Vacuum question 85 Nissan 720

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Bluefalcon76
Posts: 2
Joined: Sun Sep 27, 2020 3:39 pm
Car: 1985 Nissan 720 4x4

Vacuum question 85 Nissan 720

Postby Bluefalcon76 » Tue Sep 29, 2020 8:10 pm

I just purchased an 85 Nissan 720 4x4. It’s got a bit of a rough idle, and not much power. It kinda feels like the secondary isn’t opening. I went through the vacuum lines, and repaired a couple. I was wondering what the proper vacuum readings should be? I have 20hg at an idle. When I accelerate it drops to 10, and back to 20 when I let off. Is that right? Seems like the vacuum should go up. I’ve never worked on one of these. Any help would be appreciated. Thanks.


Bluefalcon76
Posts: 2
Joined: Sun Sep 27, 2020 3:39 pm
Car: 1985 Nissan 720 4x4

Re: Vacuum question 85 Nissan 720

Postby Bluefalcon76 » Sat Oct 03, 2020 12:06 pm

Ok, maybe I didn’t post this in the right place. If I should be posting somewhere else, please let me know... Anyway, I believe the previous owner made adjustments to the carb while there was a vacuum leak. Not knowing what to do about the above problem, I went ahead and capped all the vacuum lines minus the vacuum advance. Now it won’t idle. I’m gonna look into adjusting the carb. Also, can anyone tell me what opens the secondary? When I open the throttle all the way, the secondary doesn’t open. Thanks for your time.


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