The Ford Barn

Speedbump47 · 09-14-2021, 03:43 PM

G'day All
I have been advised that the knowledge of the members on the site is beyond approach and can help solve anything!

Recently purchased a 1948 Mercury 100 HP V8 with 6 volt positive electrics.

The engine has a bad flat spot when accelerating, the PO gave up trying to solve after many tries. Looking for help to resolve as it is annoying and sometimes can be a problem.

Since I've had the car the following have been changed:
Plugs, wires, crab cap and rotor.
Petronix ignition and coil.
Rebuilt the model 59 carb following Mikes carbs on Youtube.
New battery.

Actions and observations:

Distributor brake connected and disconnected - no difference either configuration.
Intake and cylinder head bolts retorqued, no vacuum leaks detected.
Vacuum gauge reads steady 11psi, never changes despite fuel/ignition changes. Swings to zero back to about 18-20 when flipping accelerator then back to 11.
Mixture screw can be in all to way or out all the way but no difference to vacuum reading or engine idle.
Ignition timing set.
Petronix checked with manufacture who confirmed all working properly.
Engine compression 110 on all except nbr 7 at 105, dry, engine hot.
All grounds removed and cleaned the re-secured.

I think that is it. As you can see very frustrating.

NEED HELP PLEASE!

Thanks in advance.

Mike (Speedbump47)

09-14-2021, 03:43 PM	#1
Speedbump47 Junior Member Join Date: Sep 2021 Posts: 5	Flat spot that just won't go away G'day All I have been advised that the knowledge of the members on the site is beyond approach and can help solve anything! Recently purchased a 1948 Mercury 100 HP V8 with 6 volt positive electrics. The engine has a bad flat spot when accelerating, the PO gave up trying to solve after many tries. Looking for help to resolve as it is annoying and sometimes can be a problem. Since I've had the car the following have been changed: Plugs, wires, crab cap and rotor. Petronix ignition and coil. Rebuilt the model 59 carb following Mikes carbs on Youtube. New battery. Actions and observations: Distributor brake connected and disconnected - no difference either configuration. Intake and cylinder head bolts retorqued, no vacuum leaks detected. Vacuum gauge reads steady 11psi, never changes despite fuel/ignition changes. Swings to zero back to about 18-20 when flipping accelerator then back to 11. Mixture screw can be in all to way or out all the way but no difference to vacuum reading or engine idle. Ignition timing set. Petronix checked with manufacture who confirmed all working properly. Engine compression 110 on all except nbr 7 at 105, dry, engine hot. All grounds removed and cleaned the re-secured. I think that is it. As you can see very frustrating. NEED HELP PLEASE! Thanks in advance. Mike (Speedbump47)