Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: CookesForChrist on April 20, 2020, 11:55:51 AM

Title: Hesitates on Acceleration from Stop - 1985 Cougar 3.8L Carb
Post by: CookesForChrist on April 20, 2020, 11:55:51 AM
1985 Cougar 3.8L Carb

I just got my "new" Cougar with 73,000 kms. It's in beautiful shape overall. However, when it starts up from cold, it idles rough. Also, when I accelerate from a stop, unless  I gun it, it almost always hesitates and seems like it wants to stall.

Any ideas on what could be causing this? I'm new to this forum and would really appreciate your help!

God Bless.
David
Title: Re: Hesitates on Acceleration from Stop - 1985 Cougar 3.8L Carb
Post by: softtouch on April 20, 2020, 05:30:46 PM
Is this a Canadian car that came stock with a carb?
Title: Re: Hesitates on Acceleration from Stop - 1985 Cougar 3.8L Carb
Post by: softtouch on April 21, 2020, 03:03:35 PM
1985 3.8 V6 cars built for sale in Canada came with a carb.
Those built for sale in the US came with CFI (Central Fuel Injection)
The CFI unit can be mistaken for a carb by those not familiar with it.
Title: Re: Hesitates on Acceleration from Stop - 1985 Cougar 3.8L Carb
Post by: CookesForChrist on May 10, 2020, 07:07:33 PM
It is definitely a carb.

Doing some research, people are saying this could be the accelerator pump on the carb or the power valve. I opened up the carb and the accelerator looks good, so I'm thinking it's the power valve. I am planning to rebuild the entire carb and see what that does. Hopefully it works!
Title: Re: Hesitates on Acceleration from Stop - 1985 Cougar 3.8L Carb
Post by: jcassity on June 29, 2020, 08:12:28 AM
my first gut is agreeing with your advice you have but you can also while there do this...........

with a bone cold motor, loosen the three screws on the auto choke pull off.
rotate the the housing until you just barely see the butterflies crack open
now tighten the screws.
Title: Re: Hesitates on Acceleration from Stop - 1985 Cougar 3.8L Carb
Post by: CookesForChrist on June 29, 2020, 09:43:53 AM
Well, a few weeks ago, I decided to bite the bullet and rebuild the whole carburetor, which included replacing the power valve and replacing the normal power valve gasket with a viton gasket. That definitely did the trick. No more hesitation - even after driving over 1,000 kms! Praise God. Thanks to everyone for your suggestions and advice!

P.S. This video talks about the use of a viton gasket - https://www.youtube.com/watch?v=iHHhrKv5mCc