Carb trouble

[76classic]

Yes. The smaller brass tube inside the double ring. That is the primary main nozzle.

Fuel dripping out here is because you had to bump up the idle speed screw to open the throttle plate because it isn't getting enough fuel, probably due to a vacuum leak because the idle fuel circuit is providing some fuel.

Thanks so much for helping me identify the problem. Gonna go chase that vacuum leak and let you know the result.

 

[Pin_Head]

Try re-torqueing the manifold and check for other large leaks, like the EGR, the brake booster, manifold cracks. You can also use carb cleaner or propane gas to find leaks.

 

[76classic]

Try re-torqueing the manifold and check for other large leaks, like the EGR, the brake booster, manifold cracks. You can also use carb cleaner or propane gas to find leaks.

Think I found a leak in the mainfold. Of course it's way in the back. Gonna be a long couple days. Thanks again for all your patience. I'll give ya updates as I go.

 

[76classic]

Think I found a leak in the mainfold. Of course it's way in the back. Gonna be a long couple days. Thanks again for all your patience. I'll give ya updates as I go.

Quick question though. With the Holley carb, the 40 stuttered at acceleration also. Think it was the same problem? Started fine.

 

[thebigredrocker]

Try stacking a few washers under your accelerator pump cotter pin.

Also, I noticed your AP linkage is on the inside of the bell crank doo-hicky Guessing it won't matter if you flip it, thought I'd point that out.

 

[thebigredrocker]

Did you see fuel spray from the nozzle at idle? What's your vacuum reading? Have you checked your intake and exhaust valve lash?

 

[Pin_Head]

Quick question though. With the Holley carb, the 40 stuttered at acceleration also. Think it was the same problem? Started fine.

Probably the same issue, especially if it stumbles off idle.

 

[76classic]

Did you see fuel spray from the nozzle at idle? What's your vacuum reading? Have you checked your intake and exhaust valve lash?

Thanks for the tip on the AP linkage doohickey. Have not checked vacuum. Did find what I think is a leak from exhaust manifold. Was planning on going back to stock exhaust manifold anyway, which I have original, so I may as well do that at the same time I do the gasket on the intake.
I actually have ALL original smog equip also. Was thinking I should put it all back on. In that case I would 100% original under the hood. The rest of the truck is bone stock. The top has never even been off this thing. Not sure what you mean by "intake and exhaust valve LASH"

 

[thebigredrocker]

Valve lash is another way of describing checking whether your intake valves are closing to early, late or precisely when your spark plug ignites the air/fuel mixture which is usually 7 degrees before TDC(top dead center) of the compression sroke. And then obviously your exhaust valves need to be closed during to compressed explosion to make power and open at just the right time to let the burn fuel escape. Just from reading old posts of cruiser heads, the valves need to be checked from time to time.

There is a good thread in FAQ on Valve adjustments. Main thing is have your engine good and warm. Some guys follow the FSM and check while the engine is running. Some who seem knowledgable quickly check with the engine off. I follow FJ40Jims advice to put the rig in 4th gear, then push the rig to move #1 piston or #6 piston into TDC during static adjustments.

 

[76classic]

Valve lash is another way of describing checking whether your intake valves are closing to early, late or precisely when your spark plug ignites the air/fuel mixture which is usually 7 degrees before TDC(top dead center) of the compression sroke. And then obviously your exhaust valves need to be closed during to compressed explosion to make power and open at just the right time to let the burn fuel escape. Just from reading old posts of cruiser heads, the valves need to be checked from time to time.

There is a good thread in FAQ on Valve adjustments. Main thing is have your engine good and warm. Some guys follow the FSM and check while the engine is running. Some who seem knowledgable quickly check with the engine off. I follow FJ40Jims advice to put the rig in 4th gear, then push the rig to move #1 piston or #6 piston into TDC during static adjustments.

Sorry for my inexperience. I just had the valves adjusted because they sounded a bit ticky (?). Nice and smooth now. I believe the timing was fine also.

 

[thebigredrocker]

Oh shoot don't be sorry, I pretty much have to search or ask how to do everything. That's great your valves are go to go.

 

[76classic]

ok, heres a quick one, I hope. Removed intake manifold. Just had a machine shop index it. Worst difference between low and high points was 20 thousandths. Can I get away with a good quality gasket or do I need to have this thing ground? If I machine it, I probably have to have exhaust manifold done also right?

 

[thebigredrocker]

No idea if 20 Thousanths is too much. I do know from all my searching that Mark W is a cruiser guru and he uses Fel-Pro gaskets dry. He also mentions doubling with good results.

You'll find all sorts of differing opinions. I ended up choosing to try the Fel-Pro method.

Here's a link to Mark W's comments:

Double manifold gaskets?

 

[76classic]

Ok, here's the update. Pulled exhaust header and intake manifold. Replaced gasket with Remflex. Torqued to 25 lbs. Still stumbles off idle until warmed up. Tested vacuum. 18 inches holds steady. No vacuum leak I suspect with that reading. Once warmed up I took it for a ride. No stumble in first and second gear. When i go to third gear when climbing a hill, bam, total loss of power. Any ideas.

 

[Pin_Head]

Stumble when cold is normal. Use the choke until it is warm.

Total loss of power going up hill sounds like fuel starvation, but that should include bucking and spitting.

If it is a steep hill and the float level is too high, gas might be pouring out of the bowl vents causing a loss of power.

It could also be electrical misfire, which feels different from fuel starvation.

Remflex gaskets work well in my experience.

 

[76classic]

Stumble when cold is normal. Use the choke until it is warm.

Total loss of power going up hill sounds like fuel starvation, but that should include bucking and spitting.

If it is a steep hill and the float level is too high, gas might be pouring out of the bowl vents causing a loss of power.

It could also be electrical misfire, which feels different from fuel starvation.

Remflex gaskets work well in my experience.

Yes, bucking and spitting, that's a good description. I noticed that the fuel level in the window is about a quarter full. Should it ALWAYS be at the dot. If that's the case then my Leblanc is too low. Is that simply a float adjustment?

 

[Pin_Head]

It is insufficient fuel flow under conditions of high fuel demand.
Causes are:
1. Dirt / rust in the tank.
2. Plugged fuel filter.
3. Bad fuel pump.
4. Carb inlet filter screen obstructed.

It is usually #1 which causes #2.

 

[76classic]

It is insufficient fuel flow under conditions of high fuel demand.
Causes are:
1. Dirt / rust in the tank.
2. Plugged fuel filter.
3. Bad fuel pump.
4. Carb inlet filter screen obstructed.

It is usually #1 which causes #2.

Brand new tank
Brand new fuel filter
Original fuel pump. Will check
Carb just rebuilt so filter screen sb ok.
Guess I'll chase the fuel pump issue.
I thought someone had mentioned float level adjustment would cause low glass level.

 

[Pin_Head]

Why not measure the fuel delivery first. Remove the coil center wire and the fuel inlet pipe at the carb. Stick the pipe into a bottle and crank the engine for 15 seconds. You should get at least a half a cup of fuel.

 

[76classic]

Why not measure the fuel delivery first. Remove the coil center wire and the fuel inlet pipe at the carb. Stick the pipe into a bottle and crank the engine for 15 seconds. You should get at least a half a cup of fuel.

Ok. I'll do that and report back. Thanks so much pin_head