Will this work??

[raymond2335]

I just finished assembling a 1978 2f engine and installed it into the truck. (complete rebuild) The carb was seized up, full of acorns and in pitiful shape. I rebuilt it to the best of my abilities- I got the engine to fire but it runs horribly... coughing and backfiring, barely able to keep it running. I have a new Chinese carb that is identical EXCEPT my original has a return fuel line carrying unused fuel back to the tank???? The Chinese carb has none. What happens if I swap them out? The linkages are identical as well. I can cap the return line or delete it outright if this will work.

 

[vfrer]

You can do it. Don't need the return connected to the carb.

 

[jestlurnin]

Cap it and run it. Been running my 45 like that for 8 months

 

[samatulich]

Did you tune the rebuilt carb? Nothing will run correctly if not tuned. I'd start there. Otramm has a good YouTube video on tuning a Aisan carburetor.

 

[pb4ugo]

Idk, if it will work or not...

This might be helpful.

Thread 'Knockoff Aisin Carb'

Oct 25, 2025

Been wanting to do this for awhile and since I decided to desmog my project 60, seemed like the perfect opportunity to do a write up on the knockoff Aisin carbs. These carbs have a bad reputation but I find it’s mostly because they need a good cleaning and some minor work. These are a great option for someone missing a carb completely, or who has a Weber or something that wants to go back toward original. These are a great desmog carb because they only have 1 vacuum source. If they made one with a mechanical secondary that’d be even better!

I got this one off Amazon for about $58; it’s a...

• Skreddy
• Replies: 15
• Forum: 40- / 55-Series Tech

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[Skreddy]

You can drill and tap that carb for the return. The other way is running the later fuel pump with the return in the pump (60 series pump).
Capping the return, as said, has been done by many as well.

 

[raymond2335]

I just finished assembling a 1978 2f engine and installed it into the truck. (complete rebuild) The carb was seized up, full of acorns and in pitiful shape. I rebuilt it to the best of my abilities- I got the engine to fire but it runs horribly... coughing and backfiring, barely able to keep it running. I have a new Chinese carb that is identical EXCEPT my original has a return fuel line carrying unused fuel back to the tank???? The Chinese carb has none. What happens if I swap them out? The linkages are identical as well. I can cap the return line or delete it outright if this will work.

Thanks got the input. I’ll give a try after a thorough cleaning.

 

[brian]

I've read before that you don't want to be dicking with carb tuning on a fresh engine rebuild till it has seen some break in time.

 

[Pighead]

I got the engine to fire but it runs horribly... coughing and backfiring, barely able to keep it running.

You're sure it's a carb problem and not an ignition problem?

 

[rlong]

I've read before that you don't want to be dicking with carb tuning on a fresh engine rebuild till it has seen some break in time.

 

[rlong]

….if you don’t know what your doing.