Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Choke issue on quadrajet


Recommended Posts

Im having issue with my 1990 Malibu Euro F3. It has a 350 in it with a divorced choke quadrajet  I was having issues with my choke so I replaced it ran it for awhile but It wasn't fully closing on cold starts I would have to hold the choke shut until warm. I started comparing the 2 chokes and the new loop on the bi metal spring sat higher than the original.  So i put the original back on that fixed my cold start issue. However now once the motor warms up it runs like crap and will occasionally backfire out the carb. If I hold the choke closed I slight bit it runs exactly how it should. Is it possible that the choke is opening to far or more likely the spring in the choke loosening up to much or another issue.  I am also 3 1/4 turns ou on fuel air mixture screws

any help is greatly appreciated

Link to post

I believe you have issues deeper in the carb.  On my carbureted boats, I removed the choke.  You don't really need it to start an engine when the air temp 80 degrees.  Once the engine is lit and running for a couple minutes, the choke should be wide open and not needed.

 

Link to post

Could this be caused by a float issue or needle and seat?   

I'm not much help with carbs just trying to learn something.  

Link to post
19 minutes ago, REW said:

Could this be caused by a float issue or needle and seat?   

I'm not much help with carbs just trying to learn something.  

Yes it could.

Holding the choke partially closed to make the engine run correctly indicates it's running lean.  A choke is a pretty crude feature on a carb, when it's (partially) closed it creates a vacuum below the choke plate, around the venturi.  This causes extra fuel to pulled though the carbs fuel metering system, causing it to go richer.  It's done to smooth out an engine when it's cold, think starting a car when it's 20 degrees out.

Since it fixes the problem, either float level too low, or a restriction in the fuel metering system. 

Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...