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High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 06, 2019 02:35PM

FINALLY got my 61 Monza on the road yesterday and have been driving it around.

I have noticed that in neutral it idles at around 1200rpm. In drive, it drops down to 700-800rpm (Or somewhere around there). Usually after a drive and I put it into neutral, the neutral idle speed goes down to around 1100rpm.

I have also noticed that on level ground, as soon as I shift to drive and let up on the brake, it creeps forward. Same in reverse.

1. Is this creeping normal? Its my first Corvair and PG so I do not know what to expect.

2. Is my neutral idle speed in the acceptable range?

Both carbs are new and in sync (Owner said so and the car runs nice and smooth with plenty of power so Id assume he did a good job).

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 06, 2019 03:23PM

Just ordered a unisyn. After some searching around, seems like both rpms are way too high.

Is it possible the vacuum modulator could be bad and be causing a vacuum leak? Transmission shifts great and smooth.

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 06, 2019 03:34PM

Went out to double check the rpms. In neutral, it is about 1000 rpm, and in drive or reverse it is around 600-700rpm. So lower than I originally thought but still probably too high.

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Re: High idle and pulling in drive or reverse
Posted by: joelsplace ()
Date: April 06, 2019 03:45PM

That is too high and yes it will creep on flat ground but nothing too noticeable. The high idle will cause it to creep a lot. You should be able to get the neutral idle speed down below 700 without too much trouble if the engine and carburetors are in good shape.
Yes the vacuum modulator can cause a vacuum leak. Pull the hose off at the modulator and if any fluid is present it is bad. A bad modulator will cause smoke and you will lose transmission fluid.

Joel
Northlake, TX
4 Ultravans, Lost count at 100 Corvairs...

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 06, 2019 03:58PM

I haven't seen any smoke yet or any changes in transmission fluid level.

I'll try and balance the carbs once I get the tool. Engine only has 50k so fairly good shape I'd guess, and carbs are new.

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Re: High idle and pulling in drive or reverse
Posted by: stitch ()
Date: April 06, 2019 04:24PM

Just about every automatic car I've ever had will 'Creep-a-bit' iffin you put it in Drive or Reverse without your foot on the brake!

"If you can't fix it with a Hammer, you have an Electrical problem."
Stitch...
Schertz, Texas.
(Smallish town/burg 17 mi. NE of San Antonio)

'Ms Penny'
!967.. 4th body
8th off the line

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Re: High idle and pulling in drive or reverse
Posted by: MattNall ()
Date: April 06, 2019 04:40PM

If you are not familiar with Balancing Airflow and using the Unisyn...print this out and have it with you!

Balancing your carbs in plain English...from our FAQ's





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 06, 2019 06:28PM

Perfect! Just what I needed. Should this balance be done in drive or neutral? I have read you want it running smoother in drive versus neutral, and its hard to get both perfect, so go for smooth drive?

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Re: High idle and pulling in drive or reverse
Posted by: MattNall ()
Date: April 06, 2019 06:51PM

Airflow Balancing is done in Neutral...


"In Drive Idle Quality" is done with a warmed up engine AND Air filters on, since you should only need to adjust "idle Mixtures"..

Remember Idle Mixscrews do NOT need to be the same in each carb

You turn one in until engine slows down... then back out for smoothest idle. then other side, then repeat until you are Happy.

Here's what you are shooting for..... this car / engine was adjusted 10 k miles before this video was made.







MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 06, 2019 06:57PM

Ah, ok, I understand. The neutral balance is the "reference" balance I guess you could say. Thank you for all of your info! Vairy helpful

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Re: High idle and pulling in drive or reverse
Posted by: MattNall ()
Date: April 06, 2019 07:03PM

Let us know how it turns out!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 07, 2019 10:58AM

Took it out for a 30 minute drive today. When it is started and the engine is cold, it idles at 1000rpm, however after some driving, it shoots up to 1500rpm at neutral, but drive idle stays the same at around 700! There is also a slight miss sometimes when stopped at a stop light. Barely detectable.

I have read that it is probably the distributer going bad. I have no idea how old it is, probably original (Or at least 20-30 years old) and never rebuilt. The spark plug wires are all old and cracked so Id say it is. Im thinking the whole thing just needs a fresh tune up.

Does this sound like it could possibly be the issue? Only the neutral idle speed raises, the drive or reverse speed stays the same. It shifts smoothly into gear when cool and neutral rpm is 1000, but when hot and neutral rpm is 1500 it slams into gear.

There is also the old vacuum modulator, but not sure it would cause this issue only when hot?

???

IF it IS probably just needing a tune up, does this look like everything I will need?
[californiacorvairparts.com]
[californiacorvairparts.com]
[californiacorvairparts.com]



Edited 2 time(s). Last edit at 04/07/2019 11:04AM by Johnnya101.

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Re: High idle and pulling in drive or reverse
Posted by: MattNall ()
Date: April 07, 2019 11:30AM

Per my instructions...

Engine must be hot [ after a drive ] when idle Quality is adjusted...as well as speed.

Just remember...

Shut engine off.... and just BOTH carb's idle SPEED screws exactly the same

Restart and see what you have... go drive it again...





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 07, 2019 11:33AM

Ill try that once I get the balancer, but I am just talking about the 1000rpm to 1500rpm when hot for right now. I dont think that would be related to the carbs.

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Re: High idle and pulling in drive or reverse
Posted by: MattNall ()
Date: April 07, 2019 11:37AM

Believe me it is! Get the neutral 1500 / hot rpm down to 600!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: High idle and pulling in drive or reverse
Posted by: TomW ()
Date: April 07, 2019 11:42AM

#1 Replace those old, cracked Plug wires!!

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 07, 2019 11:43AM

Ok then, Ill update once I get the tool. Im going to mark the screws right now in their current position and just see if I can get it lower without the balancer (The carbs seem balanced right now). If any issues arise Ill turn them back to where they were and wait for the tool.

Can I do the quick adjustments without unhooking any of the linkages? I wont be checking with the unisyn since I dont have it yet.



Edited 1 time(s). Last edit at 04/07/2019 11:44AM by Johnnya101.

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Re: High idle and pulling in drive or reverse
Posted by: stitch ()
Date: April 07, 2019 11:51AM

Matt, years ago you posted how to make a home made manometer with tubing, brake fluid...etc. I actually made one while waiting for my Uni-syn to be shipped. Couldn't re-find the instructions but perhaps Johnnya101 could benefit...confused smiley

"If you can't fix it with a Hammer, you have an Electrical problem."
Stitch...
Schertz, Texas.
(Smallish town/burg 17 mi. NE of San Antonio)

'Ms Penny'
!967.. 4th body
8th off the line

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 07, 2019 01:22PM

Update

Called the PO and asked if he balanced the carbs and set it for the correct owner. He said he did. He said check the choke (it's manual).

Yup. You guessed it. I've been driving it fully choked. As soon as I opened them up, neutral idle dropped down to around 600ish.

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Re: High idle and pulling in drive or reverse
Posted by: Johnnya101 ()
Date: April 07, 2019 03:54PM

OK, another update once again.

It was almost to the point of stalling out once I fixed the choke and it was open. I adjusted the mixture screws and unscrewed them about 3/4 turn. Now it doesnt stall and the neutral idle is around 750 rpm and drive idle is around 550. No stalling and doesnt sound like it will. I took it for a quick drive, got it fully warmed up. Idle doesnt raise noticeably now once warmed up, and no more pulling or bangs when shifting into drive or reverse.

The new minor issue is that it has a minor stumble or rumble I guess, but only when idling. Kind of similar to this video, but less so: [www.youtube.com]

Playing with the mixture screws further did not do much. When driving, it is very smooth and is nice, no rumbling or stumbles. This is my first carbureted car, so maybe thats just how they are? Theres also sometimes a hesitation when pushing down the throttle, but only if I push down a lot, if its minor it has instant feedback. New balanced carbs. Perhaps it could be related to the vacuum modulator? Should probably change that...

Reading this thread: [corvaircenter.com] Maybe I should try richening it slightly more and see if the hesitation at least will go away.



Edited 2 time(s). Last edit at 04/07/2019 04:00PM by Johnnya101.

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