Not running right
Thread Starter
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Senior User
Joined: Dec 2007
Posts: 118
Likes: 1
From: Colorado
Not running right
My '77 F250, 460 all of a sudden decided it doesn't want to run right. I just drove it last week, ran fine. Went to start it today and it sounds like it's missing at any RPM. Checked for vacuum leaks, fuel filter, carb, timing fuel pressure..it's all good. The motor is pretty old and will be rebuilt in a few months but is a blown head gasket possible? It won't even idle so I can't watch the tail pipes. Will do a compression test tomorrow.
Post Fiend
Joined: Jul 2006
Posts: 6,948
Likes: 44
Did you check the float level?
Carbs that sit for a while can lose some float adjustment, and if the carb bowl is too full, it will foul plugs, and start killing cylinders.
If this is not ingnition related, like a bad ingition module, then it leads me to believe that it is carb related.
Carbs that sit for a while can lose some float adjustment, and if the carb bowl is too full, it will foul plugs, and start killing cylinders.
If this is not ingnition related, like a bad ingition module, then it leads me to believe that it is carb related.
Elder User
Joined: Jan 2004
Posts: 887
Likes: 0
From: Colorado
Does it smell like anything was added to the fuel?
Did you make sure your PCV hose, and power brake booster hoses are attached properly? I know sometimes i knock those hoses off the fittings, get in my truck to start it, and it wont idle, so i usually rev it up a little, and its popping, then i remember to check those 2 hoses.
The reason i ask about the fuel is because the night before the last race of the season this year, my truck started acting funny, was running like junk, wouldnt idle, etc.. I pulled a plug and it smelled like the stuff they stain floors with. I had to stay up the next 6 hours driving the truck, adding gas every 40-50 miles to get all of the nasty fuel out. Then had to go home, change the plugs, re-build the carb (did that at the track) and swap in a clean fuel filter.
Did you make sure your PCV hose, and power brake booster hoses are attached properly? I know sometimes i knock those hoses off the fittings, get in my truck to start it, and it wont idle, so i usually rev it up a little, and its popping, then i remember to check those 2 hoses.
The reason i ask about the fuel is because the night before the last race of the season this year, my truck started acting funny, was running like junk, wouldnt idle, etc.. I pulled a plug and it smelled like the stuff they stain floors with. I had to stay up the next 6 hours driving the truck, adding gas every 40-50 miles to get all of the nasty fuel out. Then had to go home, change the plugs, re-build the carb (did that at the track) and swap in a clean fuel filter.
Postmaster
Joined: Aug 2005
Posts: 2,760
Likes: 8
From: Gadsden Purchase
Colo79Ford wrote:
> Does it smell like anything was added to the fuel?
Yeah. :)
Or what about water in the fuel bowl?
It forms a clear jelly like stuff that can't really be seen until
you go and pour the fuel out.
BTDT
Of course a little bit of water is very hap-hazard in it's action.
Alvin in AZ
> Does it smell like anything was added to the fuel?
Yeah. :)
Or what about water in the fuel bowl?
It forms a clear jelly like stuff that can't really be seen until
you go and pour the fuel out.
BTDT
Of course a little bit of water is very hap-hazard in it's action.
Alvin in AZ
Thread Starter
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Senior User
Joined: Dec 2007
Posts: 118
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From: Colorado
I will post what the compression comes out to. I'm in the Denver area, so I'm not expecting much more than 100-110 psi with a good motor at this elevation. I will vacuum check it too, will have to have the wife keep her foot on the gas to keep it running. The fuel smells normal. Last check will be the carb, it has an Edelbrock 750 on it. Thanks for the pointers so far.
Posting Guru
Joined: Nov 2004
Posts: 1,628
Likes: 0
From: Northeast Nebraska
If the gas was nasty and old it will run fine but once you shut it off that sticky stuff can keep a valve from closing. Im interested in hearing how the compression test comes out.
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Thread Starter
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Senior User
Joined: Dec 2007
Posts: 118
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From: Colorado
Well, I took everyones advice and checked into the fuel first. I did fill it up the last time I drove it so it made sense. I ran a fuel line right out of a 5 gal can I use for my quad to the fuel pump. Within 2 - 3 minutes she started running good again. I put everything back and drove her around, she ran but not happily. I will drain the tank and never use that station again. I know the engine is tired, so I am installing a semi modified long block 460 in December. Thanks again for all the input.....
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