Fj-40 tuning issues

beaverlj

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Jun 23, 2026
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I just bought a 1963 fj-40 off of Facebook marketplace. It was not running when I got it and had a new carb on it with no brand. I got the car running and idling well and the timing set to 7 btdc. Whenever I give it gas or when it’s under load it starts sharply popping out of the exhaust. I thought maybe the mechanical advance wasn’t working but after taking the distributor apart I can’t really tell. It does move but doesn’t really spring back like other distributors I’ve seen. I don’t know if I’m on the right track with timing or not.
 

AdamKFarmer

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Denver, Co
I just bought a 1963 fj-40 off of Facebook marketplace. It was not running when I got it and had a new carb on it with no brand. I got the car running and idling well and the timing set to 7 btdc. Whenever I give it gas or when it’s under load it starts sharply popping out of the exhaust. I thought maybe the mechanical advance wasn’t working but after taking the distributor apart I can’t really tell. It does move but doesn’t really spring back like other distributors I’ve seen. I don’t know if I’m on the right track with timing or not.
Post some pictures of your mystery carb. Have you walked through the fsm timing procedure?
 

Rzeppa

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Make sure the points have adequate gap, 0.018". Points not opening enough can cause that observation. Also, at our elevation you need more than 7° BTDC. 11° is a typical setting here.
 

J1000

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To me that sounds like it's running lean under load, try adjusting the carb to give more fuel.
 

Rzeppa

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To me that sounds like it's running lean under load, try adjusting the carb to give more fuel.

The only mixture adjustment on the stock Aisin carb is the idle mixture. To change the mixture at higher throttle settings requires rejetting it.
 

beaverlj

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IMG_2118.jpeg

IMG_2119.jpeg
This is the new carb that was on when I bought it it also came with a Holley carb that looked nearly identical that was on it previously. I am going to set the timing more advanced tomorrow. Does anyone know anything about the small dial that sits on the shaft of the distributor?
 

Rzeppa

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My '71 40 had a Holley when I bought it in 1998. It ran good on the highway, got crappy fuel economy and scared the crap out of me when I took it off road (would cut out just when you needed it off camber or on up or down slopes). I got a stock Jim C. Aisin and have been so happy going back to stock! Since your new find is a 1963 you don't have to deal with the smog police you can do whatever you like.

My recollection of the dial on those dizzys is that would set the static timing somehow. I never had one of those and I have a LOT of dizzy's in my dizzy box and don't have any with that but I have peered under hundreds of Land Cruisers over the years and know I have seen those dials.
 

Rzeppa

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It should look kinda like this…emphasis on kinda… this is my spare 60 carb.

The stock carb for a '63 is single barrel IIRC. It's also going to be super simple as that was before any kind of emission controls.
 
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