Fast idle due to overheating (possibly)

Discuss mechanical problems here.
Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Fast idle due to overheating (possibly)

Postby Little Mo' » Sat Aug 15, 2020 5:37 pm

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.

geoberni
Minor Legend
Posts: 1517
Joined: Fri Aug 04, 2017 11:19 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby geoberni » Sat Aug 15, 2020 6:15 pm

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.)
Have you checked the Choke set up?

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

Image

Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Little Mo' » Sat Aug 15, 2020 6:43 pm

geoberni wrote:
Sat Aug 15, 2020 6:15 pm

Have you checked the Choke set up?
Thanks for the reply,

As far as I can tell, the choke cable returns the full distance. Is there another way I could check whether the choke is fully off?

myoldjalopy
Minor Legend
Posts: 1549
Joined: Tue Jan 29, 2013 10:32 pm
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby myoldjalopy » Sat Aug 15, 2020 7:12 pm

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.

Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Little Mo' » Sat Aug 15, 2020 7:55 pm

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.

Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Little Mo' » Sun Aug 16, 2020 4:24 pm

Hello again,

The choke appears to be returning fully at the carburettor. What else could I try?

Thanks.

myoldjalopy
Minor Legend
Posts: 1549
Joined: Tue Jan 29, 2013 10:32 pm
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby myoldjalopy » Sun Aug 16, 2020 5:10 pm

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.

Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Little Mo' » Sun Aug 16, 2020 7:13 pm

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.

Mark Wilson
Minor Addict
Posts: 865
Joined: Fri Aug 26, 2011 12:42 pm
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Mark Wilson » Sun Aug 16, 2020 9:03 pm

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.

Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Little Mo' » Sun Aug 16, 2020 10:27 pm

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.

myoldjalopy
Minor Legend
Posts: 1549
Joined: Tue Jan 29, 2013 10:32 pm
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby myoldjalopy » Sun Aug 16, 2020 10:36 pm

Could the carb piston be sticking at all as it drops?
Butterfly valve not closing completely for some reason?

newagetraveller
Minor Fan
Posts: 353
Joined: Wed Feb 13, 2002 12:00 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby newagetraveller » Mon Aug 17, 2020 2:01 pm

Retarded ignition can cause overheating.

Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Little Mo' » 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.

myoldjalopy
Minor Legend
Posts: 1549
Joined: Tue Jan 29, 2013 10:32 pm
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby myoldjalopy » Wed Aug 19, 2020 8:33 am

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.

MorrisJohn
Minor Fan
Posts: 165
Joined: Sun Jun 21, 2015 9:41 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby MorrisJohn » Fri Aug 21, 2020 9:08 am

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.
Hope it’s an easy fix. It’s always good to find out what it was in case we encounter the same issue.
The Morris Minor, it’s one of the family.

Napoleon Boot
Minor Fan
Posts: 187
Joined: Wed Nov 21, 2018 7:48 pm
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Napoleon Boot » Sat Aug 22, 2020 5:55 pm

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.
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!

Best wishes,
Seb
1971 Adderley Park Traveller, "Peggy". 1098 engine, automatic transmission
Image

Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Little Mo' » Mon Aug 24, 2020 9:55 pm

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.

myoldjalopy
Minor Legend
Posts: 1549
Joined: Tue Jan 29, 2013 10:32 pm
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby myoldjalopy » Tue Aug 25, 2020 10:14 am

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! 8)

Little Mo'
Newbie
Posts: 9
Joined: Tue Jan 22, 2019 7:23 am
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Little Mo' » Tue Aug 25, 2020 6:38 pm

myoldjalopy wrote:
Tue Aug 25, 2020 10:14 am
Now enjoy driving your car!
Thanks, I certainly will.

Napoleon Boot
Minor Fan
Posts: 187
Joined: Wed Nov 21, 2018 7:48 pm
MMOC Member: Yes

Re: Fast idle due to overheating (possibly)

Postby Napoleon Boot » Wed Aug 26, 2020 12:33 pm

Little Mo' wrote:
Mon Aug 24, 2020 9:55 pm

Best of luck to you, Seb.

Thanks again everyone.
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
Image


Who is online

Users browsing this forum: No registered users and 8 guests