New to forum

There really was not a place to introduce myself and since I only like older trucks, I thought this the place to do so. So hello! lol

Enough about me... that is not why we are here... We are here because of a common love of automobiles that were built to last... not just to sell. It has been quite some time since my first truck, a 1969 Chevy stepside C-10 my father purchased for me at 15 years old, and am having a difficult time remembering...well almost everything about tuning my Rochester q-jet M4M that is on my 1986 Chevy Silverado LWB 305 5.0 automatic ALL original "real" truck... at least I think that is the carb I have... 17085226... anywho.

It is a little hard starting in the mornings... it never seems to idle back down once the warming process is complete, but I can go to lunch and it idles fine and then at night, it idles high again... I am thinking choke adjustment or replacement but could be completely wrong. I was also thinking vacuum leakage somewhere... I put SeaFoam in my tank and have almost used the tank and have noticed better idling/running since doing this.

Anyone have a suggestion of something I might be overlooking?? Response is GREATLY appreciated...
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Welcome to AF. Really sounds to me like a choke issue. Q-Jet chokes can be a real PITA. If your '86 has a "choke pull off" canister it needs to be checked for holding vacuum. The use of a hand held vac pump with gauge is the way to check it.

One issue with hard starting in the AM is fuel leaking out of the bottom of bowl past the solder on the holes drilled for the primary jet passages. The fix for this to clean, rough up and apply a good epoxy to these areas.

My suggestion would be, buy a rebuild kit ($15-25) for that Q-Jet # and follow the adjustment procedures for the choke and rebuild it with the kit.

Let us know..........

Thank you for the feedback. I took the air cleaner off and checked a few things, started the engine with no problem, then sprayed carb n choke cleaner on all the parts around it. I think between the sea foam and the cleaning (also done with q-tip on some bad parts) it now is starting really easy in the morning and driving/idling fine throughout the day. I watched a video on youtube about q-jets and called the guy i bought the truck from and asked him if he ever adjusted the choke for cool weather vs warm weather and he had never done it. I do know now even after talking to a few people that during colder weather the choke needs to be set a lil rich and turned back a lil lean for warmer weather... so far so good and loving driving my second "baby" around...