‘40 starting to stumble a bit………

[mike42]

I’ve had the new carb on my ‘40 for a little over a month and a half and it’s been running great. All of a sudden it’s started to stumble and acts like it’s not getting enough fuel “I think”.

I have an electric pump and fuel regulator. I took out the standard pump and only going with electric.

Could it be the carb ?

I have a coil from Skip Haney that’s about 8 years old. How long do those last ?

Thx……Mike

[rockfla]

Mike


I "completely understand trying to do thing on you own, trying to save money and such. I spent 45 years of my life watching my Dad struggle with our 37 Station Wagon and pretty much the same "issues" you are having MINUS the electric fuel pump!!!! MY Final $ .02.........Take your distributor and send it to Michael at Third Gen and have him go through it, and install a "good" and "known"set of points, set the points, the dwell and your vacuum advance AND be "DONE" with it, THEN re-install your "skip" coil. Ditch that electric fuel pump and send your pump to either Mike OR CharlieNY and have THEM rebuild your fuel pump. LAST Get you a "GOOD QUALITY" condenser and you are done. I have the above posted 39 Mercury with plenty of miles on her. I "DID" ALL of the above, NOW "IF" she has run in the last 5 or so days, I hit the switch and within two turns of the starterd, she is running.....EVERYTIME!!! IF she sits for a week or more, it takes about 3 times of about 5 to 6 seconds each for the pump to pick prime back up and she is RUNNING!!!! I "TRY" to drive it at least once a week BUT for sure 3 to 4 times a month for a good little run and keep the battery fresh!!! DO IT right, AS Henry built it from the above people and I promise you, You will not be sorry!!!!! In my entire life before NOW I have NEVER had the joy this V8 brings KNOWING we don't have a major struggle to get it ready to go somewhere, knowing I don't have to have a chase car to follow encase I break down, WONDERING IF she will start once I get there ETC ETC. I would not hesitate to drive my Merc anywhere "especially" IF she had a rebuilt engine!!!!


AND After you do ALL of the above check from the gas tank TO the carburetor and make DOUBLE sure ALL of the fuel lines are GOOD and tight at EVERY junction there WILL be NO need for an electric fuel pump!!! NOR your fuel regulator!!!!


SEE POST SEVERAL BELOW THIS ON CONDENSERS!!!!!

AND just for good measure I would send your original carburetor to CharlieNY along with the fuel pump A) It never hurts to have a "known" good back up AND B) AFTER You do ALL of the above and you find out your NEW Carb is giving problems THEN you have a known good one to install!!!!!

[mike42]

Hey Rock…….thx for the info. I’m up to my butt on working on my house property and don’t have the time right now, but I’ll look into your suggestions. It was running great for 425 miles after new brakes and carb and then all of a sudden it started this problem. There is no problem starting. Hit the button and it fires right up ! Idles great at 500 rpm. I did notice the fuel reg was only showing 1 psi though ! More later.

Thx again…..Mike

[rockfla]

Originally Posted by mike42

Hey Rock…….thx for the info. I’m up to my butt on working on my house property and don’t have the time right now, but I’ll look into your suggestions. It was running great for 425 miles after new brakes and carb and then all of a sudden it started this problem. There is no problem starting. Hit the button and it fires right up ! Idles great at 500 rpm. I did notice the fuel reg was only showing 1 psi though ! More later.

Thx again…..Mike

Could be the condenser as it gets hot??? Also who's points are you using???? There are plenty of junk points out there too. That's why I suggested Mike at Third Gen as he can run it on his Sun Machine, check ALL the important "stuff" like good points, make sure your vacuum advance is working smoothly and correctly, set the dwell properly. ALSO make sure nothing is worn beyond usefulness..Its "Jam up and Jelly tight" when he gets done with it!!!!

[mike42]

Rock ………I’ve never changed the points since when I bought it. It’s always ran smooth. I’m going to take it out in the morning to see if it’s better when cold before it heats up.

Got your email thx

Mike

[mike42]

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Mystery solved.....the fuel reg was adjusted to below 1 psi !!!! How the hell that happened I don't know, but I set it at 2.9 psi and it's back to running great again.

Thx....Mike

[Veeder]

Just out of curiosity could you describe "stumble" a bit. I've a stock v8 and runs great when I punch it a bit it will shut down like not enough fuel but then picks up at a lower rpm. If I accelerate at a modest rate all is good.

Bob

[rockfla]

Great to hear Mike, so glad you found your issue!!!! Now go enjoy ride

[rockfla]

Veeder


Could be a several issues. First do you have a "good" vacuum advance line, NO leaks. Have you had your distributor rebuilt OR know that the vacuum advance is working properly? IS the vacuum advanced set correctly?? What carburetor are you running? Is it "tight" and able to adjust the mixture screws effectively?? These two area's/questions would be My first start of investigation!!! IMO


ALSO what year flathead are we talking about???

[Veeder]

It's a 41 stock

And last winter I messed with the distributor and rebuilt the carb. This is a new issue this year so I screwed something up a bit. I've a extra distributor will pop it on as well as make sure the accelerator pump is working. I'm suspicious of the vac brake I just haven't had time to dig into it

[rockfla]

After you rebuilt your carburetor you were able to adjust it with NO issues??? Both air mixture screws worked properly??? The accelerator pump is one for the new modern gas???

[mike42]

Vee ……. When it was cold it ran okay but as it warmed up it started to stumble or buck a bit like it wasn’t getting fuel. I never thought to check the reg psi. I started it up Tuesday morning and happened to look at the reg and is was almost flat ! I loosened the nut and adjust to 2.9 prox and took it out. No more stumbling.

Rock …… I bought a new USA made carb from Dennis carpenter and didn’t touch a thing. It started right up and ran good until it started to stumble. Then I found the reg was set too low. I never touch the screws other than idle adjustments.

Thx……..Mike