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What did you do with your MG Midget today?

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66jalopy Avatar
66jalopy Silver Member Phillip Jolliffe
Lake City, FL, USA   USA
If it is vacuum leak it should be very lean and probably would starve for lack of fuel rather than run wide open. Wide open is butterflies not closing. Are the springs all on there? Are you running SU carbs? If so with the air filter off, does it suck the pistons all the way up? It is even possible that the screws came out of one of the butterflies, specially if they have been replaced and no locktite was used.

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jimbvd Platinum Member Jim Bravard
Hopkinsville, Ky., USA   USA
I did check that. I stopped the engine, checked that, and then unscrewed it til it wasn't touching. Then started the car. It ran at 18000 rpm and wouldn't adjust all all. That's why I'm thinking I have a vacuum leak. jim

In reply to # 3680538 by MiniCobra
In reply to # 3680511 by jimbvd Started it yesterday afternoon and it ran wide open. Adjusting screws had no effect. From what I can find, this is a big vacuum leak. I sprayed carb cleaner in different places, but nothing. I am going to inspect the vacuum hoses and probably replace them.

I had a brittle rubber piece coming from the fuel filter to the carb. inlet line a while back. Thinking this may be a similar situation. jim

Any thoughts appreciated.

Jim,
If really wide open, sounds like throttle linkage. Did you check linkage and make sure it was on the idle stop screw and not binding?
Mike

Tveditr Eric EN
Indianapolis, USA   USA
1962 MG MGA
1971 MG Midget
Are you sure timing is right?

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MiniCobra Avatar
MiniCobra Mike B
Weatherford, TX, USA   USA
1973 MG Midget Conversion "Mini Cobra"
1998 Dodge Dakota Pickup "Dak"
2006 Nissan 350Z Roadster "Rose-Z"
In reply to # 3680605 by jimbvd I did check that. I stopped the engine, checked that, and then unscrewed it til it wasn't touching. Then started the car. It ran at 18000 rpm and wouldn't adjust all all. That's why I'm thinking I have a vacuum leak. jim

In reply to # 3680538 by MiniCobra
In reply to # 3680511 by jimbvd Started it yesterday afternoon and it ran wide open. Adjusting screws had no effect. From what I can find, this is a big vacuum leak. I sprayed carb cleaner in different places, but nothing. I am going to inspect the vacuum hoses and probably replace them.

I had a brittle rubber piece coming from the fuel filter to the carb. inlet line a while back. Thinking this may be a similar situation. jim

Any thoughts appreciated.

Jim,
If really wide open, sounds like throttle linkage. Did you check linkage and make sure it was on the idle stop screw and not binding?
Mike

Jim, I hope you meant 1800 RPM not 18000. My vacuum leak made me raise my idle to be at 1200 RPM in neutral and ran rough in gear. After fixing I could drop idle in neutral to 800 or so and its now steady in gear. But I don't know anything about SU carbs. Looks like Phillip has some good input there.
Mike

thebeav55 Paul W
Tonawanda, NY, USA   USA
I'm sure he meant 1800.....No way in heck one of these engines is going to turn 18 K. If they did, I'd put wings on my car......"Look !!!....Up in the sky......It's a....."

jimbvd Platinum Member Jim Bravard
Hopkinsville, Ky., USA   USA
Sorry about the mix up. Yes 1800 RPM, not good at typing and didn't proofread very well. It is also a Weber carb. Came on the car when bought. Have sourced almost everything for conversion back to SU carbs, but won't do that til I retire next year.
Thanks for the input, though. I have always been mechanically oriented, just never cared about working on cars til I bought the midget. jim

MiniCobra Avatar
MiniCobra Mike B
Weatherford, TX, USA   USA
1973 MG Midget Conversion "Mini Cobra"
1998 Dodge Dakota Pickup "Dak"
2006 Nissan 350Z Roadster "Rose-Z"
In reply to # 3680720 by jimbvd Sorry about the mix up. Yes 1800 RPM, not good at typing and didn't proofread very well. It is also a Weber carb. Came on the car when bought. Have sourced almost everything for conversion back to SU carbs, but won't do that til I retire next year.
Thanks for the input, though. I have always been mechanically oriented, just never cared about working on cars til I bought the midget. jim

I had a weber on my 78 Fiat X1/9. I would check to make sure the throttle plate is closed all the way , not loose on the shaft and the throttle shaft is not worn and loose in its bore as well as checking for vacuum leaks.

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MiniCobra Avatar
MiniCobra Mike B
Weatherford, TX, USA   USA
1973 MG Midget Conversion "Mini Cobra"
1998 Dodge Dakota Pickup "Dak"
2006 Nissan 350Z Roadster "Rose-Z"
In reply to # 3680727 by MiniCobra
In reply to # 3680720 by jimbvd Sorry about the mix up. Yes 1800 RPM, not good at typing and didn't proofread very well. It is also a Weber carb. Came on the car when bought. Have sourced almost everything for conversion back to SU carbs, but won't do that til I retire next year.
Thanks for the input, though. I have always been mechanically oriented, just never cared about working on cars til I bought the midget. jim

I had a weber on my 78 Fiat X1/9. I would check to make sure the throttle plate is closed all the way , not loose on the shaft and the throttle shaft is not worn and loose in its bore as well as checking for vacuum leaks.

Also make sure you are not stuck on the choke fast idle.

jimbvd Platinum Member Jim Bravard
Hopkinsville, Ky., USA   USA
Somehow I missed Philip and Eric's comments. I tuned it myself, but wasn't really sure I had done the correct procedure, as it still was not running right. I took it to a fella that timed it for me when I first bought the car a couple of times, so I'm pretty sure that's correct.

There is a piece threaded to the carb and hose barb on the other end down low on the carburetor body. I don't know why it's there or what purpose it was to have served. I'll attach a picture of it. Whoever put it on, had put a rubber cap over the hose barb end. I accidentally knocked that off one time and the car ran really high RPMs. That's why I was feeling that it probably would be a vacuum leak. jim

I took that brass piece out and I'm going by the auto parts place to get a plug for it. That way that will eliminate any possible air sucking into that point.

In reply to # 3680727 by MiniCobra
In reply to # 3680720 by jimbvd Sorry about the mix up. Yes 1800 RPM, not good at typing and didn't proofread very well. It is also a Weber carb. Came on the car when bought. Have sourced almost everything for conversion back to SU carbs, but won't do that til I retire next year.
Thanks for the input, though. I have always been mechanically oriented, just never cared about working on cars til I bought the midget. jim

I had a weber on my 78 Fiat X1/9. I would check to make sure the throttle plate is closed all the way , not loose on the shaft and the throttle shaft is not worn and loose in its bore as well as checking for vacuum leaks.



Edited 1 time(s). Last edit at 2018-02-13 03:10 PM by jimbvd.

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hoggie Avatar
hoggie Mike Hogan
Oklahoma City, OK, USA   USA
Vacuum advance connection??

MiniCobra Avatar
MiniCobra Mike B
Weatherford, TX, USA   USA
1973 MG Midget Conversion "Mini Cobra"
1998 Dodge Dakota Pickup "Dak"
2006 Nissan 350Z Roadster "Rose-Z"
In reply to # 3680755 by hoggie Vacuum advance connection??

It does look like manifold vacuum, but does the Midget use manifold or ported vacuum for advance. If this is backwards it would effect timing at idle.



Edited 1 time(s). Last edit at 2018-02-13 03:51 PM by MiniCobra.

djclinton Avatar
djclinton Dennis Clinton
Mesquite, NV, USA   USA
1964 Ford Ranchero "Red Rocket"
1966 Other Custom "Green Machine"
1979 MG Midget 1500 "Bridgette(brown Midget)"
I went out and looked at my weber(on a 1500). On that side of the carb, I have two vacuum attachments: 1 goes to the vacuum advance on the distributor(very small). 2 goes to the anti-run on valve. On yours, you should not have the run-on valve but my connection is about the same size of yours.

jimbvd Platinum Member Jim Bravard
Hopkinsville, Ky., USA   USA
Mike, that is how this started. Mike (mini cobra) mentioned checking the vacuum advance. I asked how to do that and it proceeded from there.

In reply to # 3680755 by hoggie Vacuum advance connection??

jimbvd Platinum Member Jim Bravard
Hopkinsville, Ky., USA   USA
Dennis, on my Weber, the vacuum advance line comes from the engine side of the carb and is very small. This is on the opposite side. I looked in a catalog and did not see anything in that spot. jim

Colonel musturd 79 Avatar
Colonel musturd 79 Michael McKinney
Winchester, VA, USA   USA
1978 MG Midget 1500 "Colonel Mustard"
1987 Pontiac Fiero "SILVER BULLET"
That fitting installed in your intake is a modification to replace the pcv system that was removed when your car was converted to a Weber.



Amore della Strada
For the love of the road

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