WA1 carbs hot starting issues

dave11

After rebuilding the carbs on my 52 Hornet and adjusting for balance with a Unisync. it now  starts and runs great.

 Except when the motor is hot, then you have to run the starter for an honest  5 seconds with the throttle open, it always starts but this put an uneeded strain on the starter motor. When it is cold it fires up immediately.

 it "appears" that the engine is flooded????any suggestions would be appreciated.

Dave Eddie

Glowplug

float level in carbs should be lowered to compensate for corn gas. Make sure the leather seal in the perculator valve is good and sping tension. Metering rods should be checked for wear too. Make sure the ground straps from engine to frame and frame to body are clean and secure. Good Luck

RichardD

Perhaps an elec. fuel pump to operate for about 4 seconds if the gas has evaporated in the bowl ?? Need a HOTTER spark ?; full voltage on starting to bypass a ballast if you have one.?

PAULARGETYPE

DO YOU HAVE HEAT PLATES INSTALLED UNDER THE CARBS YOU ALSO SHOULD HAVE 8 GASKETS 4 ABOVE THE HEAT SHIELD AND 4 BELOW IT WITH THIS GAS WE ARE USING IT IS A MUST !!

Frankvintagefullflowcom

How does it behave when it does start? If flooded, it should emit black smoke and run roughly 'til it clears the excess fuel. If not, you're probably looking at some other cause.

Did this condition creep up on you or did it start abruptly? What prompted you to do the carb rebuilds to begin with? I chased what appeared to be a similar fuel issue for some time without relief before it finally became so bad that I looked elsewhere, i.e., ignition. Changing the new NAPA Chinese coil back to the original Autolite coil cured it immediately.

Just a thought.

F

russmaas

I have had these issues with a lot of my cars when they hit running tempatures . Classic vapor lock with todays fuels. I am considering running an inline fuel pump also. If I run them from garage to garage for a few minutes they will start with no problem but if go for a drive and shut it down for 5 minutes the fuel is burned away and needs to be pump up again.

dave11

The carb rebuild was done a while back as the car had sat for a Long time. Once started it runs fine...if I look into the carb throat when hot and activate the throttle the accelerator pump squirts fuel,..so I don't think it is a lack of gas in the carb bowl.

If the car sits for a month or so and the fuel evaporates in the carb, then it will take a while to start, lack of fuel, in that case an electric pump would help.

I will have a look at insulators under the carb and revisit the leather seal and adjustment to the anti perculator valves.

On the bright side it's been perfect weather lately for chasing this issues 36 degrees  yesterday !

Dave

RichardD

Fel-Pro 60269; $2.99 @ O'Reillys. Would need 8 plus new studs. But, might have carburetor ice---lol.

dave11

RichardD said:

Fel-Pro 60269; $2.99 @ O'Reillys. Would need 8 plus new studs. But, might have carburetor ice---lol.

Success,.....I replaced the carb to intake mainifold insulators as suggested, although I could only install 3 below the heat shields  and 3 above, as the carb mounting studs are not long enough. The OEM Hudson service manual "does specify" 8 insulators. So I happened to have a few original insulators, which when I measured for thickness are about .070"  where the replacement Felpro ones are .125" thick.

Also I revisited the instructions for setting up the anti perculator valves on the carbs,...mine where not openning at all. 

After adjusting with the throttle plate opening to .020" and allowing .005" gap at the perculator valve, the engine fires up immediately even after a good long run.

Dave Eddie

Glowplug

Great result dave11, thanks for sharing the outcome!

Jon B

Glad you worked through your issues, Dave11.  I did the "8 spacers plus heat shield" thing many years ago in my '37, and I have never had a vapor lock problem since, even when idling in traffic on the hottest days.  I DID buy some longer studs, however.  They're so tall that it makes it difficult to get the nuts on; I have to actually hold the carb up in the air in order for the nuts to clear the top of the studs, when bolting the carb down.  But that's a minor thing, really.

Frankvintagefullflowcom

Just an FYI if you do use longer studs to overcome the thickness issue, be sure the stud doesn't contact the underside of the iron base casting upper flange. If that happens, you get a "feel" as though the carb is tightening up but it's actually the stud coming up against the upper flange. The result is a gap between the base and manifold......or worse yet, a broken base casting "ear".

I bought ta Jet that had been "worked-on" by the previous owner who just couldn't get it to run right and found a substantial gap under the carb. I don't know why it even ran. In this case, it was a lack of gasket-stack thickness with original studs, but the effect would be the same. 

F

iceblade10

Regarding the Fel-Pro 60269 gaskets - do I need 8 per carb, for a total of 16?  Or 4 per carb, for a total of 8?  I understand that some people use 8 gaskets per side, but they might be thinner than the Fel-Pro 60269 gaskets...?

Also, I'm wondering how much longer the studs should be.  I guess the only way to know for sure is to get all the gaskets, and mock things up...

Jon B

I can only speak for the prehistoric, pre-war carbs, but I use -- starting from the manifold and working up --  4 gaskets, a metal heat shield, then four more gaskets, then the carburetor. 

So yes, you will need 8 per carb. 

I'm pretty sure this was not "from the factory" in 1937, so to speak.  In fact, I had such a high gasket stack that it was necessary to replace the threaded studs on my intake manifold (which held the carb) with longer ones, to accommodate the extra gasket thickness.  And then the studs were so high that their tops almost hit an overhanging part of the carburetor, so that there wasn't adequate clearance to slip the nuts on!  I actually had to raise the carb up a bit (after positioning it on the 4 studs) and "start" all four nuts.  Once they had been screwed down a bit,  the carb would sit down against the manifold again, and I could tighten the nuts.

Still, it was worth the effort because I have never had a case of vapor lock in my '37, even on the hottest days.

SuperDave

Be careful with a taller carb on a stepdown with 2BBL. The air cleaner wing nut on top may dent the hood. Don't ask me how I found that out.