Qjet 17080213 stock primary jets and rods

[Shady Tree Garage]

A few years back I bought a rebuilt 17080213 for my 1984 K2500 P/U 4x4 350 w/TH400 Trans.  Gas mileage before and after was horrific <8 mpg.  It had been jetted .073 /.049.  Did what I could to research then and replaced them with .072/.050, which helped mileage a bunch >11 Mpg. Truck is used for basic street / hwy use, occasionally towing or running with a slide in camper.  I remember seeing a chart somewhere that listed what stock jetting was for this carb in various applications, but darned if I can come up with it now.  I am replacing the engine with a new crate 350 and while the carb is off I am cleaning it up a bit and wondering what the stock primaries would have been.  Does anybody have a listing of the stock jetting for this carb and application?  Thanks in advance for helping out the newbie!

[Ethan1]

 Welcome to CHP!

 Stock jetting and rods for that carb were, .072" Primary Jets, 50M Primary Metering Rods, "K" Secondary Hanger and DP Secondary Metering Rods.

[Ethan1]

 Application was used on the '80 Chevrolet/GMC Truck 350cid M/T Federal.

[Shady Tree Garage]

Thank you much Ethan!  I can't remember if the rods I used were for trucks ...  "M"  I think I'll pull the top off and check and record for future.  Also, I didn't set up the power piston assuming the rebuild guy did, but I am going to check that too.  One other question .. I checked the rear vacuum break the same way I did the choke pull-off and the rear break slowly eased out even though I was holding the tube closed.  I am assuming that means it is bad ... is that correct?  Thanks again for your help!

[Shady Tree Garage]

Back then, I bought a variety of jets and rods from Quadrajetparts.com, and I have been using a magnifying glass, bright light and glasses to try to see the numbers on the brand new rods out of the package, but they are just not marked.  The package has the rods as Q2550S and notes that they fit '75 and later Qjets and are .050".  Since I believe I got them all from the same place, I doubt I will know which they are by taking them out of the carb and looking.  Do you by chance know what the "S" after the number would denote? 

[Ethan1]

Thank you much Ethan!  I can't remember if the rods I used were for trucks ...  "M"  I think I'll pull the top off and check and record for future.  Also, I didn't set up the power piston assuming the rebuild guy did, but I am going to check that too.  One other question .. I checked the rear vacuum break the same way I did the choke pull-off and the rear break slowly eased out even though I was holding the tube closed.  I am assuming that means it is bad ... is that correct?  Thanks again for your help!

 Yes, I would definitely get a new rear vacuum break from Cliff.

[Ethan1]

Back then, I bought a variety of jets and rods from Quadrajetparts.com, and I have been using a magnifying glass, bright light and glasses to try to see the numbers on the brand new rods out of the package, but they are just not marked.  The package has the rods as Q2550S and notes that they fit '75 and later Qjets and are .050".  Since I believe I got them all from the same place, I doubt I will know which they are by taking them out of the carb and looking.  Do you by chance know what the "S" after the number would denote?

 I would get ahold of Greg Gessler and see what he says about that part number. He is the owner and I am sure he would know. Cliff should have those rods too.

[Shady Tree Garage]

Thanks again! You were right ... he said he used to denote them as "S" for "short" and he has changed it now to better reflect the truck version as "M", so I apparently have the correct rods in a package.  I can't find engraving on them, so I am going to replace what's there with these to be sure.  I will also get ahold of Cliff to get a rear vac break. I really appreciate your help.

[Shady Tree Garage]

Well I just removed the top of the carb and the rods and jets and I am glad I did because my memory was wrong.  It is still jetted 73/49M, which is the way it came from the re-builder.  I must have adjusted my power piston, bought the jets and rods and never replaced them.  When I pulled the jets, it is clear that a re-build and thorough cleaning is going to be needed.  There is some kind of debris or corrosion visible below the jets and the well opposite the accel. pump well (not sure what its called or is) is conical shaped (inverted) and the bottom of it is also full of debris of some kind.  The power piston did not need to be flicked as it was already loose with the nylon ring out of place and the ring appears white-ish and dried out   The carb appears to have been running very rich as there are black soot deposits throughout the primary and secondary venturis.  Can you tell me what that second well is for?  Also, any suggestions about a good cleaning method?  Thanks again!

[Ethan1]

Well I just removed the top of the carb and the rods and jets and I am glad I did because my memory was wrong.  It is still jetted 73/49M, which is the way it came from the re-builder.  I must have adjusted my power piston, bought the jets and rods and never replaced them.  When I pulled the jets, it is clear that a re-build and thorough cleaning is going to be needed.  There is some kind of debris or corrosion visible below the jets and the well opposite the accel. pump well (not sure what its called or is) is conical shaped (inverted) and the bottom of it is also full of debris of some kind.  The power piston did not need to be flicked as it was already loose with the nylon ring out of place and the ring appears white-ish and dried out   The carb appears to have been running very rich as there are black soot deposits throughout the primary and secondary venturis.  Can you tell me what that second well is for?  Also, any suggestions about a good cleaning method?  Thanks again!

 This?

 http://www.crankshaftcoalition.com/wiki/File:ANEROID_OR_FILLER_SPOOL_DETAILS.jpg

 As for cleaning, there are several methods. Ultrasonic cleaning is probably the best, but most people use ChemTool and then soda blast the carburetor.

[Shady Tree Garage]

Ah Ha!  So that's the APT jet ... well it looks completely clogged up with s...tuff!  Well OK then, got my work cut out for me .. I will look into chem tool and soda blasting,  and do some reading on the APT.  The job just keeps getting bigger   ... had a spun rod bearing, so I decided to just replace with the crate 350 to expedite, then found a huge crack in the bell housing of the TH400, so a used one is on its way ... yikes!  ah what the heck, might as well re-build the carb too.  Good thing the body and frame of this beast is in good shape.  It'll be great when its done ... probably should find some wood to knock on though.  Thanks Ethan.

[Ethan1]

 Not a problem. Glad I could help.