New 40 owner.

[MEMCruiser]

I just purchased a 40 that seems to have some carb problems. It has a weber 32/36 carb. It was having backfire (through the carb) problems right after buying it and driving home. It was very sluggish to accelerate also and would only do about 45 mph.

As soon as I got home I sent it to a shop and had them rebuild carb. Mechanic said that the choke spring was kind of weak and might need replacing. Also said first stage jets might need enlarging. It seems to run a little better but sometimes does not start or idle very well. It also seems to have a small back fire through tailpipe that is noticeable when letting off accelerator. It pops a few times either in gear and decelerating or when not in gear and getting off the gas.

The PO had a rebuilt aisin carb that was included in the purchase. I am trying to figure out if I should make the jump to the aisin or if after the weber rebuild maybe it is not a carb problem. Also has a rotary knob fuel regulator which I am not sure how to adjust to make it lean or rich. Are larger numbers making fuel more rich? Is a back fire a rich or lean problem. Looking on the internets I see where some say rich and some say lean caused back fires.

If I do make the jump to the aisin how can I determine what OEM parts I need to get back to that set up?

I also am not opposed to doing and EFI kit if I think it will clear up my problems.

I am a complete newb when it comes to working on cars, especially carbs. Assume I know nothing!

Thanks for the help.

 

[Eshu Elegua]

not sure if you are a newbie with 2,264 post's ...but as you know pics are mandatory..i will change to the Aisin carb

 

[MEMCruiser]

not sure if you are a newbie with 2,264 post's ...but as you know pics are mandatory..i will change to the Aisin carb

I have had a 100 that has been sold so I know how to order floormats, install ARBs but that is about it. Have not driven a carb since I drove a 74 VW and have tons to learn about carbs and 40s. Most of those posts are BS posts in local club with a few 100 tech.







Here is pic of accel pedal and where cable attaches to carb. Does this need to be changed out for switch to aisin carb?

 

[pavieSD]

What the heck is that black tube running next to your throttle cable??? It's been rubbing on the cable for awhile. so at a minimum you'll want to move it away from that location. Doesn't appear to be a stock FJ40 part.

As to your question, you should not have to change the throttle linkage when switching carbs since they are pretty much all in the same location. You may need to adjust the cable to get the max throttle opening at WOT, but that should be easily done after installing whichever carb you go with. If you're having trouble with the current carb, the best bet might be to have the Aisan rebuilt now, then swap it over when you get it back. That way you'll know that you're running a good carb and can take that out of the equation when diagnosing any issues.

 

[jimkyser]

My guess is that the black cable is for his parking brake.

 

[Eshu Elegua]

if the Aisin carb have the linkage system,then,you have to source all the parts, post a pic of the carb so we can check or someone else will chime more inf, nice 40 BTW....and change that pedal syst. also

 

[MEMCruiser]

Current carb






Aisin carb supposedly rebuilt according to PPO.









MISC parts.

 

[MEMCruiser]

Can't change pedal or E brake cable placement. Looks stock can somebody post pic of their 40 to compare?





Previously mentioned fuel regulator.





Is 1 lean and 5 rich?

 

[DomsFJ40]

Can't change pedal or E brake cable placement. Looks stock can somebody post pic of their 40 to compare?



View attachment 641555

Previously mentioned fuel regulator.



View attachment 641556



Is 1 lean and 5 rich?

I had one of those on a '67 mustang when I was running a holly blue pump, eletric fuel pump. Are you running a eletric fuel pump?

 

[Eshu Elegua]

looks that the Aisin carb it's the linkage type, but missing the wires for the idle solenoid will be a pita, needs ignition 12 v to keep the carb at low rpm..check the manual book for more inf,

 

[JohnnyC]

increase your fuel pressure to 3lbs and report back after a test drive

 

[MEMCruiser]

I had one of those on a '67 mustang when I was running a holly blue pump, eletric fuel pump. Are you running a eletric fuel pump?

No. PO changed from an electronic to a factory type mechanical. I wonder if it would run better with an electric fuel pump if I stick with the weber carb.

 

[MEMCruiser]

looks that the Aisin carb it's the linkage type, but missing the wires for the idle solenoid will be a pita, needs ignition 12 v to keep the carb at low rpm..check the manual book for more inf,

I wonder if it would be easier to go ahead and install a fuel injection kit.

I was trying to figure out why the last two owners just did not put on the aisan carb if it was a sure fix but now
I understand why they did not.

 

[Bruzzi]

I would leave the factory mechanical pump and get rid of the regulator, it's not needed with the factory pump. In my experiences the electric pumps are unreliable.

 

[MEMCruiser]

increase your fuel pressure to 3lbs and report back after a test drive

it has been on 3 most of the time that I have been running it

Can the fuel regulator increase pressure? I am assuming all it can do is decrease the pressure from the
mechanical fuel pump.

 

[JohnnyC]

it decreases to the pressure you dial into it....three is where most people run the PR on the webers

how many turns out is the idle mixture screw?

what size jets are in the carb?

 

[MEMCruiser]

Those are good questions. PO never told me and just drove it to get stuff at store so never really tore into carb.

Mechanic who did rebuild said first stage jets might be too small. Is there anyway you can tell the size of jets without

taking apart carb? If you do have to take it apart which part is removed, partial or all?

 

[YotaJosh]

How's the ignition timing?

I noticed in the PO for sale ad, there was a new fancy dizzy installed at some time. Are you confident that this was timed right when it was put in?

BTW - it was nice to meet you at Superlift this past Saturday. If you were closer to Little Rock, I'd be glad to help you troubleshoot these issues.

 

[MEMCruiser]

How's the ignition timing?

I noticed in the PO for sale ad, there was a new fancy dizzy installed at some time. Are you confident that this was timed right when it was put in?

BTW - it was nice to meet you at Superlift this past Saturday. If you were closer to Little Rock, I'd be glad to help you troubleshoot these issues.

Nice to meet you too Yotajosh .

Not sure of PO ability at timing. Think he had some knowledgable help. It's 2 days since carb rebuild and it's starting to backfire again, through carb and tail pipe. Thing runs good at speed but languishes getting there. Guy who did carb rebuild said might need valve job.

Running fuel regulator at 4 since 3 was sluggish.

 

[MEMCruiser]

Took 40 to a carb guy who determined that it's sucking air where carb sits on motor. There is also a plate there stuck between. Would these gaskets be a TOYO part or weber?

He sprayed brake cleaner in this area and motor would almost stall.