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Old 28-08-2011, 08:48   #1
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New Member Question Regarding Idle Speed

Hi all,

Sorry if this has already been posted somewhere but I can't find it.

I have a 1980 volvo md7a that seems to run fine except it cuts out when I put it into neutral. If I put it into neutral really slowly then it will idle but with a way too slow tickover.

I can't seem to find anywhere to adjust the idle speed, but is that the problem anyway.

Thanks for any help

Jeff
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Old 28-08-2011, 10:14   #2
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Re: New Member Question Regarding Idle Speed

Welcome Aboard Cruisers Forum Jeff

Not sure about that Volvo, but you should be able to adjust the linkage at the pump wgere the cable hooks up..
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Old 29-08-2011, 06:56   #3
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Re: New Member Question Regarding Idle Speed

Greetings and welcome aboard the CF, Jeff.
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Old 29-08-2011, 07:28   #4
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Re: New Member Question Regarding Idle Speed

Follow your throttle cable down to where it attaches to the injection pump. It usually attaches to a lever on the injection pump that will rotate as the throttle is moved from idle to full power. On this lever or on the the injection pump will be a screw that will stop the lever from being rotated when the throttle is returned to idle. Just like on an old auto engine carb, this screw is the idle adjustment screw. - If there is no screw then ask a diesel mechanic who is familiar with that make/model engine.
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Old 29-08-2011, 08:16   #5
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Re: New Member Question Regarding Idle Speed

Thanks guys,

I think I've found the screw you're talking about. Would it have a locking nut do you know? I found one on the lever and had a go at adjusting it today but it didn't seem to make much difference. When I tightened it the engine stalled, however when I loosened it, it didn't seem to make any difference.

Thanks in advance to any other suggestions.

Cheers

Jeff
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Old 29-08-2011, 15:46   #6
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Re: New Member Question Regarding Idle Speed

Normally the screw presses on a tab or plate and holds the throttle lever of the injection pump open a varying amount. You watch the lever and if it moves(rotates) as you adjust the screw then it is the idle adjustment. A locking nut is commonly used to keep the screw from moving.
- - If the engine stalls or wants to quit when you make minor adjustments in the idle speed then there is something wrong with the injection pump. For that you will need a good diesel mechanic to diagnose the problem.
- - However, when advancing the throttle on a diesel from idle it is not uncommon for the engine to hesitate or slow down a little before it picks up rpm's. On my Perkins 40 year old diesel I normally "goose" the throttle a couple of times to get the rpm's to increase from idle. You learn want your particular engine wants and feels/sounds like over time.
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Old 29-08-2011, 16:15   #7
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Re: New Member Question Regarding Idle Speed

Jeff, are you aware that the entire service manual is a free download online. Enter MD7A--and presto--
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Old 30-08-2011, 06:11   #8
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Re: New Member Question Regarding Idle Speed

Thanks osirissail, I'll check that out.

Yes Blue Stocking, thanks for that but I've already downloaded the manual but unfortunately it doesn't tell you how to adjust the idling speed at all.

Cheers
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Old 30-08-2011, 09:22   #9
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Jeff,
Welcome to CF. I had a similar issue with a MD6b. You might check the engine stop cable/lever. If the cable is not releasing the lever or the lever is stuck you not get enough fuel to the engine.

Paul
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Old 04-09-2011, 14:16   #10
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Re: New Member Question Regarding Idle Speed

Thanks for that Paul

However I checked the stop cable and it's fine. I think however I may have found the problem. It appears the pump lever is bent upwards and it appears that the idle adjustment screw is not actually making the correct contact. I'm going to get someone to have a look at it.

Thanks all for all your help.

Cheers

Jeff
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