| [GMCnet] Carb [message #367913] |
Thu, 09 December 2021 18:03  |
Hanson Email
Messages: 110
Registered: March 2020
Karma: -1
|
Senior Member |
|
|
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:
|
|
|
|
| Re: [GMCnet] Carb [message #367918 is a reply to message #367913] |
Thu, 09 December 2021 19:01  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
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
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
