17085226 - What do I have here?

[Raoul Ross]

Picked this up on Craigslist but it seems sorta odd. Looks like a Replacement from the sticker but it's a big bore carb, note the 'bump'! From what I can research it's a 85-87 Chev/GMC truck.

[Kenth]

Nice unit for a performance build. Do a search on this forum for 17085226 and you'll find good info on it.

[Burd]

Look in the Q-Jet handbook.

[GSP7]

What is that round brass looking in the bottom of the round bowl area ? is that for a computer thing-ma-jig controlled carberator (1985)

[77cruiser]

I got one of those it's a CCC. I tried to do a outer booster removal trick but it didn't work out.

[Kenth]

1985/86 Q-jets in U.S. Trucks have dual capacity pump like this 17085226, which is NOT a Computer Control Carb.
When engine is cold, more fuel is needed for transition from idle to part-throttle.
When engine is warm less is required.
Dual pump solenoid is activated by coolant temperature sensor.
AT 170 °F pump solenoid energizes, dual capacity pump valve opens and pump capacity reduces by about one-half.

Just unhook the connector and it will work just fine like any M4 Quadrajet.

[Cliff Ruggles]

I would also block the passage under the plunger valve assembly.  Most of those valves are leaking, matter of fact I never tested on yet that wasn't.  Since it's not needed just fill the passage under it with lead, smack it gently with a flat punch, and build it just like any other late model SMAB Q-jet......