Took my '66 110 convertible out for the first time in six weeks . . too many health issues to mention . . and now I find it stuh .. stuh .. stuttering. She runs fine, as in the cooler temps a couple months ago, but now after about 8 or 9 miles she starts stuttering like my old CW favorite Muh .. Muh .. Mel Tillis!! Head temp reaches about 115 degrees and, man what had been a fun drive becomes work! Instead of a nice rpm climb in 1st, if there is too much pedal, she balks until I lift off the gas a little. Same in 2nd & 3rd & 4th. Letting off the gas a little, she will cruise until I upshift and add throttle. Too much foot and she balks .. had a couple small backfires from the right side exhaust - no smoke.

Last winter she got new plugs, wires, points, condenser, battery. The dwell is at 32, carbs were balanced 3 months ago and she ran well .. in 60 degree weather .. it's now 84+ most afternoons going to 92 - soon to be 90s to 100?!

Ideas on what I should look at?

THANKS,
Dennis in Austin

Failing coil? Bad ground on the points plate? Just a couple of guesses.

David Clamp


1965 Corsa convertible - 140 4spd/3.55/AM-FM

2009 Porsche 911 Carrera


"Victory is mine!" - SG

Yukon, OK

Thanks David . . new coil but worth a check. I will also check on the grounding.

Kinda stumping . . .

You didn't happen to put ethanol gas in it last time?

Dave A.

62 Greenbrier "Shaggy" Daily Driver
63 Greenbrier "Velma" (SOLD!)
63 Rampside Future Project
63 Monza Vert
64 Monza Vert, Son's Project / Daily Driver

Puyallup, WA

Well, now *I* know what to look for.

A very common cause is the little black wire from the points to the coil cracks it's insulation at the grommet where it enters the distributor, or has frayed wires at the terminal ends.

Brent

Thanks all . .

Big Dave . . have only used 90 octane ethanol free gas since the rebuild last year. Would think that, if it were a fuel issue, it would be felt as soon as the car is started not after 5 + miles?

brentc . . the wire was new last year but will check that connection area.



Any other suggestions will be appreciated folks . . .

vapor lock.
debris in fuel bowls?
accelerator pump?

Check to make sure you distributor is not loose and that the timing has moved. I would also check the points plate for excessive wear. The points plate can be rebuilt but best to get another with a ground wire soldered from the base plate to the point mounting plate. Might want to try and set the points by feeler gauge, in case the dwell meter you are using isnt reading correctly.

1964 Monza Coupe
1965 Corsa 140
1967 Monza Coupe

Maryville, TN
U.S. 129 The"Tail Of The Dragon"

Thanks cfmann - Vapor lock was one of my considerations - how to you avoid/get past that issue?! As to debris and acc. pump - newly rebuilt cabs over the winter and new parts via the Clark's deluxe rebuild kits.

Thanks Ratt643 - Points were set by feeler gauge - meter was a check. Distributor is tight and the point plate was new during the winter. Ground wire from base plate to points plate? Since they are both bare steel and touching, I would think that to be adequate grounding? Since the base plate (just put a new one in my '68 too - replacing a Petronix) and points plates come in separate packages - wouldn't I need to solder a wire on? Isn't the wire to the negative coil post the grounding? This is all kinda confusing?! Please explain this in a little more detail - perhaps with photo?

collapsing rubber fuel line section?
fuel pump crapping out?

1966 Monza Convertible, 140HP-4 speed, Ermine White
1969 Monza Convertible, 110HP-PG, Frost Green, #3753

Black Mountain,NC

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stumpy Wrote:
-------------------------------------------------------
> Thanks cfmann - Vapor lock was one of my considerations - how to you avoid/get past that issue?! As to debris and acc. pump - newly rebuilt cabs over the winter and new parts via the Clark's deluxe rebuild kits.
>
> Thanks Ratt643 - Points were set by feeler gauge - meter was a check. Distributor is tight and the point plate was new during the winter. Ground wire from base plate to points plate? Since they are both bare steel and touching, I would think that to be adequate grounding? Since the base plate (just put a new one in my '68 too - replacing a Petronix) and points plates come in separate packages - wouldn't I need to solder a wire on? Isn't the wire to the negative coil post the grounding? This is all kinda confusing?! Please explain this in a little more detail - perhaps with photo?


Here is a link to Clarks for the points plate. If you have a new points plate, its probably not an issue. On worn points plates, when the vacuum advance pivots the points plate, the upper plate can loose its ground and cause the engine to stumble. Hence the wire soldered from the base of the points plate to the pivot plate.

[ssl.corvair.com]

1964 Monza Coupe
1965 Corsa 140
1967 Monza Coupe

Maryville, TN
U.S. 129 The"Tail Of The Dragon"

Thanks MtnVairMike - new electric fuel pump last Fall. All fuel lines are steel except for about 2" twice with the steel lines only an inch apart. Rubber lines also new.

Thanks Ratt643 - OK . . I see . . will definitely look at the distributor once the rains stop and I can remove the car cover. Seems I recall a soldered wire on the base plate - just not sure if it was on the '66 (last Fall) or the '68 recently? Will check both!! BTW I see you are in Maryville ... I graduated UT-Knoxville in '73 ... lived out near the airport - still miss my motorcycle rides to Cades Cove, Clingmans Dome, Cherokee Nat'l Forest and the other East Tennessee/North Carolina mountain roads - bet they're great fun in a Corvair too?!!

stumpy Wrote:
-------------------------------------------------------
> Thanks MtnVairMike - new electric fuel pump last Fall. All fuel lines are steel except for about 2" twice with the steel lines only an inch apart. Rubber lines also new.
>
> Thanks Ratt643 - OK . . I see . . will definitely look at the distributor once the rains stop and I can remove the car cover. Seems I recall a soldered wire on the base plate - just not sure if it was on the '66 (last Fall) or the '68 recently? Will check both!! BTW I see you are in Maryville ... I graduated UT-Knoxville in '73 ... lived out near the airport - still miss my motorcycle rides to Cades Cove, Clingmans Dome, Cherokee Nat'l Forest and the other East Tennessee/North Carolina mountain roads - bet they're great fun in a Corvair too?!!
Best drives in a Corvair are the Tail of the Dragon! I drive the dragon in my Vairs, along with drives to the Smokies.

1964 Monza Coupe
1965 Corsa 140
1967 Monza Coupe

Maryville, TN
U.S. 129 The"Tail Of The Dragon"

Finally had a nice sunny day today and looked at both Corvairs - both of the newly installed points base plates have the grounding wire. I also checked on the plate to coil wire and they are both fine.

So, the hunt for the stuttering continues. Will try to get out over the weekend for another test drive.

Any other suggestions will be appreciated greatly . . .

to defer you to a more intelligent source on vapor lock look at this webpage:

[axleaddict.com]

i think you have a fuel problem. I think if it ran fine/OK at cooler ambient air temps (or just idling in driveway), but after a drive around and a warm up, something thermal is causing your problem.

do you have insulators on the base of carbs?

are you running an electric fuel pump or mechanical?

is the fuel line return blocked?

double check fuel supply line. is it clear?

stone filter check at carb inlet?

air intake getting clean cool(er) air without obstruction? i.e. clean air filter?

another thought was you have debris floating around in the fuel system a particle is floating around in the fuel bowl and upon accelerating is get sucks into fuel stream....

did you clean or replace the jets when you rebuilt carbs? what size jets are you running?

WOW . . THANKS cfmann . . the article included is great - have skimmed it and will read in detail as soon as I peel the peaches for "she who must be obeyed" . . I do so like a good peach cobbler!!

As to your questions -

do you have insulators on the base of carbs? Yes, new with carb rebuilds late last Fall.

are you running an electric fuel pump or mechanical? New electrical pump last Fall.

is the fuel line return blocked? There is not a return line on my ‘66. There is one on my ‘68 and I think they weren’t introduced until maybe ‘67 or ‘68?? Can one be added??

double check fuel supply line. is it clear? Yes, I had checked that. Will check again.

stone filter check at carb inlet? Both new last Fall but will pull them & check.

air intake getting clean cool(er) air without obstruction? i.e. clean air filter? Yes, new last Fall.

did you clean or replace the jets when you rebuilt carbs? what size jets are you running? Jets were cleaned with carb rebuilds. Using original (though new) 52s.

another thought was you have debris floating around in the fuel system a particle is floating around in the fuel bowl and upon accelerating is get sucks into fuel stream.... The tank was cleaned, steel lines blown out, new rubber lines, the carb rebuilds, new fuel pump & pump controller - all last Fall.

The problem is that it will sit for 30 minutes and idle fine. The car will run very well for 8 - 10 miles and then the hesitation starts? Frustrating! Have only driven it 300+/- miles in six months. Since its old convertible top needs replacing, and we are having almost daily showers, I cannot take it out too often. Have the ‘68 in the garage at present and awaiting parts - not running - will have to exchange the vehicles ASAP. I will start at the carbs and move to the tank to see what can be found. Will also get a new in line filter - this one has only has the 300 miles on it! But, unfortunately, cannot see inside the metal canisters?!

THANKS for your thoughts . . .

Am I the only one who thinks this sounds like water in the fuel?

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WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.

stumpy:
I'm just trying to help, I couldn't hold a candle to some of the other guys here as my experiences are limited to some degree. I think I am a decent diagnostician though. ...maybe.... lol.
I know my '69's vairy well but not so much 65-66.
That said, if you look at Clarks, they indicate a 66 110 no smog standard shift (manual) runs a 49 carb jet and with smog standard shift, a 50 jet. I imagine you are smog-less so 49 might be your mark. you mention having 52 maybe to large? maybe you are flooding out/too rich when your laying into 2,3,4?
I'm no carb expert like Bob Helt, but your carbs may not even be original to your motor. someone could have swapped them, replaced them with another year type or rebuilt them with bigger jets prior to your involvement. I know there were subtle differences, year to year and application to application, do all you can to verify yours are for a '66 110/4 smog/no smog.
Clarks also makes a point to say all their rebuilt carbs come with #51 jets. So then gives me pause as to your problem if yours are 52's. but to be "proper" to 49 that might be just the difference you need!
I'm also assuming if you did the Delux kits you got new choke tabs. I bring this up as I alluded to a thermal problem before, and maybe after the 5-10 mile warm-up your chokes are not letting off completely? just a passing thought.
my experiences with elec fuel pumps is vair'ed (pun intended). make sure you have a good solid tight ground on the pump. i know when I mounted mine one time, it was a little finicky with placement and lines and wires in tight quarters, I'm sure you have no kinks up there.
nothing short of a fuel pressure gauge on the dashboard while your warming into a run to know what your psi is, the pump could be suspect, too much pressure maybe? a fuel regulator might be in order you decide.
look for a clear vial type in line fuel filter, then you can see your fuel quality!
i seem to recall my time here at CC that opinions on carb jets is somewhat a personal choice.
elec pump quality can be vaired too, some are specific to vair, some are more universal in nature, some are stronger/weaker psi than others...
if these don't solve, I'm fresh out of ideas.



Edited 1 time(s). Last edit at 05/30/2023 10:30PM by cfmann.