Hi Al,

Thanks for the explanations. Regarding the carb; flooding/float level and it's condition is there a writeup or manual that shows how to do these tasks? (I'm completely a novice regarding carbs..and other things )

Also, I noticed there are 2 springs (rather than 1) on the accelerator cable-to-carb mechanism? Could this be somehow creating an issue? I don't know why there are 2 springs...

turbo500 said:

Hi Al,

Thanks for the explanations. Regarding the carb; flooding/float level and it's condition is there a writeup or manual that shows how to do these tasks? (I'm completely a novice regarding carbs..and other things )

Also, I noticed there are 2 springs (rather than 1) on the accelerator cable-to-carb mechanism? Could this be somehow creating an issue? I don't know why there are 2 springs...

Click to expand...

Most people follow the manual when checking/resetting the float level. Without pictures or diagrams, it might only confuse you trying to explain it in words. I don't have a manual but hopefully another member might put up some pics and talk you through it. I'd first check the other items mentioned though, before going near the float valve.

Afaik there should only be 1 spring on the cable to carb mechanism. Is there a bellcrank and link rod between the cable and the carb? Can you post a pic of these 2 springs?

Sorry I can't be of more help,

Al.

Youve been very helpful, I appreciate it!

I think I have the workshop manual for the Weber 26 so it's just a matter of getting to it...

Here's the dual spring accelerator! (don't know why the picture is upside down)

That's a homemade setup on the spring isn't it? I wonder if the single one wasn't strong enough to get the pedal to reset (possibly a tight/rusty cable in the sheath?) and so they just whacked another spring on to get it up.
The joys of taking over someone else's project!

There is a writeup somewhere on this forum that talks about hiw to setup and adjust a 26 and 28 imb carb.

BambinoClassic said:

That's a homemade setup on the spring isn't it? I wonder if the single one wasn't strong enough to get the pedal to reset (possibly a tight/rusty cable in the sheath?) and so they just whacked another spring on to get it up.
The joys of taking over someone else's project!

Click to expand...

No clue, will have to experiment and see if that's the case. I plan on cleaning the pedals so will see if there's something there that's obstructing pedal/cable travel.

Luxe said:

There is a writeup somewhere on this forum that talks about hiw to setup and adjust a 26 and 28 imb carb.

Click to expand...

I think this might be it? A great read and well put together that I bookmarked to read for when I'm up for the challenge.

Ok so today I turned the 500 on, and noticed that something was strange.

The only thing I did engine related was the following:
-Installed rubber piping between engine and heater tube
-Removed fuel line from gas tank to temporarily remove gas tank

I turned the car on and noticed it would die unless I kept the choke lever open. So I warmed up the engine and turned it off. Then screwed in the air screw fully, then unscrewed it 1.5/2 turns. Started it again and fiddled with the accelerator screw.

I got it to run normal, but it would 'cough' every so often, also from time to time it would speed up and slow down. Then I tried replicating accelerating and coming to a stop. In the second video you can see how it dies when the revs drop simulating coming to a stop on the road.

Also, I noticed that there was a lot of bubbles coming from the fuel pump into the fuel filter (I'm pretty sure this wasn't the case beforehand). So could this be because I let air into the fuel line when I removed the gas tank? How do I resolve this?

So now the issue is it seems to be running rough for no apparent reason other than what I wrote above.

Can anyone tell what the issue could be from the videos?





Also wanted to add, unrelated, but is it normal for air to be coming out of this area (the seam marked with the zig-zag)

Did you remove the whole fuel sender from the tank, or just unplug the fuel hose from the sender on the top?
I'm wondering if there's an air leak somewhere and periodically air is getting into the line and bubbling through
Or

Do you have to prime these units when you remove the tank? Ie. bleed them of any air before reconnecting at the fuel pump end?

Some air trapped in the fuel filter is normal, but your fuel pump shouldn't be pumping air. If it is you've got a loose connection or leak somewhere. You could try removing the fuel pipe from the fuel filter and check whether you've got good fuel delivery into a bottle or jar when the starters operated. Get someone to help because you don't want fuel anywhere near the electrics. I doubt that it's fuel pump problem as your engine operates well at fast idle and high revs. It might be an optical illusion, but the top cover of your fuel filter looks distorted and might be faulty.

I think you'll find that if your ignition system is in good order, a dirty carburettor is to blame. The idle jet is very small and a grain of rust or dirt is enough to block it. I was surprised at the amount of rust coloured silt in my float chamber. I bought an aerosol can of carburettor cleaner, the type with an extension tube, and thoroughly cleaned the carburettor and jets. It's a quick easy job, but it's probably best to have a gasket set handy.

Regarding the air leaks around the cooling cowel. You'll need to replace the split rubber. Sparkplug covers, but this won't be the cause of your misfire.

BambinoClassic said:

Did you remove the whole fuel sender from the tank, or just unplug the fuel hose from the sender on the top?
I'm wondering if there's an air leak somewhere and periodically air is getting into the line and bubbling through
Or

Do you have to prime these units when you remove the tank? Ie. bleed them of any air before reconnecting at the fuel pump end?

Click to expand...

I only removed the fuel hose.
As for the bleed, I've been researching but haven't found anything that mentions the need for it.

However, could the increase in rpms that occur on its own, be this extra air getting into the carb?

Hobo1960 said:

Some air trapped in the fuel filter is normal, but your fuel pump shouldn't be pumping air. If it is you've got a loose connection or leak somewhere. You could try removing the fuel pipe from the fuel filter and check whether you've got good fuel delivery into a bottle or jar when the starters operated. Get someone to help because you don't want fuel anywhere near the electrics. I doubt that it's fuel pump problem as your engine operates well at fast idle and high revs. It might be an optical illusion, but the top cover of your fuel filter looks distorted and might be faulty.

I think you'll find that if your ignition system is in good order, a dirty carburettor is to blame. The idle jet is very small and a grain of rust or dirt is enough to block it. I was surprised at the amount of rust coloured silt in my float chamber. I bought an aerosol can of carburettor cleaner, the type with an extension tube, and thoroughly cleaned the carburettor and jets. It's a quick easy job, but it's probably best to have a gasket set handy.

Regarding the air leaks around the cooling cowel. You'll need to replace the split rubber. Sparkplug covers, but this won't be the cause of your misfire.

Click to expand...

I haven't touched the fuel pump so I'd like to think it's not at fault

I'm pretty sure I tightened the fuel hose properly so that there is no air getting in, I will check again today.



As for the second video, is there anything you guys can think of that could be causing it to stall as I release the accelerator? :bang:

Also this morning I noticed the fuel filter is bone dry....

The only time this has happened was when I ran out of fuel once. I checked and have at least an inch of fuel in the tank.


EDIT: So I turned the car on and it ran ok, still having issues idling properly and fuel filter has no bubbles. It still turns off when I rev it up and let go of the accelerator. When turned off the fuel filter is nice and full.

Will probably have a go at cleaning the idle jet.

I wouldn't worry about the fuel filter. It will drain back to the fuel pump and tank through gravity over night. My 500 is exactly the same sometimes it will be full, empty or it bubbles away like crazy. I think you will find once you are actually driving is the only time it will continue to be full up all the time. The only thing I would say, that has already been pointed out, is it does look a little bent on the tube at the bottom of it. I would look to change it just in case it does decide to crack.

If you only have an inch of petrol in the bottom of the tank I would fill it up a bit more, as the 500 tank is notorious for rusting internally and collecting sediment in the bottom of it, if you have had the tank out then it's likely you have stirred it all up, so as you say check out the jets on the carb. It might be a good idea just to whip the carb off and give it a good clean up and maybe get a repair kit and give it a good service.
Tony

Thanks Tony, I will try to put a little more fuel now that the brakes are installed and I can get it on the road.

So I cleaned up the idle jet, there was definitely some obstruction. Seems to be running more steady now. However there are still some signs of it stalling when revving it up and releasing the accelerator.

I will take it for a spin tomorrow and see.


On a side note......I noticed there are some drops falling on the ground that are coming from the rear of the oil pan gasket when I do some high revving. Oil level is 1/3. Not too worried right now and I have a brand new cork gasket in case it gets worse...I would like to ideally get a new pan, because the current stock one is a bit battered and bruised, any benefit of getting a larger aluminum one like this 3.5l one:


Considering it's over 25°c most of the year where I'm at and the engine is a stock 499cc. I know there are some even larger pans like 4/4.5/5L....

Ciao

Ok, so I took the 500 out for a 15 minute drive. It never stalled!..well only towards the end of the 15 minutes, I think it might have to do with the extremely low fuel level. Is the gen light supposed to be on when it's idling or should it be dim/off? Because the light started to turn on when it was sputtering.

I tried doing a few 40km/h stops and also reversing and braking but the brake pedal is still a bit numb, and only starts working towards the end of the travel. The handbrake engages well around 3-4 clicks so I think that's good.
I think there is something with the rear brakes, because I had a hard time putting the new drums over the new pads/spring/handbrake hardware. Both rears are difficult to turn by hand. In fact, when I stopped driving, I went to touch the rear rims, and they were hot, so there is definite rubbing between drums and pads, what do you guys recommend?

Something else I noticed is this noise, that seems to appear around 40km/h and up. I think it's coming from the gearbox/axles/hubs? Seems more like a low end noise then a top of engine noise. The video was recorded with the phone on the rear seat bottom, then I moved it up to the rear parcel shelf.



Last but not least, I noticed that the pulley belt is trowing some oil onto the engine compartment and especially visible on the rear hood (on the heat shield).
I felt around and there doesn't seem to be any wet spots, just the belt has some oil on the inside part. I'm thinking of just changing the belt (visible damage as well on it).

Bubbles in the fuel line are normal so don't worry about it. Regarding the oil pan I have put it in my car and I can tell you that it is very effective. I live in Greece with temp more than 30-35 degrees I highly recommend it. I will also suggest you to buy new ignition leads and spark plugs as well as an electronic ignition module like powerspark, it cost around 50$. You will have a much smoother engine operation.
Thomas

3-4 clicks on the handbrake sounds a bit tight to me. Iirc Fiat recommended something like 5-7 clicks to fully applied.

Maybe try backing off the adjustment a little.
The brake drums should turn without binding.
Re-adjusting the handbrake might help with this.

Al.

The workshop manual says to jack up the rear, and pull the handbrake 2 clicks, then do some adjusting with the nuts on the handbrake cables until wheels move with some resistance, then release parking brake and wheels should turn freely.

Is that right?
Also, could it be the brake pedal pushrod is worn out and hence works only towards the end of the pedal travel?

This is a possibilty. Although they sell a sibgle master cylinder for 500 and 126 the cats themselves have different length pedal box pins. If you end up with the wrong pedal pin / master cylinder mix - you will not push the master cylinder piston far enough.
I had to make an adjustable pedal box pin to get correct bite point on pedal travel.