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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Jeff86inMS on March 20, 2013, 05:43:54 pm

Title: Starting hot 1986 305
Post by: Jeff86inMS on March 20, 2013, 05:43:54 pm

Hello all!  I am having an issue I need some help with.  I have a 1986 Chevy C-10 with a 305 engine.  It is becoming increasingly hard to start after driving for a while.  For example,  I can leave work, drive 30 minutes home, take son to practice, shut off truck watch practice for an hour, get back in the truck and have to really pump the pedal to get it to start.  It starts cold with no issues.  Can anyone tell me what to check first? I've read a little about vapor lock, but not sure how to correct if that is even the problem. Thanks!

Jeff

Title: Re: Starting hot 1986 305
Post by: Captkaos on March 20, 2013, 10:12:12 pm

what does it do if you don't pump the gas?  how hot is it there?  Vapor lock would be an issue if it was REALLY hot...

Title: Re: Starting hot 1986 305
Post by: Fairlane514 on March 20, 2013, 10:19:42 pm

Quadrajet?     Check your float level.

Title: Re: Starting hot 1986 305
Post by: bd on March 20, 2013, 10:56:59 pm

Jeff,
Vapor lock isn't an issue after sitting for an hour, even in hot climates. 

So, is it hard starting as in it cranks fine, but doesn't fire, or labored cranking, or...?

When was the last time you gave it a complete tune-up?  Have you checked the cap and rotor, especially in the area of the carbon button?

Title: Re: Starting hot 1986 305
Post by: Jeff86inMS on March 21, 2013, 06:17:52 am

I have not tried cranking it without pumping the gas, am I flooding it by pumping the pedal ?(we are only talking three or four pumps of the pedal).  The temp here in MS is around low 70's (high), cooler in the AM, when it cranks fine.  Yes, it is a quadrajet, of which I know nothing about.  At the times when the issue occurs, it turns over fine, just doesn't fire off.  I can't say when the last tune up was, as I bought the truck used about a year ago.  I did pull a couple of plugs and didn't see any unusual wear.  I have not pulled the distributor cap or rotor.  Should I start with a complete tune up?

Title: Re: Starting hot 1986 305
Post by: Fairlane514 on March 21, 2013, 06:39:38 am

If it starts fine cold and then hard when its warm/hot it can be attributed to float level in your carburetor, its probably too high. If when you first got the truck it did not do this, its also possible the float has become fuel soaked so it doesn't rise up to shut off fuel flow.

I would do a tune up and a rebuild of your quadrajet, especially if its not been done in a while. There are books out there on how to rebuild a quadrajet if you want to save some money.

Title: Re: Starting hot 1986 305
Post by: Jeff86inMS on March 22, 2013, 06:01:25 am

Thanks all for the replies!  Fairlane, I will go ahead with the tune-up and look into the carb rebuild.  I'll let you know how it turns out.  Thanks again for the advice, much appreciated.!

Jeff

Title: Re: Starting hot 1986 305
Post by: Stewart G Griffin on March 25, 2013, 09:24:21 am

What is your starting proceedure cold engine?

What is your starting proceedure warm engine?