Fast idle due to overheating (possibly)
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- Minor Friendly
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Fast idle due to overheating (possibly)
Hi everyone,
I was hoping some knowledgeable people on this lovely forum would be able to help me with a puzzling (at least for me!) Minor issue.
I have recently got my Minor 1000 running again after six months or so in storage. She started fine and ran well for a couple of weeks.
Recently, however, she has started to idle much too quickly. I think this may be cooling system related for a couple of reasons: firstly, I have inspected more obvious things (such as throttle cable return, mixture setting, etc.) and everything seems fine; secondly, the problem only starts after driving for a little while and seems to be worse when the weather is hot.
I would like to know if this could be the reason (and if so what to do about it) and also if I am mistaken, what other explanation there could be.
A thousand thank yous in advance.
I was hoping some knowledgeable people on this lovely forum would be able to help me with a puzzling (at least for me!) Minor issue.
I have recently got my Minor 1000 running again after six months or so in storage. She started fine and ran well for a couple of weeks.
Recently, however, she has started to idle much too quickly. I think this may be cooling system related for a couple of reasons: firstly, I have inspected more obvious things (such as throttle cable return, mixture setting, etc.) and everything seems fine; secondly, the problem only starts after driving for a little while and seems to be worse when the weather is hot.
I would like to know if this could be the reason (and if so what to do about it) and also if I am mistaken, what other explanation there could be.
A thousand thank yous in advance.
- geoberni
- Minor Legend
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Re: Fast idle due to overheating (possibly)
Have you checked the Choke set up?Little Mo' wrote: ↑Sat Aug 15, 2020 5:37 pm firstly, I have inspected more obvious things (such as throttle cable return, mixture setting, etc.)
If there's a little bit of Choke on, it'll idle fast and get more obvious once it's warmed up.
I've known cars of the 'Manual Choke era' where you could practically use the Choke as a hand throttle......
Basil the 1955 series II
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Re: Fast idle due to overheating (possibly)
Yes - do it manually at the carb using the jet control lever, which the choke cable operates.
Assuming you have not altered anything before the problem occurred, one check is to see if the air filter is excessively dirty or choked, as that will cause the idle to increase as well.
Assuming you have not altered anything before the problem occurred, one check is to see if the air filter is excessively dirty or choked, as that will cause the idle to increase as well.
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Re: Fast idle due to overheating (possibly)
I briefly tried running without the air filter and the problem persisted, although replacing the air filter is on my to do list.
I will check the choke in the morning like you suggest and report back. Thank you for your help.
I will check the choke in the morning like you suggest and report back. Thank you for your help.
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Re: Fast idle due to overheating (possibly)
Hello again,
The choke appears to be returning fully at the carburettor. What else could I try?
Thanks.
The choke appears to be returning fully at the carburettor. What else could I try?
Thanks.
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Re: Fast idle due to overheating (possibly)
OK, still hoping for an easy fix.....
1. Do you remember altering the throttle adjustment screw when you got the car "running again after six months or so"?
2. Are you sure the throttle cable or the pedal movement isn't sticking at all? When it starts idling too fast, can you tap up the accelerator pedal with your foot or wiggle the throttle linkage at the carb to get back to a slower idle? Try oiling the linkage at the carb end. Make sure there is nothing at the pedal end causing trouble - e.g. a rucked up bit of carpet. Check the throttle return spring is good and strong and fitted correctly.
1. Do you remember altering the throttle adjustment screw when you got the car "running again after six months or so"?
2. Are you sure the throttle cable or the pedal movement isn't sticking at all? When it starts idling too fast, can you tap up the accelerator pedal with your foot or wiggle the throttle linkage at the carb to get back to a slower idle? Try oiling the linkage at the carb end. Make sure there is nothing at the pedal end causing trouble - e.g. a rucked up bit of carpet. Check the throttle return spring is good and strong and fitted correctly.
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Re: Fast idle due to overheating (possibly)
Sadly I am beginning to feel such an easy fix is off the table. I haven't moved the throttle adjustment screw (it's as far out as it can be anyway). Also I have pushed the throttle off by hand at the carburettor when it is idling high and it doesn't make a difference.
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Re: Fast idle due to overheating (possibly)
Is the carb standard, eg 1 1/4" HS2? If it had been changed to a larger 1 1/2" HS4 these are usually equipped with waxstat jet mechanisms, which respond to changes in air temperature and could therefore account for the problem arising in hot weather? The waxstat mechanisms are known to be unreliable, but can be fairly easily modified. Bit of a long shot, but worth mentioning.
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Re: Fast idle due to overheating (possibly)
I'm reasonably sure it's a standard HS2. Either way, it doesn't have a waxstat mechanism on the jet. A nice idea though.
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Re: Fast idle due to overheating (possibly)
Could the carb piston be sticking at all as it drops?
Butterfly valve not closing completely for some reason?
Butterfly valve not closing completely for some reason?
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- Minor Fan
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Re: Fast idle due to overheating (possibly)
Retarded ignition can cause overheating.
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Re: Fast idle due to overheating (possibly)
Hi again,
Thanks for the suggestions. Sadly these things are now getting beyond my skill at fixing so I have booked her in to be looked at. If anyone's interested, I'll report back with what the problem was.
Thanks for the suggestions. Sadly these things are now getting beyond my skill at fixing so I have booked her in to be looked at. If anyone's interested, I'll report back with what the problem was.
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Re: Fast idle due to overheating (possibly)
Yes, its always interesting to hear conclusions to these issues - far too many threads just tail off in the middle, leaving people guessing. Good luck.
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Re: Fast idle due to overheating (possibly)
Hope it’s an easy fix. It’s always good to find out what it was in case we encounter the same issue.Little Mo' wrote: ↑Wed Aug 19, 2020 8:20 am Hi again,
Thanks for the suggestions. Sadly these things are now getting beyond my skill at fixing so I have booked her in to be looked at. If anyone's interested, I'll report back with what the problem was.
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- Minor Fan
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Re: Fast idle due to overheating (possibly)
Good luck, I hope it's an easy fix. I'd be really interested to hear what they find as I have the same problem!Little Mo' wrote: ↑Wed Aug 19, 2020 8:20 am Hi again,
Thanks for the suggestions. Sadly these things are now getting beyond my skill at fixing so I have booked her in to be looked at. If anyone's interested, I'll report back with what the problem was.
Best wishes,
Seb
1971 Adderley Park Traveller, "Peggy". 1098 engine, automatic transmission
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Re: Fast idle due to overheating (possibly)
Update:
I got Little Mo' back from the mechanic's today. He couldn't find anything specific which was causing the problem, but put it down to the fact that the engine hasn't had a general tuning in a while. This is what he did:
- Adjusted the tappets
- Adjusted the distributor timing
- Cleaned the ignition points
- Changed the spark plugs
- Changed the air filter
- Removed and cleaned the carburettor, then replaced it and adjusted the mixture nut
I have been for a fairly decent drive today and the problem seems (fingers crossed) to have been solved. Also, she runs a lot smoother than she did before the issue began, which is a nice bonus.
Thank you to everybody who gave me suggestions to try. This has been my first post on this forum and I have been made to feel very welcome.
Best of luck to you, Seb.
Thanks again everyone.
I got Little Mo' back from the mechanic's today. He couldn't find anything specific which was causing the problem, but put it down to the fact that the engine hasn't had a general tuning in a while. This is what he did:
- Adjusted the tappets
- Adjusted the distributor timing
- Cleaned the ignition points
- Changed the spark plugs
- Changed the air filter
- Removed and cleaned the carburettor, then replaced it and adjusted the mixture nut
I have been for a fairly decent drive today and the problem seems (fingers crossed) to have been solved. Also, she runs a lot smoother than she did before the issue began, which is a nice bonus.
Thank you to everybody who gave me suggestions to try. This has been my first post on this forum and I have been made to feel very welcome.
Best of luck to you, Seb.
Thanks again everyone.
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- Minor Legend
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Re: Fast idle due to overheating (possibly)
Happy days! And thanks for coming back. It is true that a general lack of tune can leave an engine under-performing and a good service and tune-up can improve things considerably, if overdue. Now enjoy driving your car!
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- Minor Friendly
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Re: Fast idle due to overheating (possibly)
Thanks, I certainly will.
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- Minor Fan
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Re: Fast idle due to overheating (possibly)
Thanks for letting us know - glad to hear Little Mo is back and better than before, have fun!
Seb
1971 Adderley Park Traveller, "Peggy". 1098 engine, automatic transmission