Carb Flatulence? (1 Viewer)

[Anvil]

Really need some help here folks...

Today may 1.5F with Weber carb died while idling. When I turned the ignition key, the engine attempted to start. After a couple of cycles of the engine, it died again, then there was a "fluttering/flatulence" sound for 3-4 seconds, which produced a significant amount of vapor escaping through the louvers of the hood (I assume from the carb).

This happened twice in a row. I let the engine set for a few minutes, she fired up and idled fine.

What the heck happened and how do I repair it? I want to fix this problem before taking on the road again. I truly have NEVER heard an engine make this sound!

Any help will be much appreciated! Thanks!

 

[Pin_Head]

Try feeding you carb less red beans and more rice.

More seriously, I don't have a clue about what you are talking about.

 

[shawnfj40]

Next time your weber does that, pull the air filter and see if your choke is locked on. I have had an issue before where the choke plate sticks in the bore. Beyond that Im with pinhead.

 

[JohnnyC]

Which weber? 32/36 or 38

What type of ign sys? Stock points?

The sound could be when the piston is on compression stroke and its leaking past the intake valve

When have you adjusted the valves last? Changed cap, rotor, wires, points, condensor, Pcv, air cleaner and replaced plugs or cleaned them? adjusted timing?

In other words ... When have you gave it a full tuneup?

Check for vac leaks yet?

 

[65swb45]

Which weber? 32/36 or 38

What type of ign sys? Stock points?

The sound could be when the piston is on compression stroke and its leaking past the intake valve

When have you adjusted the valves last? Changed cap, rotor, wires, points, condensor, Pcv, air cleaner and replaced plugs or cleaned them? adjusted timing?

In other words ... When have you gave it a full tuneup?

Check for vac leaks yet?

All fair questions if you want more than WAG.

 

[Anvil]

Sorry for the slow response. I spent yesterday fishing and crabbing with friends.

I appreciate the replies! I'll try to be more accurate with description in this post. One thing I need to add. When this problem occurred, there were two other - mechanics who observed this. We were all scratching our heads, thinking "wtf", especially after the steam/vapor/smoke(?) bellowed out from the drivers side louvers. Unfortunately, by the time we raised the hood, it was too late to locate the source.

This 1.5 F typically runs great! I have driven it over 40,000 miles and know the engine well.

The engine has a 38 Weber with an electric choke, that I rebuilt almost a year ago. Two weeks ago the engine would not start. I removed the air cleaner, placed a piece of cardboard on top of carb... the engine immediately fired up. Though I have adjusted the electric choke, I plan to replace it with a manual choke this weekend.

Three years ago, after the original dizzy began burning up points every 200 miles... I installed an Hei (79 Camero). In the past year, I have gone through 3 coils and 5 modules. The last coil/module lasted less than 80 miles . The day this problem occurred, I had installed an external coil, thinking the coil was getting hot and destroying itself and the modules. I believe the external coil installation was done correctly, because it starts and revs fine. Though occasionally it will die while idling without warning, thus the problem.

I have rebuilt the HEI dizzy, all parts are new. Plugs and wires are new.

The valves have not been adjusted in quite some time.

Today I plan to check for vaccuum leaks using carb cleaner. I did this a year ago and repaired all leaks.

Timing will be checked/adjusted today. Though it was checked two weeks ago.

One last thought just occurred to me... two months ago the fuel pump went out and left me stranded. I was forced to install an electric fuel from AutoZone. The pump produces 2.5 - 4 lbs. of pressure.

I LOVE driving the 40... but until I find the source of the intermittent dying, she's staying in the shop.

Again, any advice is much appreciated! Thanks!!!

 

[Weber Sarge]

Ditch the HEI and use a Toyota distributor or get one from Trollhole , as well as install a stock fuel pump . Those chevy distributors never seem to work correctly and love chewing up camshafts . The electric pumps out there are junk unless you want to spend close to $400 for a proper one that actually works consistently . For the 38DGAS and a stock pump you can either add a bypass at the carb or use a bypass type fuel filter like the ones used on CJ series jeeps and plumb it back into the tank return . These seem to work the best and are consistent at delivering lower pressure to the Weber .

Don't ditch that electric choke - it's the most reliable one on the market and easy to adjust once you understand it . The manual conversion kits are a hack job and usually result in binding up or breaking . It sounds like from your description the choke isn't adjusted tight enough to work correctly when cold - need more info on exact procedure you use to start the engine first time of the day ...
Sarge

 

[Anvil]

Sarge, I agree with the Toyota dizzy statement and plan to do that on the 79 2F (with 74 head) that I plan to rebuild this spring.

I found a huge vacuum leak under the Weber. Had gaskets on hand, and think I fixed that...

When setting the timing, the vacuum advance would hit the stainless dual battery tray. I I decided to move the dizzy counter clockwise 60 degrees and move my wires counter clockwise by one hole. Now she want start at all.

When I have #1 piston at TDC on compression stroke, my rotor is pointing between #1 and #4... How did this happen? How do I fix it?

I'm taking off work tomorrow to finish this... so any advise regarding the diizy will be much appreciated! Thanks again!!!

 

[Pin_Head]

Turning the distributor body only 60 degrees CCW and then moving the wires over one hole should give the same approximate timing. You may need to move the distributor back and forth while cranking to get it in the starting range.

If you moved the whole distributor including the gear 60 degrees CCW, and then move the plug wires over hole, your timing will be way off.

 

[Anvil]

Thanks Pin!

I'm a little confused (easy to do!). Here's what I did...

Loosened clamp

Turned dizzy 60 degrees counter clockwise (did not pick up/disengage gear)

Moved wires 1 hole counter clockwise

Is this the correct procedure?

If this is the correct procedure... why is the rotor pointing in between the 1 and 4 wires on the cap?

Thanks again!!!

 

[sggoat]

Sorry for the slow response. I spent yesterday fishing and crabbing with friends.

I appreciate the replies! I'll try to be more accurate with description in this post. One thing I need to add. When this problem occurred, there were two other - mechanics who observed this. We were all scratching our heads, thinking "wtf", especially after the steam/vapor/smoke(?) bellowed out from the drivers side louvers. Unfortunately, by the time we raised the hood, it was too late to locate the source.

This 1.5 F typically runs great! I have driven it over 40,000 miles and know the engine well.

The engine has a 38 Weber with an electric choke, that I rebuilt almost a year ago. Two weeks ago the engine would not start. I removed the air cleaner, placed a piece of cardboard on top of carb... the engine immediately fired up. Though I have adjusted the electric choke, I plan to replace it with a manual choke this weekend.

Three years ago, after the original dizzy began burning up points every 200 miles... I installed an Hei (79 Camero). In the past year, I have gone through 3 coils and 5 modules. The last coil/module lasted less than 80 miles . The day this problem occurred, I had installed an external coil, thinking the coil was getting hot and destroying itself and the modules. I believe the external coil installation was done correctly, because it starts and revs fine. Though occasionally it will die while idling without warning, thus the problem.

I have rebuilt the HEI dizzy, all parts are new. Plugs and wires are new.

The valves have not been adjusted in quite some time.

Today I plan to check for vaccuum leaks using carb cleaner. I did this a year ago and repaired all leaks.

Timing will be checked/adjusted today. Though it was checked two weeks ago.

One last thought just occurred to me... two months ago the fuel pump went out and left me stranded. I was forced to install an electric fuel from AutoZone. The pump produces 2.5 - 4 lbs. of pressure.

I LOVE driving the 40... but until I find the source of the intermittent dying, she's staying in the shop.

Again, any advice is much appreciated! Thanks!!!

I think the key here is the 4th paragraph. You say the truck wouldn't start 2 weeks earlier until you "choked" it with a piece of cardboard.--that tells me the elec choke has prob failed. The visible "flatulence" is very likely a slow backfire in the carb-out the intake--causing the visible vapor. My 38 does this on occasion(I don't have the choke hooked up), but it will tend to do it if it's cold and you punch too much gas in it - essentially the same as choking it)
I would look into the elec choke first thing

 

[Pin_Head]

... why is the rotor pointing in between the 1 and 4 wires on the cap?

!!!

That is approximately correct. Worry about it after you get it started and running good.

 

[Solace in Solitude]

@Anvil --- That's why @Pin_Head said, "You may need to move the distributor back and forth while cranking to get it in the starting range." HTH

 

[Anvil]

I think the key here is the 4th paragraph. You say the truck wouldn't start 2 weeks earlier until you "choked" it with a piece of cardboard.--that tells me the elec choke has prob failed. The visible "flatulence" is very likely a slow backfire in the carb-out the intake--causing the visible vapor. My 38 does this on occasion(I don't have the choke hooked up), but it will tend to do it if it's cold and you punch too much gas in it - essentially the same as choking it)
I would look into the elec choke first thing

Thanks for the input! I installed a manual choke today... I forgot how much a missed pulling that knob!

That is approximately correct. Worry about it after you get it started and running good.

Rodger that!

@Anvil --- That's why @Pin_Head said, "You may need to move the distributor back and forth while cranking to get it in the starting range." HTH

Tried it earlier ... I'll give it another go tomorrow.

 

[Anvil]

I've been attempting to time this engine, after moving the dizzy 60 degrees CCW and the plug wires 1 step CCW, for the last 2 hours.

I'm confident the dizzy is in the 60 degree range. I used a protractor and made a template!

I'm getting spark to the plugs.

Moved dizzy back and forth slowly... still no start. I'm now charging the battery.

Why is my carb spitting? I have a video of this, but can't figure out how to attach it. I'll keep trying.

Any help is much appreciated! thanks!!!

 

[Pin_Head]

Static time it:
Put the engine on the BB ( 7 degrees BTDC) for the compression stroke of #1.
Pull the coil wire and place the end close to ground.
Turn the key on.
Retard the distributor about 20 degrees.
Advance the distributor slowly just until it makes a spark.
Start it and adjust timing.

Carbs spit back through the carb because of misfiring; either due to a lean condition or ignition while the intake valve is open. Are you sure you don't have the distributor 180 degrees out? Make sure that #1 is coming up on compression stroke when the rotor is pointing to #1.

 

[Anvil]

Thanks Pin! I appreciate and value your help! Your a great service to this community. I'll give this a try...

Retard is counter clockwise? (I'm beginning to feel a bit retarded myself).

 

[Anvil]

Oops! I meant clockwise retards... Correct?

 

[Pin_Head]

Correct.

 

[Anvil]

WOOHOO! She purrs like a kitten again!!!

For future reference for folks wanting to reposition the distributor...

Move the dizzy counter clock wise in 60 degree increments.

Move the plugs wires CLOCK WISE one hole for each 60 degree increment!!!

This was my problem all along... DO NOT MOVE THE DIZZY AND PLUG WIRE COUNTER CLOCK WISE, AS ADVISED IN PREVIOUS POSTS!!! This is WRONG! WRONG! WRONG!

I repositioned my plug wires clock wise and the engine started the the first try! I could have had this problem solved in 20 minutes...

Cheers!