As a recent convert to the joys of old truck ownership, I greatly appreciate the collective knowledge of FTE. The depth of practical advise is outstanding. So, I need a diagnosis and cure, please.

'49 F1 flattie six - original everything: carb, fuel system, and electrical. The truck starts like a champ and responds to the throttle. Got stranded 2x recently after running to temp (about 6 miles of easy pace) when I couldn't keep 'er lit while moving. At idle, everything is great - put it in gear start to move - and the engine dies. It will restart with the choke and repeat the cycle.

Steps I've taken: Cleaned the carb and installed new gaskets, cleaned the fuel bowl (there was some accumulated soft gunk here), checked the plugs and wires. Problem remains.

What I noticed: There is a 'governor' beneath the carb - spade shaped piece below the carb lower air horn. My mechanical assistant could affect the rev by moving the governor. Clearly, we couldn't have him sit under the hood while moving - I'm thinking this would have allowed a dignified drive home (rather than the sympathy tow job that it took).

What the Shop Manual Sez: Sounds like the governor does exactly that for the airflow. My problem does seem to be related to starving the air flow - the quick restarts would suggest that fuel is present. The good book has some very general instructions to replace the unit.

My question: Is this the problem? If so,what do I do? Replace the governor (with parts from where)? Remove it? Chant and offer sacrifice to the ghost of Henry?

Help me oh assembled wizards.

DW

 

The part you have pictured is for the heat riser in the manifold. It controls a flap inside the manifold to direct heat to the intake manifold. This is suppose to help in cold weather. Most trucks don't have them because they usually are rusted solid.

Sounds like you have a carb issue. Maybe your float isn't adjusted correctly.

BTW, where in WI are our located? I might have asked this before but don't remember. I'm in SE WI, just north of Milwaukee.

 

Howdy neighbor - I'm in Cedarburg, just a couple of stop signs from G-town!

So, if the float was an issue, wouldn't I see this before I get up to temp?

DW

 

If your float is set too low you'll have enough gas in the bowl to run at idle or low RPM but once you reach temperature the low amount of gas could be vaporizing. Just my theory.

 

Cedarburg? You'll have to stop over some time. Nice to see some one with another old truck in the neighborhood.

 

49r, send me a PM or email. I can't send one to you. Maybe because of your low post count. You can email me bobj@fatfenderedtrucks.com

 

When you put new gaskets in the carburetor, did you soak the parts in solvent? If one of the passages leading from the jet to the spray bar, or in the spray bar is plugged you will get exactly the symptoms you describe.

Can you rev the engine up with the transmission in neutral?

A long shot - you may be missing a part from your carburetor. Did you check the assembly against an exploded view when you put it together?

Another possibility: you have a massive vacuum leak between the intake and exhaust manifold caused by the bottom of the intake burning out.

 

Hey '38
No, I didn't soak the gaskets. I did check and recheck the positioning and alignment to ensure that all the various orifices were clear. The engine absolutely responds to the throttle - both in and out of gear. It appears that all the parts are present compared to the Shop Manual views and nothing burned through or burned out.

I'm still thinking that I'm fighting an issue with the heat riser. If I can replicate the problem by playing with the riser when cold, I'm thinking this will show me something. If it is a the problem, is there a ready solution?

 

Is the heat riser loose? Most I have seen were rusted in position. You could be warming the intake and tranferring the heat up to the carb. I'm not an expert but that's my guess.

 

The riser doesn't appear to be loose. It certainly moves - both under idle or with manual intervention. So, if these get rusted in position, that means you don't need this work to be operational?

DW

 

I don't think mine moves at all. I haven't really looked at in years. I know the thermo spring hasn't been on it in many years. I rarely run the truck in our marvelous WI winters so I don't worry about it.

 

This may seem odd, but doubble check your timing and dwell. May have bumped the distributor or just by odd chances the points came out of whack.

Like others said... sounds very much like a vacuum leak. You plug any and all unused ports on the carb?

If the heat riser was stuck shut, you'd mostly notice the negitive effect of it under a load or wide open throttle while driving. Even so, it should still idle in gear.

If at nothing else, tie the heat riser open, that should eliminate that from the equation once engine is warmed up.

If you have to choke it every time to start it after it dies, even after its warm, tells me you got a lean condition. Idle mixture screw adjusted properly? Dang... keeps pointing me to a vacuum leak in my mind...

 

Hey Dano

Thanks for the comments. I'm with you on disabling the riser. Worst case, it gets eliminated as an issue. Can also recheck the vacuum connections. The performance at idle is actually great - doesn't stall out or seem starved in any way. Revs up and down - both at cold start and even after restarting when at temp.

DW

 

'38 didn't ask about soaking the gaskets, he asked about soaking the parts. It doesn't take much to clog those small passages in a carb or thru a jet. It's also pretty easy to mix up the little *****, or miss a small weight when reassembling a carb.

I have a Holly 1904 on my beastie. It spewed fuel all over and flooded out after a rebuild because the new needle and seat didn't play nicely together. The Power Valves (NOT the same as the accelerator pump) in them old carbs can go bad too, and those are almost impossible to find these days. Weather or not these same issues are common across all the old carbs, or just the 1904 I don't know.

When you say "original", are you talkin the fuel tank and fuel lines also? I don't know about you, but after 53 years i'm all clogged up, and prolly so is you truck's fuel system. When's the last time you cleaned or replaced the air cleaner?

One little thing I've come to find holds true quite often. if it spit sputters and dies it's generally fuel. if it just stops dead, it's generally electrical.

 

Very good advice