Carb

[Dean The ResourcefulNorse]

Working on a coach , 455 newly overhauled, approx 1000 miles, owner
complained of dieseling when shutting off and low power at altitudes. We had
the carb overhauled by shop that knows what he is doing, but overhauls what
is there. The carb is the wrong number and has been modified to fit. And all
ports are direct vacuum. Mostly does not diesel when vacuum removed from
distributor. When we retard timing back from 9 degrees, it doesn't want to
"rev" up. Also having trouble getting the motor to warm up even tho I put in
a 195 thermostat. Chasing my tail here.

Any thoughts would be appreciated.

Dean hanson

Fremont.

 

[jim kanomata1]

Set the timing back to 10-12 degrees and SLOW the Idle to 700RPM

> Working on a coach , 455 newly overhauled, approx 1000 miles, owner
> complained of dieseling when shutting off and low power at altitudes. We
> had
> the carb overhauled by shop that knows what he is doing, but overhauls what
> is there. The carb is the wrong number and has been modified to fit. And
> all
> ports are direct vacuum. Mostly does not diesel when vacuum removed from
> distributor. When we retard timing back from 9 degrees, it doesn't want to
> "rev" up. Also having trouble getting the motor to warm up even tho I put
> in
> a 195 thermostat. Chasing my tail here.
>
> Any thoughts would be appreciated.
>
> Dean hanson
>
> Fremont.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502

 

[jim kanomata1]

Also check the distributor mechanical is free and not binding or
dragging and the throttle vac port is hooked to the distributor.

> Set the timing back to 10-12 degrees and SLOW the Idle to 700RPM
>

>
>> Working on a coach , 455 newly overhauled, approx 1000 miles, owner
>> complained of dieseling when shutting off and low power at altitudes. We
>> had
>> the carb overhauled by shop that knows what he is doing, but overhauls
>> what
>> is there. The carb is the wrong number and has been modified to fit. And
>> all
>> ports are direct vacuum. Mostly does not diesel when vacuum removed from
>> distributor. When we retard timing back from 9 degrees, it doesn't want to
>> "rev" up. Also having trouble getting the motor to warm up even tho I put
>> in
>> a 195 thermostat. Chasing my tail here.
>>
>> Any thoughts would be appreciated.
>>
>> Dean hanson
>>
>> Fremont.
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
>
> --
> Jim Kanomata ASE
> Applied/GMC, Newark,CA
> jimk
> http://www.gmcrvparts.com
> 1-800-752-7502
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502

 

[john r. lebetski]

There is a Tree or thermal vacuum switch front of the intake manifold It has 3 ports D for distributor, M for manifold and C for carb. 99% of the
time coolant is below snap switch point (about 220F) and ported vacuum from the bottom front drivers port goes to the distributor This means no vacuum
advance at idle in normal conditions. I suggest you run fresh vac hoses according to the factory vacuum diagram. I have it saved on my phone but too
large a file for this platform. There is a T in the nanifold line as well so study carefully.
--
John Lebetski
Woodstock, IL
77 Eleganza II