Chevrolet Repair: Old GMC throttle issue, throttle linkage, mechanic friend

Question
Hi, I own an Old GMC 3ton truck that is having some issues. well first off ill tell you i know little about this truck but from what i know it is an old (80s somewhere id put it) 3ton with a dumping box. the engine is a gas job the size i do not know. it has a 4 speed manual transmission with reverse. 68000 original miles. last year it was perfectly operational just had no need to use it. left it in the work shop throughout the winter and then decided to get it going about 2 weeks ago due to a need of rocks for a garden. the key had been lost over the winter so took the ignition out and to a locksmiths to be rekeyed. that all done reinstalled the ignition and after a initial fluid check and walk around cranked it over. the engine started but ran very rough. didnt stay running for long either. stalled out. attempted to check the fuel figuring the fuel was old and no good. tank had about 1/4 in it so filled it up with fresh fuel after consulting a mechanic friend who said the old fuel wouldnt hurt it at all just might bog down or something. after adding the new fuel attempted to start it again and it fired but idles very rough. my throttle for some reason has no response which im thinking is the main issue. not sure. checked the cables the throttles working fine. even went straight to the carb and pushed the throttle cable and still no response. what could the issue be? Thanks Tom for any help or advice you can offer.
sincerely - Colt from Manitoba Canada

Answer
HI COLT,I WILL ASSUME THIS IS A 4 BR QUAD CARBURETOR,,YES,I AM GOING WITH THIS. THIS IS TYPICAL WHEN A CAR OR TRUCK SITS FOR A LONG PERIOD. THE ACCELERATOR PUMP ROD STICKS DOWN IN THE TOP SECTION OF THE FLOAT BOWL..TAKE OFF THE AIR CLEANER AND FOLLOW THE THROTTLE LINKAGE TO THE TOP SIDE OF THE CARB YOU WILL SEE A ROD GOING INTO THE CARB HOOKED UP TO THE THROTTLE LINKAGE,OIL THIS ROD IN THE TOP SECTION OF THE CARB,YOU WILL NEED TO MANUALLY LIFT THIS ROD UP AND PUSH IT DOWN AGAIN SEVERAL TIMES TTIL IT FREES UP,USE SOME OIL ON IT. IF THIS ROD IS FREE,THEN THE ONLY THING LEFT IS THE ACCELERATOR PUMP ISIDE THE CARB IS SHOT. THIS WOULD BE RARE HOWEVER FROM ONLY SITTING 6 MONTHS OR SO.THERE COULD BE DIRT INSIDE THE JET HOLES INSIDE THE CARB.IF SO A REBUILD WILL BE NEEDED..AS FAR AS RUNNING ROUGH THE PLUGS ARE PROBABLY A BIT FOWLED OR DIRTY FROM SITTING CONTAMINATION FROM OLD FUEL..GET IT UP AND RUNNING FIRST AND THIS SHOULD CLEAR ITSELF OUT. IT IS A CHEVY IT HAS TOO...I HOPE THIS HELPS YOU AND IF YOU NEED MORE INFO PLEASE GET BACK TO ME..WHEN YOU LEAVE THIS SITE WOULD YOU PLEASE RATE MY ANSWER.THANK YOU,, TOM.