights to see if any Spark Plug Wires are arcing

Cross fingers and start engine!!

I will report back when these items are completed!!

Thanks for the advice!!

[wtm442]

Terry
Start the engine b/4 looking at possible wire sparking to grounds instead of plugs.

[Excaliber]

It's the carb all right, got 'sticky' from sitting around during the winter. Take it out and drive it like you stole it, maybe you'll get lucky and the carb will clear up. Could be stuck power valve, for instance.

[CHANMADD]

I doubt that it is Carb. It could be cross arcing in the distributor cap or the wires going to no: 4 and 8 which are next to each other in the cap. If it was the carb all the plugs would be wet.With all the trouble people are having with the MSD ignition I must ask if you have checked the clearance between the center electrode and the distributor cap?... making sure that that actually touch, and check that electrode at the same time for erosion.

[Terry Stapley]

By "Center Electrode" do you mean the spring steel piece that sticks up from the rotor to contact the center of the distributor cap.
If so I did not check that when I pulled the cap off the other evening