1975 2f FJ40 with 80-87 Aisin Carburetor Advice Needed

[saltfever]

My 1975 FJ40 came desmoged with a Weber carburetor installed and what I thought was a factory Aisin carburetor. The Aisin is between 8/80 - 8/87 per the Spector off-road carburetor identifier. I rebuilt the Aisin and installed it and now having a problem I can’t seem to fix so I’m asking for advice.

The carburetor seems to idle fine, revs up fine, but when driving sputters under a load and has no power. I’ve plugged all of the vacuum ports and connected the vacuum advance from the distributor to a port near the idle mixture screw. The distributor vacuum advance worked with the Weber so I know that works...checked with a timing light. No other vacuum lines are attached to the carburetor. I’m thinking I don‘t have the vacuum lines hooked up properly or the carburetor won’t work on a 1975 model. Any advice is really appreciated. Thanks

 

[MDH33]

Post some pics of the aisin installed. Sounds like something isn't connected properly.

Did you rebuild it yourself and are certain all passages are clear and everything was reassembled properly?

 

[4Cruisers]

What distributor do you have (a photo or two would help)? What's your FJ40's production date?

Here's a diagram with the FJ60 vacuum ports:

 

[saltfever]

I rebuilt the carbu myself and confirmed no blockage. Attached are a few Photos of the carburetor and the distributor. IGNORE THE FUEL LINE...it’s temporary to get it started while I fabricate a new hard line before hitting the road.

 

[4Cruisers]

That's the correct port to the distributor, but you have the original vacuum retard distributor. You have a couple of options: 1) cap the vacuum nipples at the distributor and at the carburetor (the distributor can do fine with only mechanical advance), or 2) replace the vacuum retard unit with a vacuum advance unit. I've been selling new NipponDenso advancers that will fit your distributor, I may have a few left.

 

[saltfever]

4Cruisers, thanks for the information. Do the other vacuum ports look correct...line connections and capped off? It appears the linkage is not be functioning properly as the secondary butterfly toward the bottom of the carburetor don’t open when wide open...not with the engine running. Is there a resource you could point me to for some photos of the correct linkage attached?

 

[4Cruisers]

To continue to clean things up, 3, 4, 6, and 7 could be capped, just like you've done for 8 and 10. 3 is for high altitude compensation, which you don't have, 4 is for exhaust gas recirculation which you don't have, and 6 and 7 are just extra manifold vacuum ports. I'm not sure about the rest, I'll have to look at some diagrams.

 

[Spike Strip]

As long as ported vacuum is attached to the vac retard distributor, it's going to retard spark just when you need it to advance... i.e. no power ... 4Cruisers knows of what he speaks.

Toyota (and vendors) still sell a brand new Denso Vac Advance (no smog) dissy.

 

[saltfever]

Thanks for the advice. I do have a few other questions...should the choke opener be attached to a vacuum port? My current setup doesn’t allow the choke to move...nothIing is attached so it moves freely and is only adjustable via the choke cable from the dash. It starts up when I close the choke but won’t run when the choke is opened either on a cold engine or a hot engine. I‘m wondering if the choke opener is something to do with that. Thanks in advance.

 

[samatulich]

My understanding is that the choke breaker/opener needs to be hooked up to vacuum. As soon as the engine fires, the coke breaker opens the choke just enough to keep it running. Do you have a capped vacuum port available? If I recall, mine is hooked up to the manifold vacuum port.
someone correct me if I’m wrong.

 

[samatulich]

Here’s a pic

 

[saltfever]

Thanks. I’ll try that.

 

[Pin_Head]

You didn’t really describe the problem in enough detail to offer any informed suggestions as to how to fix it. You need to describe what you mean by “sputters” and “no power” in detail and especially the circumstances when you are having these problems. What is the throttle position? Wide open? Choke on or off? RPM? Load on engine? Going uphill in 4th gear?

For the distributor, you just have to fine the advance setting that gives you the best performance without pinging or knock under high load,, like going up hill in 4th gear with WOT. Disconnect any vacuum lines To the distributor.

Other than that check for the usual problems, like manifold vacuum leaks, lack of idle fuel and if the secondary is opening at WOT.

 

[saltfever]

Finally determined the issue with vacuum. I had a cracked intake manifold. Once repaired all is good.

 

[EWheeler]

Finally determined the issue with vacuum. I had a cracked intake manifold. Once repaired all is good.

Just curious, how did you narrow it down to the manifold, and where was it cracked? Always good to hear back from OP's on solutions to problems.

 

[saltfever]

Took it to a local Fj40 specialist. He found an exhaust leak at the mainfold gasket. When he took it apart the intake manifold was cracked under the carb. He sent it to a machine shop that welded it up then decked the exhaust and intake manifold. All put back together and runs fine.