Potential causes for warm start difficulty
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules
-
Topic author - Posts: 398
- Joined: Sun Jan 13, 2019 6:20 pm
- First Name: Neal
- Last Name: Willford
- * REQUIRED* Type and Year of Model Ts owned: 1911 Touring, 1915 Runabout
- Location: Kansas
- MTFCA Number: 50256
- Contact:
Potential causes for warm start difficulty
This week I gave my son and his fiancée their first ride in the 1911 touring that I just finished restoring. The temperature was in the upper 50s and it started and ran fine. After we got back from our drive, I shut it off so that they could take some pictures of it and to put the top down before putting it into the garage.
Normally the car starts on the first or second pull when warm on battery or magneto without priming. For some reason, this time it wouldn't start or even sputter after numerous 1/4 turn pulls. I did use the choke it once or twice after it wouldn't start after a bunch of pulls, but that didn't help. After that I decided to clear the cylinders of any excess gas by closing the mixture needle, opening the throttle, and pulling it over four 1/4 turns. After doing that and opening the mixture needle back up, the car started right up. It easily started after that.
I have experienced this once before on our 15 runabout and had to do the same thing to get it started. The 11 has a Holley H1 and the 15 a Holley G. Any thoughts on what might have caused this issue?
Thanks,
Neal
Normally the car starts on the first or second pull when warm on battery or magneto without priming. For some reason, this time it wouldn't start or even sputter after numerous 1/4 turn pulls. I did use the choke it once or twice after it wouldn't start after a bunch of pulls, but that didn't help. After that I decided to clear the cylinders of any excess gas by closing the mixture needle, opening the throttle, and pulling it over four 1/4 turns. After doing that and opening the mixture needle back up, the car started right up. It easily started after that.
I have experienced this once before on our 15 runabout and had to do the same thing to get it started. The 11 has a Holley H1 and the 15 a Holley G. Any thoughts on what might have caused this issue?
Thanks,
Neal
-
- Posts: 3419
- Joined: Sun Jan 06, 2019 10:53 am
- First Name: Tim
- Last Name: Wrenn
- * REQUIRED* Type and Year of Model Ts owned: '13 Touring, '26 "Overlap" Fordor
- Location: Ohio
- MTFCA Number: 30701
- MTFCI Number: 24033
- Board Member Since: 2019
Re: Potential causes for warm start difficulty
Some form of a vapor lock maybe?
My '13 started that little stunt the first year I had her, after stopping her to gas up, for all the longer it would take at the pump, she'd hardly start afterward without yanking my guts out, choking it, adding "extra" fuel on the lever. After that year, it only happened once in the last 5 years. Go figure.
My '13 started that little stunt the first year I had her, after stopping her to gas up, for all the longer it would take at the pump, she'd hardly start afterward without yanking my guts out, choking it, adding "extra" fuel on the lever. After that year, it only happened once in the last 5 years. Go figure.
-
- Posts: 6443
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- MTFCA Number: 51486
- Board Member Since: 2021
Re: Potential causes for warm start difficulty
It sounds like a mixture problem. Normally, an updraft carburetor isn't subject to hot flooding, but I suppose it can happen. Since choking did not get good results, and clearing the engine did, It appears that it was flooded. Underhood heat imediately after stopping the engine after a run could result in fuel boiling in the carburetor, which could lead to flooding. I would check to be sure the choke is opening fully. It could be something unrelated to fuel mixture, like an intermittent ignition switch. When starting a hot engine, opening the throttle about 1/4 open may be helpful. If you start on magneto, it's possible the magneto output is a little less when hot, due to the magneto air gap being larger due to expansion of parts.
-
- Posts: 589
- Joined: Sun Mar 24, 2019 8:22 pm
- First Name: John
- Last Name: Michaelree
- * REQUIRED* Type and Year of Model Ts owned: 1926 Touring 1927 Tudor
- Location: st louis
- MTFCA Number: 50389
- Board Member Since: 2010
Re: Potential causes for warm start difficulty
Yes, it sounds like your carb is running too rich for a warm engine. Double check your mixture needle adjustment. When parked, does your carb drip gas? If the float needle does not seat tight, over time it can over fill the bowl preventing one pull and free starts on a warm engine that we all love.
Last edited by JohnM on Thu Nov 24, 2022 11:40 am, edited 2 times in total.
-
Topic author - Posts: 398
- Joined: Sun Jan 13, 2019 6:20 pm
- First Name: Neal
- Last Name: Willford
- * REQUIRED* Type and Year of Model Ts owned: 1911 Touring, 1915 Runabout
- Location: Kansas
- MTFCA Number: 50256
- Contact:
Re: Potential causes for warm start difficulty
It could have been a bit rich, although I leaned it out initially after richening it 1/4 turn to initially start it. No gas was dripping. It just seems odd that it would be running fine and after being shut off for 5 minutes at the most, not being able to start at all. Certainly clearing out the cylinders seemed to make a difference for starting it at least. I should also say that at the moment I don't have the hot air pipe on, but I haven't either for most of the time I've been running it recently. It was low humidity and am using "winter blend" gas.
The ignition is also fine. Rebuilt coils, clean and 0.030 gapped Champion X plugs.
Vapor lock could be a possibility. Perhaps choking it cleared it out, and then clearing the cylinders cleared out the excess fuel from that.
Last edited by NealW on Thu Nov 24, 2022 10:33 am, edited 1 time in total.
-
- Posts: 6443
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- MTFCA Number: 51486
- Board Member Since: 2021
Re: Potential causes for warm start difficulty
"Winter blend" is intended to vaporize more readily, so it might tend to cause hot flooding under some conditions. Once warmed up, leaning out the mixture a little more than normal may get better results, especially on mild winter days. When starting a hot engine after a short shut down period, it's often best to assume it needs no choking at all. If a couple of pulls get no result, or a just a kick or two, a single pull with the choke on would probably be sufficient. Of course, all cars are different, and weather conditions and conditions of use have to be accounted for. Setting the plug gap at .028 may be helpful.
-
- Posts: 589
- Joined: Sun Mar 24, 2019 8:22 pm
- First Name: John
- Last Name: Michaelree
- * REQUIRED* Type and Year of Model Ts owned: 1926 Touring 1927 Tudor
- Location: st louis
- MTFCA Number: 50389
- Board Member Since: 2010
Re: Potential causes for warm start difficulty
I have a 26 with an NH carb. After sitting warm for fifteen or twenty minutes then starting, it kicks and sputters with too much gas. If I shut the gas off when I stop for more than ten or so minutes, later it will start very easily on one pull. BTW I don't have a hot air pipe.
-
- Posts: 4094
- Joined: Tue Jan 08, 2019 1:39 pm
- First Name: Norman
- Last Name: Kling
- Location: Alpine California
Re: Potential causes for warm start difficulty
I would suspect that you might have turned off the switch before the engine slowed down. Try pushing all the way up on throttle and spark first before you turn off when you stop the engine. That way it burns out the gas in the cylinders. If it is running too fast, you will draw in a gulp of gas before it completely stops turning which could flood the cylinders, especially if running rich.
Norm
Norm
-
Topic author - Posts: 398
- Joined: Sun Jan 13, 2019 6:20 pm
- First Name: Neal
- Last Name: Willford
- * REQUIRED* Type and Year of Model Ts owned: 1911 Touring, 1915 Runabout
- Location: Kansas
- MTFCA Number: 50256
- Contact:
Re: Potential causes for warm start difficulty
I did not move the throttle to slow idle before shutting it off, so that could have been a factor.Norman Kling wrote: ↑Thu Nov 24, 2022 11:42 amI would suspect that you might have turned off the switch before the engine slowed down.
-
- Posts: 366
- Joined: Sun Jan 06, 2019 2:25 pm
- First Name: Dick
- Last Name: Fischer
- * REQUIRED* Type and Year of Model Ts owned: 1912 Touring
- Location: Arroyo Grande, CA
Re: Potential causes for warm start difficulty
Neal, People have already posted who have far more experience with model T's than I do. But here is my experience with a 1970's automobile.
I was having a problem where the car was usually flooded after a short rest, but then started up just fine after sitting overnight. What I eventually found was a leaking carburetor where the float bowl emptied itself within a few minutes after shutting down. The only way I could start it after a brief shutdown was to begin cranking with the gas pedal pressed to the floor to clear the flood.
My car was a downdraft, so that made matters worse. But with a modern electric starter I was able to clear the flood readily once I understood what was going on. Yours being an updraft wouldn't be quite so bad, but could still have a bunch of raw fuel laying in the venturi as you begin hand cranking.
My fix was to overhaul the caburetor.
I was having a problem where the car was usually flooded after a short rest, but then started up just fine after sitting overnight. What I eventually found was a leaking carburetor where the float bowl emptied itself within a few minutes after shutting down. The only way I could start it after a brief shutdown was to begin cranking with the gas pedal pressed to the floor to clear the flood.
My car was a downdraft, so that made matters worse. But with a modern electric starter I was able to clear the flood readily once I understood what was going on. Yours being an updraft wouldn't be quite so bad, but could still have a bunch of raw fuel laying in the venturi as you begin hand cranking.
My fix was to overhaul the caburetor.
-
- Posts: 6443
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- MTFCA Number: 51486
- Board Member Since: 2021
Re: Potential causes for warm start difficulty
Downdraft carburetors can really flood an engine. One that leaks gasoline after shutting off will flood the engine, then if the vehicle sits overnight, the carburetor will be dry and may cause hard starting for lack of fuel. Another way downdraft carburetors can cause trouble is after a hot shutdown, gasoline can boil in the carburetor and flood the engine. This often occurs in hot weather. Modern gasoline seems to be more prone to doing this. Air conditioned V8 cars were bad about flooding after a short stop in hot weather. The solution was to hold the gas pedal to the floor while cranking the engine, but some people preferred to pump the gas pedal and run the battery down.
-
- Posts: 3923
- Joined: Sun Jan 06, 2019 8:00 pm
- First Name: John
- Last Name: Kuehn
- * REQUIRED* Type and Year of Model Ts owned: 19 Roadster, 21 Touring, 24 Coupe
- Location: Texas
- MTFCA Number: 28924
Re: Potential causes for warm start difficulty
I’ve found that if my T won’t start it’s usually something to do with to rich of a fuel adjustment after it’s warmed up. But as you all know it’s finding the sweet spot when adjusting the carb. One of my cars has a tendency to flood if it’s just past the sweet spot adjustment while the other car is just before the sweet spot adjustment! (lean)!
I’ve learned to idle down before I cut the switch off and that usually works for me.
I think that if we drive our T’s pretty often the problem isn’t as bad or not much at all. It seems that way for me.
Each car has a mind of its own I guess!
I’ve learned to idle down before I cut the switch off and that usually works for me.
I think that if we drive our T’s pretty often the problem isn’t as bad or not much at all. It seems that way for me.
Each car has a mind of its own I guess!
-
- Posts: 6443
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- MTFCA Number: 51486
- Board Member Since: 2021
Re: Potential causes for warm start difficulty
All Model Ts are alike, except they're all different.
-
- Posts: 5256
- Joined: Sun Jan 06, 2019 7:21 pm
- First Name: Allan
- Last Name: Bennett
- * REQUIRED* Type and Year of Model Ts owned: 1912 van, 1917 shooting brake, 1929 roadster buckboard, 1924 tourer, 1925 barn find buckboard, 1925 D &F wide body roadster, 1927LHD Tudor sedan.
- Location: Gawler, Australia
Re: Potential causes for warm start difficulty
Both the Holley H1 and the model G are plain old Ford issue carburetors, so down/updraft issues are irrelevant. The Holley H1 on my 1912 van is sensitive to the float level. Once I got it right, i I have had no problems since.
Allan from down under.
Allan from down under.
-
- Posts: 1033
- Joined: Mon Jan 07, 2019 5:32 am
- First Name: Leo
- Last Name: van Stirum
- * REQUIRED* Type and Year of Model Ts owned: 1923 Huckster, '66 CJ5 daily driver
- Location: Netherlands
- Board Member Since: 2016
Re: Potential causes for warm start difficulty
You nailed it, I have several old cars from other owners that i do the maintenance on and a T and a '66 CJ5 and most of them have this trait in one or other form.NealW wrote: ↑Thu Nov 24, 2022 12:05 pmI did not move the throttle to slow idle before shutting it off, so that could have been a factor.Norman Kling wrote: ↑Thu Nov 24, 2022 11:42 amI would suspect that you might have turned off the switch before the engine slowed down.
I think it has to do with carburetor development, the older the carb design the more prone to this fenomenon (and other nasty habits like vapour lock), the older the car, the richer they tend to run especially at idle.
At cold start they like to be really "wet" but on a hot start that is generaly a bit too much and leads to flooding and hard starting
When in trouble, do not fear, blame the second engineer !
Leo van Stirum, Netherlands
'23 Huckster, '66 CJ5 daily driver
Leo van Stirum, Netherlands
'23 Huckster, '66 CJ5 daily driver
-
- Posts: 229
- Joined: Tue Aug 13, 2019 5:43 am
- First Name: Robert
- Last Name: Thompson
- * REQUIRED* Type and Year of Model Ts owned: 1915 touring 1926 roadster
- Location: virginia
Re: Potential causes for warm start difficulty
My 1915 runs and starts GREAT hot or cold unless there are a number of people watching me crank. The more people, the more I crank. bobt
-
- Posts: 61
- Joined: Mon Jan 21, 2019 6:22 pm
- First Name: Nick
- Last Name: Miller
- * REQUIRED* Type and Year of Model Ts owned: 1926 touring
- Location: NRedington Bch, FL
- MTFCA Number: 31031
- MTFCI Number: 18935
Re: Potential causes for warm start difficulty
You might try using another carburetor, if available, and see if it has the same issues. Float level, leaking valves or air leaks may all play part in the gas issues. All seem to have a specific or different way to deal.
Good luck. Try dealing with another club member to borrow a carb, if you don' have one.
Good luck. Try dealing with another club member to borrow a carb, if you don' have one.
-
- Posts: 227
- Joined: Sun Jan 06, 2019 1:26 pm
- First Name: Thomas
- Last Name: Loftfield
- * REQUIRED* Type and Year of Model Ts owned: 1912 Touring, 1912 Express Pick-up
- Location: Brevard, NC, USA
- MTFCA Number: 49876
- MTFCI Number: 24725
Re: Potential causes for warm start difficulty
Exactly the same problem encountered on a 1910 Buick Model 10 with a Schebler Model D carburetor. After driving myself crazy fiddling with the carburetor, double checking the magneto, and wondering if maybe incorrect tire pressure was at fault (that desperate), the trouble was finally found to be vapor lock in the fuel line. Re-routing the fuel line completely cured the problem. On my Model T's I route the fuel line under the exhaust for the same reason, have never had a vapor lock on the T's.
-
- Posts: 6443
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- MTFCA Number: 51486
- Board Member Since: 2021
Re: Potential causes for warm start difficulty
Fuel lines need to be kept away from heat. Any upward arching bends that could trap bubbles should be avoided. Even small dents or any other added restriction can cause fuel delivery problems, especially in hot weather or in high alitude operation. Always check that the gas cap vent is clear if fuel delivery problems are encountered. Carburetor bowl vents must be kept clear, also.