2F Emissions Trouble!

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Dec 11, 2007
I Recently bought a 1975 40 series cruiser. It is yet to see a trail or even pass emissions. It has a 2F that has been stripped of emissions stuff. (smog pump, all the vac hoses...) I rebuilt the carb, have gone throught 3 sets of plugs and tried the HEI ignition that came with it AND a toyota ignition system. I have done numerous compression tests and none of the cylinders are below spec. The best that the cruiser has run, it blew 5000+ hydrocabons! holy @%$ the legal limit here is 650. I need advise on what to do to get this cruiser going. Some people are telling me i should try a new carb or hook up the emissions stuff, others say its new motor time. I am on a limited budget as i am going to school. I would be interested in buying a motor if anyone has one near or around utah. Any advice..??????? -Ian
Have your carb rebuilt by Jim C (FJ40Jim). Assuming your desmog is complete and not half assed you should be able to pass emissions. My 55 w/ complete desmog passed w/ flying colors after the carb was tuned and dialed in. You'll probably need a tune-up as well - it can be done.
So CO numbers are normal? Is it failing at idle or cruising speed?

High HC in the absence of high CO is typically due to lack of combustion. Given the fact that the compression is good, this leaves misfiring as the prime suspect. Misfiring could be ignition (bad plugs, plug wires, dist cap, coil, etc) or it could be due to lean condition (in which case it would run poorly under load, bucking and spitting back through the carb).

If CO is also high, the carb could be extremely rich leading to unburned HC.

The smog stuff that came on the cruiser had very little to do with HC reduction, so putting it back on won't help much.
When I was a kid, a friend's dad who was master mechanic taught me this:

Always start with the basics.

In your case, if the motor has something wrong with it, it's not going to run good enough to pass smog no matter how well you get the carb and ignition set up.

What does the vacuum look like? F and 2F motors are prone to burning valves due to vacuum leaks. If you have some valve problems or bad rings, these are going to come up on a vacuum test. It also amazes me how many I see with badly adjusted valves, bad timing, worn out carbs and such, however if it's WORN OUT, you can't fix that by making adjustments.

I'd do this. It's awesome that your working on your own truck, I was student 20 years ago doing the same thing. For this problem, find a OLD mechanic in your area who's been around for ever (like the almightly pinhead) and pay him to diagnose the problem for you. Does not need to be a Land Cruiser mechanic, any oldschool and pre-fool infection (efi - computer) wrench will do. Hint, these guys like donuts and beer, some will kill for a good cigar. Sometimes you can find a younger guy with a lot of race car tuning experience, they are great too if you can find one.

Have him do some diagnostics on a 4 gas machine, run a vacuum test and maybe double check the work you've done. Listen to what he tells you and take it from there.

I once decided to mess with the Kugelfischer mechanical fuel injection on my old BMW and was screwed until I found a guy who could get it working again so I was once in the same boat. There was nothing wrong with the car except for all of the "adjustments" I made. Finding the right guy to fix it and $100 bucks poorer, the car was perfect so I quickly sold it.

You may have a tired old motor and there also be something that you are missing that is a relatively easy fix. I was once in a situation similar to yours that was caused by a bad timing light.

Of course, this plan impinges on finding a good, honest and highly skilled mechanic who is willing to help you out. Ask around, there is always one in every town. I've found the the Snap-On guy is a good source for local guru's. They tend to get around and get to know everyone.

If you want to have a go on your own, get a vacuum gauge from sears and do some google searching on how to do that. Here is a page for starters:

On Fire

Good luck,


P.S. Your 75 is highly sought after in CA as they don't need to pass smog. If you give up, sell it here or trade for a 76 or newer that runs better than yours.
I have done numerous compression tests and none of the cylinders are below spec. Some people are telling me i should try a new carb or hook up the emissions stuff, others say its new motor time. I would be interested in buying a motor if anyone has one near or around utah. Any advice?
If the compression is good, then it's not new engine time.
Whatever issues exist, they are external to the longblock.
Since 2 different ignitions were tried, it's likely fuel related.

PS: When/How did Stumbaugh materialize in LA-LA land?:)
Here there Jim,

I've been out here in LA for the last 8 months. Relocation. The weather is nice out here, but I sure do miss Virginia and Appalachia in general.

I agree about the compression. If he has good compression, then it's likely a carb or tuning problem . I've just seen so many situations where a problem like this goes on and on because of something that is missed and another set of eyes spots it straight away. I'd also verify all of the test results if I looked at it myself. Old wise men like you Jim come in really handy when there is a problem no one else can fix.

Along that same thinking, he rebuilt the carb, but I'd bet a few donuts and a cup of coffee that if he sent the Carb to you or Mark A. that this problem might just very well go away. I hate to go parts swapping, but just because it's rebuilt does not mean it's right, just like someone elses troubleshooting should always be verified...

I've always told folks that if they had their carb rebuilt by you or Mark that it would be a good investment, even if they were not sure they needed it. Odds are, the truck is going to run better.

I once had a really hard time with an F motor because I had a bad timing light and a bad compression gauge. The compression gauge read low when cross checked and the timing light was waaay too retarded when checked. Don't get me started about torque wrenches either...cheap tools suck and this was all Crapsman stuff. Moral of the story, check your diagnostic tools. Especially if they are old hand me downs.

Any advice..??????? -Ian

Tell us more about what all the emission numbers are under what circumstances and tell us how it runs (or how poorly it runs) under different circumstances.

PS Stumbaugh has seen the light. Even though we have our own burdens to bear in So Cal, at least the weather is great most of the time and we have beaches and lots of rocky trails to climb.
When i first got it, it bucked and ran horrible, first IM. test it blew 16681 HC (limit is 650) and 1.8 CO (limit is 4.00) that was on the Idle test @ 884 RPM. On the High Speed Test it blew 6917 HC and 8.54 CO @ 2350 RPM. After that, I tired to rebuild the carb myself. i just cleaned it the best i could and put a new needle and seat in it and all the new gaskets from the kit i bought. After that i took it in for a test again from a simple gas anylizer @ school and i don't remember the exact results but i was able to drop it to like 3000 or near that figure but the cruiser was barely running. During the test, I did my best to tweak the timing and fuel mixture screw on the carb in attempt to get it lower. After that i tried putting a toyota ignition on it, and got it to run for a few minutes but havent had success since. I really appreciate all the good advice and options from everyone. I pulled my carb earlier today and hope to have someone look at it soon. When i pulled it, I found a small lake (no exaggeration) of gas in the intake manifold ! It was as if the fuel just bypassed the carb and dumped into it. If someone is interested in rebuilding my carb, can I have a rough estimate of what I'm looking at and where you are located?
Sounds like you need a carb rebuild by a Land Cruiser carb specialist....this is something that you don't let anyone do unless they have done it before.

PM either 65swb45 (Mark A.) or FJ40Jim (who posted on this thread FJ40JIM@aol.com ? ).

Both have great reputations and both will do a great job. You will not be disappointed.

Bucking and spitting back through the carb are classic signs of lean condition misfiring. If it was a rich condition (aka "loading up") you would expect it to also fail CO specs. You might be due for a proper rebuild, but I would rule out all potential ignition problems first, such as a bad power feed from the key or bad plug and coil wires. To check the power feed, run a jumper wire from the battery + directly to the coil + and see if the problem goes away. If so, the power feed isn't putting out.
Pick the low hanging fruit first.
Pick the low hanging fruit first.
Good point!

I suspect there is a vac routing problem, perhaps in addition to carb issues. Post up some pics of the carb/manifold & vac lines connected to it. also, a pic of the dissy so we can see the vac line(s) connected to it.

Getting the hoses routed more correctly could alleviate issues w/ power valve and AAP and ignition timing...
Ok, looks like you live in Provo, UT. As I researched it, in order to have a vehicle that is smog exempt, you're looking to own a 67 and older. Utah is unique in that it requires smog checks only in the counties that are the worse offenders. I've heard recent rumors from DMV employees here in California that the new California smog exemptions have now included 1977 models.
Y'know, dude, you're getting some really good advice from the big guns.
To recap, start basic. Don't go off the deep end looking for another engine.
If Jim thinks it's vacuum start there. But if you need to pass smog don't quit there.
Do a complete tune-up. adjust the valves twice. Fix your ignition problem.
You may want to re-build your carb again and go a little deeper this time. The puddle of gas in your intake manifold should not be there. The stock carb is simple but it's easy to lose a little ball or put them in the wrong hole...and where's the fuel level in the porthole glass? I usually bought 2 or 3 re-build kits when I could find them for a good price...before I started going to the pro.
I fell into that "lean idle miss" mistake once. Thought that leaning out the idle mixture would drop my HC. Didn't work that way. The straight six seems to tolerate a rich mixture much better than a lean mixture.
As far as the puddle of gas goes, it may be leaking when it sits overnight. While it is conceivable that gas could siphon out one of the idle/transition circuits, the design makes this unlikely. I had a carb that leaked like this and I never could figure out why. I just got a different one that doesn't do it.

I don't think that this is a part of your misfiring problem. If it was dumping gas inappropriately, it would be a rich mixture and CO would be well above 4%. Since CO is low, it is either an electrical or lean condition misfire.
I Appreciate all the good information and advice. Right now i'm waiting to have my carb rebuild by Jim C, hoping for some good results. I'm also going to try to post some pictures later of the vaccume lines, although there aren't many especially ones going to the carb.

Money well spent. You won't be dissapointed.

I learned early on with this hobby is that if you are going to do the work yourself there is no point trying to skimp on parts and tools. If it's not broken then don't fix it but when it is busted then don't cheap out. Another key point when any DIY project is decided what to rebuild and what to leave to the Guru's. If your a Pinhead caliber of guy, rebuilt it yourself. For the rest of us, Mark and Jim the carb guy's.

Even if your your not certain that your carb is the root cause of your fault I am sure that a good rebuild will be a great added value to your truck's overall driveability and not wasted money at all. Other parts tend to work until they fail where old carbs and distributors still work but not so well. Also, I have found that problems are often caused by one bad part but sometimes a combination of them. A truck that would run so so with a worn out distributor is going to run really badly with a worn out carb and distributer. Throw in a host of other mildy warn parts and it all ads up. I tend to err on the side of caution and replace stuff long before it gives me trouble even if a good used part is all I have. My dad worked on airplanes, maybe I learned that from him.

Keep us posted on happens and good luck with the fix.

I certainly don't claim to have any particular experience with Aisan carbs. I'm more of a Solex/Rochester/Carter guy.

My '76 Aisan started failing smog checks with dribbling fuel out of the main jet at idle and fuel leaking from the bowl into the intake overnight. I rebuilt it twice and tried swapping parts from other carbs, but I could never get it to pass smog. It ran fine, but it would run really rich at idle. If anyone has any insight into what would make it do these things, I would like to hear it.

Sometimes it is better to admit defeat and either get a new carb or let the professionals deal with it.

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