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post #1 of (permalink) Old 07-28-2003, 08:08 PM Thread Starter
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mc 2100 erratic idle

got it all together today, and idle is smooth but jumps to 1500 or so, then slowly drops to about 600, then jumps back up.

the venturis looked like they were dripping rather than spraying, so i pulled them out and have them soaking in carb cleaner, will go through them tomorrow.

question is, could the power valve be too low, should i look into changing it?

it doesnt seem like its a vaccuum leak.

any ideas?
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post #2 of (permalink) Old 07-29-2003, 05:36 AM
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Re: mc 2100 erratic idle

I had some slight problems getting the adapter gaskets/carb gaskets sealed on mine. Doesn't ound like a tell tale vac leak, but you might want to check anyway. I'm not familiar with your Carter, but could there be some computer hook up/problem that is still trying to control stuff? [img]images/graemlins/confused.gif[/img]
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post #3 of (permalink) Old 07-29-2003, 11:46 AM
 
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Re: mc 2100 erratic idle

There definately shouldn't be any dripping of fuel into the venturi's. You might want to re-check the float level by idling the motor, then shutting it off and removing the top cover from the carb. There should not be fuel overflowing. Take a look in a manual and it will give you the float level and for some years the height the fuel should be below the top edge of the carb.

You can check the power valve by removing it. There should be not fuel beneath the cover, unless the rubber diaphragm is ruptured. You can test the valve with you lips to see that it can be pulled closed with suction and that the diaphragm isn't ruptured.

The high idle speed indicates too much air getting in from somewhere. Either the throttle plates are partly open, or some other source such as an unintentional vacuum leak. If you have a manual choke, you should epoxy shut the vacuum passage going into the cast choke "bowl" to prevent it sucking in extra air, possibly dirt and water as well.

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post #4 of (permalink) Old 07-29-2003, 01:28 PM
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Re: mc 2100 erratic idle

Did you blow out all the passages in the idle circuit before assembly?

I have my floats set just a hair below the recommended for offroad. Sucks a bit on cloverleafed onramps, but does swell in the woods.
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post #5 of (permalink) Old 07-29-2003, 06:14 PM Thread Starter
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Re: mc 2100 erratic idle

1. checked the base gaskets previously and there was a slight gap, so i used a different gaket
2. once i clean and reinstall the venturis, ill update...
3. power valve is new, fresh rebuild but ill still doublecheck
4. no i didnt blow out the idle circuits. would it be worth tearing it down and doing that?
5. float level is good, i set it a little below reccommended level.
6. i tore out all the computer stuff when i nuttered it when the carter still lived there.
7. i did jb weld the choke bowl shut.
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post #6 of (permalink) Old 07-29-2003, 06:27 PM
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Re: mc 2100 erratic idle

1. OK, let's simplify.
2. If you've got a vacuum leak,
3. The carb'll go nuts.
4. Have you spritzed for a vacuum leak with Carb Cleaner or Water the[*]Carb [*]Base of the Carb [*]Intake Manifold.
5. If that test fails to uncover a vacuum leak..
6. Then you know the problem is internal to the carb.
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post #7 of (permalink) Old 07-29-2003, 07:39 PM Thread Starter
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Re: mc 2100 erratic idle

a vaccuum leak would be a constant high idle though, right?
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post #8 of (permalink) Old 07-29-2003, 07:45 PM
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Re: mc 2100 erratic idle

1. Nope, not always....
2. Put your hands over the Throat of the carb,
3. See if you can choke it down...
4. If it starves for air...
5. No leak...
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post #9 of (permalink) Old 07-29-2003, 07:57 PM Thread Starter
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Re: mc 2100 erratic idle

did that, it passed the test. i took it apart and i had omitted a gasket between the power valve and the carb body, so i installed the gasket and reassembled the carb.

went to put it on and test it, and torqued down the nuts a little extra to prevent leaks in the base gasket, and the nuts holding the studs in the adapter plate snapped. they are little thin aluminum jobs, so i cant blame them, but now im mad at the td adapter. is the mr gasket one any better?

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post #10 of (permalink) Old 07-29-2003, 10:50 PM
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Re: mc 2100 erratic idle

My Mr Gasket adapter seemed to work well, also came with alen headed bolts as I heard someone else say their's did not. Sounds like you were soooo close.
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