1970 FJ40 carb? trouble (1 Viewer)

[espensen]

Hi!

I'm new here on mud, hopefully someone understand me, my English is not very good. But we'll try, i'm from norway btw.

I have bought a FJ40 resto project for ca 2 years ago. Now i'm trying to start the engine. I have rebuilt the carburetor with a carb kit from sor, new fuel lines, filter and cleaned the tank. New spark plugs, adjusted timing.
I've tried to adjust the carburetor right according to the Haynes manual.

The problem is : It starts easy, and idle smooth, but when i try to rew it up it just dies, if i'm very very careful with the throttle it's possible to rew it up slowly...

My first tought is that it get to much gas..

Any suggestion?

Here are some pic of the carburetor:

 

[Pin_Head]

Uffda! It is not likely to be too much fuel, but rather much more likely to be too little fuel. Does it spit back through the carb or backfire when it dies? Does the accelerator pump nozzle squirt fuel when you open the throttle? Are there any vacuum leaks? Is there any fuel dripping out of the primary main nozzle at idle? What is the manifold vacuum at idle?

The soft copper tube is bad practice for fuel line. They crack and leak due to vibration. Use steel tube.

Copper is really dangerous to use as brake lines for the same reason and for the reason that it won't hold up to high pressure.

 

[espensen]

Thanks for reply
There is no backfire or spiting.
The accellerator pump spray fuel.
I've checked carefully with startgas for leaks but couldn't find anything.
Can't see any dripping but there are wet around the prim main nozzle.
Haven't a vacuum meter right now, maybe i can get one the next week.

So cobber tube is no no? Hm maybe I have to change them then...


Here's a video:

 

[Pin_Head]

It may be time to go through the carb again and verify that all the tiny passages for gas and air are open. If there was too much gas you would see it pouring in.

 

[reddingcruiser]

X2 ^^ Copper tube is a no-no, ESPECIALLY for brake lines

 

[thebigredrocker]

Are you seeing a strong stream of fuel from the accelerator pump? On the video your accelerator pump doesn't appear to have much travel, could be just an optical illusion though. I had a big hesitation on acceleration on my 71 F, so I put 5 washers on top of the 71 Aisan pump arm, under the cotter pin and that seemed to give me a bigger fuel squirt. At rest the top of my plunger is 30mm from the flat surface on the airhorn. At full squirt it drops down to 24mm, so about a 6mm stroke is what I've got. I also switched to a leather plunger. If you have an old leather plunger you can soak it in oil to re-hydrate it. I would say my throttle respose is now really good.

Also, it appears like your float needs adjustment, as you probably know fuel level should be centered in sight glass.

Can you post a video of your engine at idle? Make sure it's warmed up good first. Your rpms sound high. Something sounds funky, not sure what it is.

You really need a vacuum gauge.

 

[espensen]

Thanks for replys evryone! Shall have a look at it the next week

 

[espensen]

Then I have opened the carb again and checked passages and holes, it looks good to me... I have adjusted the float so the Level is on center of glass. I've got a vacuum gauge, it measures about 19-20 in HG at idle.
thebigredrocker: I think i have about 6mm move on the acc. pump too. When I try it whithout the engine started it sprays well I think.


Heres a video when it idles...


Is a new carb the solution?

 

[Pin_Head]

The idle is great and the manifold vacuum looks good too. It sounds like there is no fuel in the transition slot (or off idle slot), which is just above the throttle plate in the primary bore. The purpose of this slot is to provide a little fuel just as the throttle plate opens so it revs up and does not bog down. It gets fuel from the idle circuit, but maybe there is not enough fuel to both idle well and fill the slot. Try putting a little fuel in a squirt bottle (not a spray bottle) and dribble fuel onto the throttle plate while you open the throttle and see if it transitions smoothly to high speed.

By the way, that is a great looking cruiser and it requires the original carb. Don't put the wrong carb on it. You also need to hook up the front brake circuit in the master cylinder too as this is a safety issue.

 

[thebigredrocker]

@65swb45 would be the guy to have rebuild your carb should you exhaust all other possible reasons for the hesitation. He would be one of the most helpful in troubleshooting also. I imagine he's swamped so I'll bounce some idea's that may or may not be helpful

I wouldn't give up on the Aisan carb yet. You've got the best carb for your engine. For some reason when you crack the throttle you are not getting enough fuel in relation to the newly introduced air.

What size is your main jet? 120 works great on mine.

Did you line your fuel tank with a coating or just clean it? Double check that you don't have fuel restriction in your new filter. If you have a screen under the bolt near the fuel inlet, check that too.

Shine a light in the #1 barrel, can you see fuel spray near the brass nozzle at idle? How about nozzle fuel spray when you crack the throttle.

What does your vacuum number drop to when you open the primary throttle plate?

Have you sprayed carb cleaner around the manifolds and carb base at idle? If you have a vac leak you will hear a slight increase in idle speed.

 

[thebigredrocker]

If your distributor is a candidate for Pertronix, that might eventually be worth considering. I definately felt like my F ran better after switching to Pertronix. You can run Pertronix with your OEM Nippondenso coil, just bypass the ballast resistor. Marksoffroad.net has some good info in his FAQ.

 

[tls3601]

Or @FJ40Jim either guy will get you going

 

[Pin_Head]

You can run Pertronix with your OEM Nippondenso coil, just bypass the ballast resistor.

Whether you need a ballast resistor or not depends solely on what type of coil you have and not on the distributor or ignitor. A BR type coil will run without a BR, but it will run hot and may burn out and fail

 

[espensen]

I've got another problem, one of the freezeplugs inside the valvecover has got a hole because of rust. SO I have to fix that before I go further.
According to previos owner , the engine was newly rebuild.... I think I'll pull of the head too and have a check.

 

[espensen]

Hello!
I finally got the engine back together. So I have looked into the carb again. I have adjusted it it a few times and it runs better now but not good enough. It runs great at idle and if i accelerate without driving it revs up fine (almost). But under load when starting to drive and changing gear, it hesitates off idle.. I have double checked with propane and a hose around the manifold, no vacuum leaks. After adjusting it idles at 19-20 in Hg.
And I don't think it is a fuel delivery problem because the fuel level in the bowl is steady when reving, and it runs good at higher rpm's and up hills. I run 120 main jets and 200 secondary.
I have also cleaned the passages for the idle circuit a couple times without any improvements. I have also tried to connect the solenoid directly to the battery, no change.

So I'm running out of suggestions. Could the main slow jet be too small? It is stock 50 size.

Any opinions for this? Carburetor Rebuilt 10/1969-9/1971 All Models [21100-60200-R] - $250.00 : CruiserParts.net, Toyota Landcruiser Parts

Because everyone love pics here's how it looks like now:

X2 ^^ Copper tube is a no-no, ESPECIALLY for brake lines

I've checked and this is not copper, It's copper nickel mix and is what we use here in Norway with great results.


Thank you all for the inputs!

 

[thebigredrocker]

Could it be a spark timing issue? Are you running the OEM vac retard distributor with points? If so, FJ40Jim recommends to cap the dissy vac line and advance timing to 10 BTDC.

 

[espensen]

No, I'm running a NON USA vac advance dist with points, connected to ported vacuum. I've tried different timing settings without any improvements of the problem.

 

[Pin_Head]

Try a larger slow jet, like a 70.

 

[espensen]

Can I drill it? I have a spare... With 0,7mm drill

 

[Pin_Head]

Drilling will work if you are careful.