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| Idle far to high once hot. https://www.ausmini.com/forums/viewtopic.php?f=2&t=20497 |
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| Author: | Mick [ Sun Jun 25, 2006 12:34 am ] |
| Post subject: | Idle far to high once hot. |
I have my 1330 fitted with a RE13 cam, twin 1.25 SUs, lightened flywheel and 1.5:1 MS forged rockers. The tappet clearance is set to 17 thou. The problem I am having at the moment is that the engine revs are about 1000 rpm too high once the engine is hot. The cold starts are typical, and the normal idle as the car warms up for the first 40 minutes on the road is fine, but once the car seems to be at full running temps (oil is up to temperature, or after good run on the freeway) the revs at idle go through the roof. It usually idles around 1000 rpm, but will idle at about 2000 once this happens. I've checked for manifold leaks, and everything seems to be allright there, is there another reason why this might happen? |
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| Author: | drmini in aust [ Sun Jun 25, 2006 8:21 am ] |
| Post subject: | |
Mine idles OK at about 1300 hot (with RE282 cam) check throttles not sticking or shaft(s) worn- what carb(s)? |
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| Author: | LS1380 [ Sun Jun 25, 2006 8:58 am ] |
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Mick-I had the three dashpot screws come loose on one SU,this caused the idle speed to increase.Also I'm idling at 1300 to 1500. Hope you get it sorted. |
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| Author: | slinkey inc [ Sun Jun 25, 2006 11:14 am ] |
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Is this normal? My 1330 Cooper S idles at 1500 when warmed up. But my 1100S Clubman idles normally when warmed up. I've tried changing the floats as this caused the same problem of a mate of mines mini. I checked to see if the needle was bent, wasn't. I'm pretty sure in my case its my left carby. (I got twin 1.25 SU's) because it doesn't close the same as the other one, I'm not sure but it's gonna be checked out next week by Mini King. 
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| Author: | simon k [ Sun Jun 25, 2006 12:03 pm ] |
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drmini in aust wrote: Mine idles OK at about 1300 hot (with RE282 cam)
check throttles not sticking or shaft(s) worn- what carb(s)? I've had the shafts sticking - when the plates were open, they didn't stick because they could move from side to side, but when shut they jammed open a bit because the shaft was too long and just didn't have enough slack - I filed a couple of mm off it and problem solved get it hot and idling fast and see if the linkages are actually touching the idle screws - mine were way off |
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| Author: | Mini Mad [ Sun Jun 25, 2006 12:25 pm ] |
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slinkey inc wrote: Is this normal? My 1330 Cooper S idles at 1500 when warmed up. But my 1100S Clubman idles normally when warmed up. I've tried changing the floats as this caused the same problem of a mate of mines mini. I checked to see if the needle was bent, wasn't. I'm pretty sure in my case its my left carby. (I got twin 1.25 SU's) because it doesn't close the same as the other one, I'm not sure but it's gonna be checked out next week by Mini King.
If you have a wildish cam then the higher idle is fine, mine idles around 1500..it helps to keep a steady supply of oil to the rocker gear and valvetrain 
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| Author: | Mick [ Sun Jun 25, 2006 12:34 pm ] |
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The SUs are 1.25s, and don't appear to be sticking. They were rebuilt using a full kit some time ago but haven't seen too much use since then so are still very good. So there's probably not something too deep in all this, it should be simply a leak or something obvious? |
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| Author: | drmini in aust [ Sun Jun 25, 2006 4:47 pm ] |
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I'd check there is no slack between the throttle spindles and the body. And that the linkage is not fouling, the middle linkage should be slack in the outer forks (and have cable slack) when at idle. And it should have 3 return springs. |
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| Author: | TheMiniMan [ Sun Jun 25, 2006 5:57 pm ] |
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It`s a pretty normal situation ,,,,being that you say that it idles quite normal at 1000rpms when cold,,,so that tells me that you simply have the idle set too high in the first place. The choke mechanism on all SU carbs has the first part opperate only the high idle, the 2nd part then starts the choke,,,so once fired up, the choke cable can be set to release the choke but not all the way off leaving the "high idle" setting to sort the idle till it`s properly up to temp where you can then release the choke the whole way off to rely on the actual idle setting to do it`s job so,,,lower your idle setting & use the "high idle" part of the choke while its cold simple, , ,that`s the way they`re meant to be. of course make sure all else is perfect tho,
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| Author: | Mick [ Sun Jun 25, 2006 7:41 pm ] |
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I meant to get accross that there are three idles that the car has at the moment. 1. Cold (Brrrrrr cold): with the choke on 2. Warm: The engine picks up fine, no choke required at this point, maybe the first 20 to 30 minutes. Idles around 1000 or 1100 - situation normal 3. Warm (Hot): Everything is up to temp, not just the water. Mybe after 30 minutes or a good run down the freeway. Idles around 2000. So it's heat related. Maybe this points to the throttle linkages, or some other gap opening or shutting as temps get up there with heat soak. I'll keep looking but it's hard to spot as everything is sooo friggin hot under there when the problem rears it's head. |
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