Stuttering/surging

[ossieoz]

Does anyone know if a carburetor vapor vent rubber plug isn’t opening or closing correctly, could this give the problem i have?


1961 Greenbrier, 1962 Rampside and 1964 Monza cab.

[bbodie52]

Mon Jun 11, 2018 4:18 pm

Does anyone know if a carburetor vapor vent rubber plug isn’t opening or closing correctly, could this give the problem i have?

I don't think so. Read the IDLE VENT SYSTEM — Fig. 3 paragraphs on page 4 of the attached DELCO ROCHESTER - Models H, HV Carburetor Service Guide. Page 5 describes the OFF-IDLE OPERATION — Fig. 4, which would come into play at slow speeds, when the vacuum advance also has its main impact. The accelerator pumps also support operation in this transition phase from idle to higher speeds.

This book does a pretty good job of describing operational theory and functional purpose of each of the Rochester H/HV fuel/air circuits and subsystems.

[srt]

Sounds like it might be running lean

srt 66 Corsa Turbo so-cal area

[ossieoz]

Sounds like it might be running lean

srt 66 Corsa Turbo so-cal area

I’ve increased the carb jet size from 49 to 51... both carb idle mix screws are backed out 2 turns... so if anything it’s running to rich?

Still haven’t solved my problem of stumbling... i have at idle a fluctuation of revs and not a steady one. Goes up and down slightly in a harmonic rythm... probably 520 to 550 rpm (difficult to say exactly as i have only a digital multi meter that hops around).


1961 Greenbrier, 1962 Rampside and 1964 Monza cab.

[ossieoz]

I’m going to go through everything tomorrow one more time... rockers, vacuum, points, etc etc after every check/adjustment i’ll start the car and see if it gets better. If i find out what’s the problem i’ll let you know...

Thanks guys for all the suggestions and help :)


1961 Greenbrier, 1962 Rampside and 1964 Monza cab.

[heavymetal1986]

Was this issue ever resolved?

[ossieoz]

Was this issue ever resolved?

Not yet... but hopefully I’ll get all the double checks done tomorrow


1961 Greenbrier, 1962 Rampside and 1964 Monza cab.

[ossieoz]

At long last I’ve found and solved the problem...

I have 2 sets of Wolf renovated carbs... in these 2 sets i have 1 set that don’t ‘match’ and one set that have one ‘bad’ carb. As i have now discovered when i swap the sets over it gave a similar problem with stuttering/surging.

When i took the ‘good’ carb from one set and married it to the matching ‘good ‘ carb... bingo... sweet running 102hp engine. At long last :)

What the fault is with the ‘bad’ carbs, i have no idea... yet. But I have one more Corvair engine experience under my belt... give myself another 20 years and I maybe can call myself a Corvair expert ;)

Thanks everyone for your input and help...


1961 Greenbrier, 1962 Rampside and 1964 Monza cab.

[SpyderFan]

was there ever any progress on this ? I have a similar issue and running out of ideas

[terribleted]

was there ever any progress on this ? I have a similar issue and running out of ideas

Read directly above this post. OP says it was a carb issue.