Cylinders 1 and 2 out to lunch

chitwnvw · Post by **chitwnvw** » Mon Apr 23, 2007 10:07 pm

Got my engine back in. Fired it up and the engine is bucking around, what the!? It ran fine before I pulled it.

I pull the plugs wires to see who's doing what and pulling the wire from #1 has no effect. Pulling #2 has a minor affect, pulling #3 and #4 almost kill the engine.

While the engine was out, I reset the floats from 9 mm to 10.5 mm, but that's about it. When I sprayed carb cleaner at the base of the carbs, no effect. When I sprayed a bit of carb cleaner into the air intake of 3 and 4 it almost killed it, but on 1 and 2, no effect. Checked spark for 1 and 2 and both are getting spark.

OK, I'm going to check the valves tomorrow, I set them before installing the engine, but who knows. I'm going to pick up a timing light, cause my harbor freight special seems to have given up the ghost. Any other things to check?

Help me brainstorm. Thanks.

vwlover77 · Post by **vwlover77** » Tue Apr 24, 2007 5:07 am

Do you have the spark plug wires crossed?????

1-4-3-2 as you go clockwise around the distributor cap. It may look weird when it's right because the 1-2 wires may cross over each other on their way to the cylinders.

vdubyah73 · Post by **vdubyah73** » Tue Apr 24, 2007 5:16 am

x2, on the above, easy mistake to make, I've done it a time or two. If you had the carbs off, it's probably the linkage though. Disconnect the linkage and start over with carb synchronization, and adjustment of the down arm lengths. There is a little wiggle room in the head to manifold studs and the carb to manifold studs as well, you never get it back together exactly like it was.

Bill

Post by **Amskeptic** » Tue Apr 24, 2007 1:56 pm

Dual carbs dead side of engine problem often is a dirty cut-off solenoid jet. . . or even a little backfire that blew the booster elbow slightly ajar.
Colin

chitwnvw · Post by **chitwnvw** » Wed Apr 25, 2007 8:04 am

Unhooked the linkage, and that seemed to bring #2 around. Number 1 though is still not pulling it's weight.

vdubyah73 · Post by **vdubyah73** » Wed Apr 25, 2007 8:20 am

Junk in your carbs shaken loose and now plugging #1 idle circuit. Try adjusting the mixture screw for the #1 barrel first, may be a lean or rich mixture so do the lean best idle routine on it. If no response take out jet and spray carb cleaner, with the red tube, through the jet and stick the tube in the jet hole and and spray as well. May as well take the mixture screw out and spray in that hole as well. Don't lose the O rings. Reassemble and start the lean, best idle procedure with the mixture screw 1 1/2 to 2 turns out. If it clears up the problem, readjust your linkage and you're good to go.

Bill

chitwnvw · Post by **chitwnvw** » Wed Apr 25, 2007 2:11 pm

Hmm, sprayed out the jet and corresponding hole and the mixture screw as well. No difference.

How can I tell if it's fuel or spark that's lacking. If it's fuel and I spray starter fluid down the throat, should it then start firing?

vdubyah73 · Post by **vdubyah73** » Wed Apr 25, 2007 3:21 pm

Little carb cleaner down the throat, or pull the plug wire off the dissy cap while running and hold it close to the cap nipple you should see a spark jumping.

Bill

chitwnvw · Post by **chitwnvw** » Wed Apr 25, 2007 6:30 pm

Spark is jumping.

Carb cleaner down the throat of #1 no effect, on 2-4 it bogs them down.

Some strange behavior, the 1/2 side seems happiest with the idle mixture screw all the way closed on 1 and maybe 1/3 to 1/2 out on 2, it used to be happiest at 1 to 1 1/2.

vdubyah73 · Post by **vdubyah73** » Thu Apr 26, 2007 3:45 am

Did you plug intake ports with something while it was apart, then forget to remove it? Check your valve adjustment On #1 maybe to tight= no compression, maybe way loose = no intake event.

Bill

Post by **Amskeptic** » Thu Apr 26, 2007 9:27 am

chitwnvw wrote:Spark is jumping.

Carb cleaner down the throat of #1 no effect, on 2-4 it bogs them down.

Some strange behavior, the 1/2 side seems happiest with the idle mixture screw all the way closed on 1 and maybe 1/3 to 1/2 out on 2, it used to be happiest at 1 to 1 1/2.

I hate being the idiot late to the party. What carbs you got?
Colin

vdubyah73 · Post by **vdubyah73** » Thu Apr 26, 2007 12:58 pm

IDF's , 40's I believe, I'm close to getting stumped on this one. Help a fellow out here, Colin.

Bill

chitwnvw · Post by **chitwnvw** » Thu Apr 26, 2007 7:16 pm

Yes, dual weber 40 IDFs.

Check for paper towel in the intake. No go. I thought that idea had some promise.

I checked the valves at tdc #1, didn't get under there with a blade and check for .006, but they both had a little play.

Ran a compression check. Engine was warm and left other plugs in. I got 45 psi on my gauge. That's no good.

I do have a slight problem now in that my compression tester doesn't want to unscrew. You have to dangle the metal part that goes into the spark plug hole down into the tin with a flexible rubber hose, and spin the gauge and rubber hose around to thread into the spark plug hole. Now the rubber hose is spinning but not the metal part that goes in the plug hole.

vdubyah73 · Post by **vdubyah73** » Fri Apr 27, 2007 8:27 am

I see from your Samba post that you had the heads off. Did you keep the cylinders married to their original heads? You may need to tear it back down. Something prolly went wrong upon reassembly. While it's apart, lap the cylinders to their respective heads. Maybe you'll find that paper towel in there.

Bill

chitwnvw · Post by **chitwnvw** » Fri Apr 27, 2007 2:34 pm

Ok, I think I've found something.

With the engine cold, I ran a compression test on #1 and get around 100 PSI with my compression tester, but if I run for 5 minutes and test, I'm getting 45 PSI. So obviously when it warms up a bit something is loosening. I assume it's the mating surface 'tween the heads and the cylinders.

What's a good way to handle it. Should I pull the engine and tear that side down? Or should I first try to untorque the head bolts on that side and try and find a better seat, then retorque?

Itinerant Air-Cooled

Itinerant Air-Cooled

Cylinders 1 and 2 out to lunch

Cylinders 1 and 2 out to lunch