LarrBeard
12-04-2015, 12:46 PM
Well, it has been a sort of satisfying couple of days. We let the truck sit for a day so the pan gasket set up, then went back to trying to get it to run.
Our reworked battery cables and grounding arrangement works very well. The engine turns over much faster and as we measured battery voltages, under heavy cranking the battery only drops to 5 volts. Most of that is an internal loss in the battery, so there is plenty of “juice” to turn over the engine. Just for drill we powered the ignition off an external six-volt lantern battery, but that turned out to be overkill.
OK, now let’s start it up.
Pull the choke, the linkages on the carburetor open the throttle so there is no need to stand on the accelerator pedal. Hit the foot starter. The new, tight engine turns over nicely and on about the fifth or sixth cylinder, she fires! She runs and purrs as contentedly as an F-head 4-cylinder ever does.
NICE!
Uh-oh. About a minute or so into the run, the tone changes, she’s starting to stumble a bit. There is a gargle from the carb throat and liquid fuel is coming out of the idle ports. Then, she stalls. Ports that should only have a bit of vaporized fuel are being flooded with liquid fuel. Not a good condition.
As she ran we looked at inlet fuel pressure, 3-pounds after the new pressure regulator, right at what we were told was the carburetor inlet spec. At this point, we’re going to call the guy who rebuilt the carburetor, but everything is pointing to a problem with the float and inlet needle valve in the carburetor. We’re reluctant to tear into a newly rebuilt, $300 carb – it should be right???
If we get this solved, things do look good. The fact that the engine runs so smoothly, even if only for a couple of minutes, relieves fears that something was wrong in the engine (don’t even think of a timing gear being a couple of teeth off…). With the new cabling, our worries about the starter are gone. We’ve gotta get some breaks now!
Oh – here is a picture of the new bumper.
Our reworked battery cables and grounding arrangement works very well. The engine turns over much faster and as we measured battery voltages, under heavy cranking the battery only drops to 5 volts. Most of that is an internal loss in the battery, so there is plenty of “juice” to turn over the engine. Just for drill we powered the ignition off an external six-volt lantern battery, but that turned out to be overkill.
OK, now let’s start it up.
Pull the choke, the linkages on the carburetor open the throttle so there is no need to stand on the accelerator pedal. Hit the foot starter. The new, tight engine turns over nicely and on about the fifth or sixth cylinder, she fires! She runs and purrs as contentedly as an F-head 4-cylinder ever does.
NICE!
Uh-oh. About a minute or so into the run, the tone changes, she’s starting to stumble a bit. There is a gargle from the carb throat and liquid fuel is coming out of the idle ports. Then, she stalls. Ports that should only have a bit of vaporized fuel are being flooded with liquid fuel. Not a good condition.
As she ran we looked at inlet fuel pressure, 3-pounds after the new pressure regulator, right at what we were told was the carburetor inlet spec. At this point, we’re going to call the guy who rebuilt the carburetor, but everything is pointing to a problem with the float and inlet needle valve in the carburetor. We’re reluctant to tear into a newly rebuilt, $300 carb – it should be right???
If we get this solved, things do look good. The fact that the engine runs so smoothly, even if only for a couple of minutes, relieves fears that something was wrong in the engine (don’t even think of a timing gear being a couple of teeth off…). With the new cabling, our worries about the starter are gone. We’ve gotta get some breaks now!
Oh – here is a picture of the new bumper.