hard to start when warm

[Tom VanMeeteren]

My 1911 always starts on the third pull of the crank when it is cold. However when it has been running down the road for a while, it takes about 12 - 15 pulls on the crank to start it. I have tried letting the carb (NH) run out of gas, choking it with two or three pulls and letting it set for a minute or so, no choke, advanced throttle, mid rpm throttle, low throttle. Really is frustrating, but when it starts it runs great again. ???????????????? any ideas short of giving it a sniff of ether?

[rickd]

Tom, do you have a spare carb you could install and see if that makes any difference?

[speedytinc]

Sounds like its flooding from a drippy needle/seat?
If it sits with the gas on, does it drip any?

[Norman Kling]

Do not choke it when warm. If the needle was correctly adjusted before you turned it off it should start right up with one quarter turn of the crank. Just pull up on it and it should start. If fuel drips out of the carburetor you might have a bad float or float valve.
Norm

[Kaiser]

In general most cars from the T era like to be really 'wet' with gasoline when starting cold, when warm though, not so much, you might even have to lean the mixture by turning the needle a quarter turn in when starting warm.
When your car starts real easy when cold, it is a sign that it is on the rich side for starting when warm.
Hope this helps.

[Loftfield]

Another small idea: when you shut off the engine after a run, try opening the throttle as the engine dies (ignition off). My experience has been that the car will start easily even when warm, no choke at all, one or two pulls on the crank handle. Beyond that benefit, the car more often than not gives me a free start when turning ignition to battery for starting.

[George House]

Mine is like that too Tom. So I keep a bottle hydraulic Jack with a homemade ‘cradle’ that fits on top, a light 3 leg Jack stand and short 4X4 in the turtledeck. When warm and won’t start, I simply and quickly deploy these items (4x4 in front of front tire), place it in gear and crank it to start. That way you have 2 ‘flywheels’ (1 rear wheel) to gain momentum.. YMMV

[Colin Mavins]

When hot my 1912 will free start almost every time , I do run it on an NH carb. With the original holly carb not so much.

[George House]

Dontcha love it when an OP asks a very relevant question seeking advice on overcoming a Model T issue and the one-up-man-ship kicks in when a Forum Friend states something to the effect ‘We’ll I don’t have that problem. My T is consistently responsive’… So I appreciate tdump’s motto:
“If you can’t help ‘em, don’t hurt ‘em”

[Jerry VanOoteghem]

Dontcha love it when an OP asks a very relevant question seeking advice on overcoming a Model T issue and the one-up-man-ship kicks in when a Forum Friend states something to the effect ‘We’ll I don’t have that problem. My T is consistently responsive’…

So true

[TWrenn]

Wonder if it's a case of vapor locking? I had that happen when I first had my '13. Every time I gassed up at a gas station I had to wait 5 minutes or so for it to cool down a bit before it would start. Moved the fuel line away from "things" a wee bit and haven't happened since. Just a thought. Can be so many variations.

[TXGOAT2]

I believe that in most cases, "my car doesn't do that" is intended to make the point that the issue under discussion is not normal, and such statements often include what an owner did to remedy a similar problem.

[JTT3]

Tim I think you’re on to something, a friend had a similar problem as Colin, he moved the fuel line closer to the rail & put a sort of S curve coming off the rail an into the elbow fitting into the carb. Presto Change’O no more problem. He later changed the fitting on the fuel line so he could make a 90 off the rail side straight into the carb supply port. The change was purely aesthetics because the original change still was working. I should mention that he used steel fuel line ( he’s a design engineer, go figure) because it absorbs heat at a lower rate than copper. I know that copper shouldn’t be used but the reality is a lot of T owners do.

Best John

[troutjohn]

I had the same problem on my 12 T but with Holly G Carburator. It started cold easily, ran well, but hard to start when warm / hot. I tried several things including insulating the fuel line. The solution was adjusting the float level in the Carburator. The level was too high in the bowl. I'm not sure if this applies to your NH but just an idea.

John

[vech]

I have a '15 touring car, with a Stromburg OF carb. All my steel fuel lines from the on tank bowl forward are sleeved with Design Engineering Heat Shield Sleeve part #010403 available from O'Reilly auto parts. This seems to do the trick, keeping the excessive heat away from the lines.
I also have a second fuel shut off ball valve installed in the inlet of the OF carb. 95% of the time, my hand start only car will give me no trouble starting when hot. In temps above 90 degrees however, sometimes it will refuse to start.
I have always religiously shut the ball valve off at the carb, when shutting the engine down no matter what the ambient temperature is. After experiencing severe vapor lock on my Model A in the summer heat ( when I stopped at a red light, it would quit, and I would shut the valve off at the tank, and pull the bowl to discover it was bone dry) I began to think about the hard start problem of the '15 T model.
Recently, just as an experiment, when I shut the T down after a 30 mile drive, I did NOT shut the fuel off to the carb. After a few minutes, I heard the noise of bubbling coming from the under seat tank for a short while!
By the way, I NEVER run ethanol fuel, only real gasoline. But, if you do some research concerning the today's oxygenated fuel versus what it was 50 years ago, you will find that the boiling point of todays fuels are much lower than they were long in the past.
Now, my theory is:
Obviously, the gas was boiling in the carb after shut down. But shutting off the ball valve at the carb, gave the boiling vapor no place to go, except into the throat and intake manifold, flooding the engine with excessive gas. By leaving the valve open, it relieved the pressure in the carb, pushing the gas and vapor back up the line. In few moments, I restarted the car, with only two pulls of the crank, with no frustrating excessive energy required in this hot weather.
Keep in mind this is just my theory... Everyone can tell me why I am dead wrong......

[Norman Kling]

Vapor lock is caused by air caught in the line which just compresses and will not allow the fuel to flow to the carburetor. To prevent vapor lock the lowest point in the fuel line should have line going uphill to both ends so the gas will go to the bottom and push the vapor up either back into the tank or into the carburetor.
Norm

[Daisy Mae]

Gas with ethanol combined with heat don't mix. The ethanol lowers the boiling point and further exacerbates vapor lock.
In all the modern vehicles I've restored, I've replaced mechanical pumps with electric...gasahol under vacuum (tank to pump) boils even that much lower...pressurizing the line eliminates the issue.
In the T, the fuel line in such proximity to the exhaust presents risk for vapor lock. The line on my 14 was laying right on top!!
I redid my line with more clearance above/away from the exhaust, clamped it inside my frame rails, and sleeved it with a heat reflecting tube.
In my Model A I only run it with non alcohol gas, 1) to help mitigate vapor lock, & 2) to help eliminate water absorption in my humid climate. Expensive yes, but I don't drive her much beyond once a week errand run.

What makes me scratch my head is, gasahol was common in the T's entire life....so you'd think this system was just as susceptible then as it is now....yet I don't see much in the way of period fixes.

[Tom VanMeeteren]

I don't run alcohol gas in any of my old vehicles or chainsaws. I have been shutting off the gas near the carb and letting the engine run until the carb is out of gas, so there is no boiling of gas that enters the intake manifold. My theory was that when I turned the gas back on and filled the bowl, it would belike a cold start. That is when it won't start until you crank it a bunch. There is no dripping of gas from the carb when it sits with the gas on and not running.

[speedytinc]

The line may be developing boil bubbles.
Make sure your line has no high spots for these bubbles to capture.
You can test by turning on the fuel before you start & open the bowl drain, confirming fuel filling the bowl.