Fj-40 tuning issues

beaverlj

Brand New
Joined
Jun 23, 2026
Messages
3
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

Hard Core 4+
Joined
Aug 29, 2011
Messages
676
Location
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

Rising Sun Member
Joined
Aug 24, 2005
Messages
9,019
Location
Kittredge CO, USA
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

Rising Sun Member
Joined
Oct 11, 2018
Messages
1,917
Location
Morrison, CO
To me that sounds like it's running lean under load, try adjusting the carb to give more fuel.
 

Rzeppa

Rising Sun Member
Joined
Aug 24, 2005
Messages
9,019
Location
Kittredge CO, USA
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

Brand New
Joined
Jun 23, 2026
Messages
3
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

Rising Sun Member
Joined
Aug 24, 2005
Messages
9,019
Location
Kittredge CO, USA
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

Rising Sun Member
Joined
Aug 24, 2005
Messages
9,019
Location
Kittredge CO, USA
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.
 

74fj40

Hard Core 4+
Joined
Oct 6, 2005
Messages
1,392
Location
Castle Rock, CO
That’s a holley 2300 copy. Lots of people run those with success but an aisin carb will be better. Sounds like a timing issue for sure.
 

Rlong

New-ish
Joined
Nov 4, 2010
Messages
11
Location
Fort Collins
The correct SD single barrel is a rarity, on mud people ask between $500 and $1,000 in original /needs rebuilt condition. I have one I took off my 63’ fj45 to run a holley 350cfm when i was younger. (It will stay with the truck) Tuned right the Holley ran well. That may be a 500 cfm (far more common) Holley clone which might be a little hard to tune and tend lean (i.e. too much “air”).
Where are you located?
 

unimogguy

Rising Sun Member
Joined
May 10, 2022
Messages
389
Location
Wheat Ridge, CO
Agreed I’d get a SD40 carb and either send it off to Jim C. or rebuild it yourself.

Here’s a SD40 rebuild kit:

As far as I’m aware they are the only seller of the SD40 rebuild kit currently.
 

Crash

Rising Sun Member
Joined
Aug 23, 2005
Messages
4,845
Location
Denver
FWIW I bought a pretty pristine ‘67 40 in ‘73 from Stevinson Toyota when it was located at W 7th Ave. and Wadsworth. Memory says it was clean, low mileage and straight as an arrow. I didn’t know jack about Cruisers at the time but it ran great and was ultra reliable until I tried wheeling some serious off-camber trails above Frisco in Summit Co. It would flood to the point of not running at all and it once left itself stranded for seven days on Meadow Creek trail because of this fault. I had a mechanically inclined friend and, once we got the truck off the hillside, we took a look at the carburetor. Turned out to be a single barrel Holley and when taking it apart we found a piece of a Budweiser can that had been formed into a baffle of sorts which, obviously, didn’t work for the intended purpose. Carefully put it all back together and sold the truck, because I could tell that wheeling old miners trails was something that needed to be explored. Bought a ‘70 factory soft top and wheeled the snot out of it before the Forest Service began gating trails such as Eccles Pass above the Eagles Nest Wilderness area above Silverthorne and French Pass that connects Breckenridge and Como. Both incredibly beautiful. The ‘70 had the stock Aisin that never had a problem with t(r)ippy trails. Anyway…
 

Rzeppa

Rising Sun Member
Joined
Aug 24, 2005
Messages
9,019
Location
Kittredge CO, USA
My 1971 FJ40 had a Holley in it when I bought it. Ran like a banshee on the highway but off camber or in inclines would sputter and die just when you needed it. I put a Jim C. stock carb on there and instantly got better fuel economy plus the ability to drive anywhere no matter the incline or angle.
 

wesintl

Moderator
Joined
Aug 22, 2005
Messages
8,985
Location
in da house
while if could be timing my exp is it's usually exhaust/vacuum leaks with rich mixture. Exhaust leaks allow oxygen into the system and the unburned fuel gets to do it's thing
 
Back
Top