Hard Starting with Warm Engine

[delaware39]

Finally got around to installing 1/2" phenolic spacer under the carburetor. I found out the hard way that Plymouth intake manifolds have different bolt spacings. I ordered the phenolic spacer based on a spare manifold, which has a center-to center stud spacing of 2 11/16". Turns out that the one on the car is 2 15/16". The man who sold it was kind enough to make me a new one for only $3.00 more. His eBay name is 68rrman, real name is Ben. It does seem to help, but the weather hasn't been extremely hot lately (for a Delaware July). I raised the float level back up and that gave me a little more low RPM response. I will know more as I get to drive more. Thanks for all of the suggestions.

[Pete]

Thanks, Pat. I got it to accompany my 1938 Dodge Brothers pickup to use for touring. My club and various groups have some great tours planned for this summer in the Vermont/New Hampshire area. I wanted something big, reliable, original, and Mopar. It's a pleasure to drive. It cruises well at 50 - 55 mph on decent roads. I just got it out of winter storage last weekend. We're building a heated garage this summer, so I'll be able to get work done on it during the cold months instead of just planning work.

The wipers are the original vacuum. I had both motors rebuilt. They park to the outside if they are operating correctly.

Pete

[delaware39]

Got it. Thank you. Your P8 is beautiful. I will be doing a lot of work on mine over the summer. I hope it comes out as nice. I noticed that your wipers point out; on mine they point in. Do you know which is correct? Mine are electric "mighty wipers." Like most things, they were on the car when I bought it.

[Pete]

Hi Pat,
I got your email. No, the phenolic spacer does not have the cut-outs, but it does not need them. If you look at the carb base and the intake manifold flange, they do not have cut-outs. As long as you are using the gasket with the cut-outs you'll be fine, as it will work just like a gasket with cut-outs between the carb and manifold with no spacer. Those little cut-outs only need the thickness of the gasket to work. I use two gaskets: one between the carb and spacer, and one between the spacer and manifold to make sure I had a good seal with no vacuum leaks.
I'm not sure about the thickness of the spacer. I used 1/4" and it worked for me. The carb probably could use a bit of heat while running, it only because you could get carburetor icing if it was very humid. It's likely a bit of a trial and error thing. It you use a 1/4" and still have fuel boiling out of the fuel bowl after a hot soak, try a thicker spacer. They are not that expensive, and getting it right can reduce a great deal of frustration.
Pete

[delaware39]

My 39 actually has an 54 engine and a Stromberg Carburetor. I had to replace the manifolds and have no idea what year the replacements are. They fit. According to NAPA, the carb to manifold gasket is the same for both years (and those in between). Did the phenolic spacer you bought have the four little cut-outs? If not, did you notice any difference in performance? One last question: you bought a 1/4". Do you think a 1/2" would be better? I have plenty of clearance under the hood.
Thanks for the tips.

[Pete]

Glad to help. Search ebay for:

2 Bolt Phenolic Riser Carter Holley Autolite Carburetor Intake Manifold Spacer

Seller is: 68rrman

I communicated with him to make sure I was ordering the correct spacer for my 1939 Plymouth. I got the 1/4 inch think spacer. Apparently he manufactures these and they are available in various thicknesses. Note that I had to install longer carb to intake manifold studs.

[delaware39]

Thanks for the tips. There are no pure gas stations in Delaware; the nearest is about 25 miles away in Pennsylvania. It was 100 octane aircraft fuel. The spacer sounds much more practical. It needs the fuel pump heat shield, too. I will try both.

[Pete]

Are you running fuel with ethanol? If so, and if possible, try running a few tank fulls on non-ethanol "real" gas. I had this same issue. Ethanol is more volatile than gas and boils at a lower temperature. In my case after a heat soak it boiled out of the carb fuel bowl and into the intake manifold. This resulted in longer cranking times. Pure gas did not boil out like that. For a long term solution I installed a phenolic spacer between the carb and intake manifold. Problem solved.

To find locations that sell pure gas go here:

http://www.pure-gas.org/

I found the phenolic spacer on ebay.

[32cabrio]

Try replacing the condenser before you get into the carb.
The hot start problem is typical of coil/condenser failures.
Also, plan on buying more than one condenser as the new ones,
made off shore, seem to have a high failure rate right out of the box.

[delaware39]

Never thought of the coil. I put a new (modern, on NOS) on about a year ago. I will check it out. I do have the float lower than specs, but I can lower it a bit more. I think I will set the lever on the starter's push rod to open up the throttle a lot more. Thanks.

[TodFitch]

How warm on the warm starts?

One of the failure modes of a coil is to work when cold and then become weak when warm. You might want to check that your spark is good and hot when the engine compartment is warm.

A fairly common issue on hot restarts is percolation of gas in a hot carburetor which results in a flooded situation. Some advocate setting your carburetor float a bit lower than the manual calls for to allow for expansion of gas in the bowl during a hot soak condition. If you do have this issue then holding the accelerator wide open (but don't pump it) will help clear the rich mixture.

There are other things that could cause a hot start issue, but those are the first two I'd look at.

[delaware39]

My 39 has a 54 engine with a Stromberg carburetor and electric choke. It starts immediately when cold and runs fine at all temperatures and speeds. After it sits for a while after running, I have to crank it more than I think is normal. I could use some tips as to how to properly start the thing when the engine is warm. Do I step on the gas once, not touch the pedal at all, whatever. There is a lever attached to the starter pedal that opens up the throttle a little. Is there a perfect place to set to open up the throttle just the right amount? Any thoughts or similar experiences?