[alchemysa]

This is the carby on the 83/84 Sj40T I'm fixing up for my daughters little farm. The car runs 'fair' but idles rough and briefly dies if you accelerate too fast. So I've completely stripped and cleaned the carby. It was very dirty inside but otherwise looked basically OK.

The only thing I haven't touched is the bit circled in the pic. I'm assuming its the idle mixture screw but its under a plastic disc. How do you get the disc off? Just lever it out? And does it serve any purpose other than making the screw hard to get at?

My other query concerns the looped rubber tube I've arrowed. This doesn't look 'factory spec' to me. Can anyone tell me where these tubes are supposed to go and will the car generally be OK if they stay like this? (All the anti pollution gear has been removed or disconnected).

Thanks for any help.

[sideways]

I'm guessing they're ported vacuum lines for the vacuum advance(dunno why they'd have 2 though...). It doesn't matter if they're hooked up like that or just blocked off. They serve no function.

Smash through the anti tamper disc. It's there to stop you fiddling with the idle mixture as they're set to pass emissions.

[christover1]

Fuel pump could be too old, bits come off and block the idle jet.
Extra filter before carb, after pump is wise.
Fuel tank may have a drain plug, could easily be a layer of water/mud in bottom of tank.
Fit an inline efi filter instead of factory, cheap insurance for clean fuel.
Metho in the tank once a month can help.

[alchemysa]

sideways wrote:

I'm guessing they're ported vacuum lines for the vacuum advance(dunno why they'd have 2 though...). It doesn't matter if they're hooked up like that or just blocked off. They serve no function.

Smash through the anti tamper disc. It's there to stop you fiddling with the idle mixture as they're set to pass emissions.

Thanks Sideways. Thats what I hoped.

[2stroker]

They have a small mesh screen filter that gets clogged up and causes fuel problems, i will have to go pull one apart in the morning so I can remember exactly where that little screen filter is, I think it is just before the needle and seat.

[alchemysa]

christover1 wrote:

Fuel pump could be too old, bits come off and block the idle jet.
Extra filter before carb, after pump is wise.
Fuel tank may have a drain plug, could easily be a layer of water/mud in bottom of tank.
Fit an inline efi filter instead of factory, cheap insurance for clean fuel.
Metho in the tank once a month can help.

All good thoughts Christover. Fuel tank is not original. Its off something unknown. Theres probably a cocktail in there. Fuel cap doesn't fit properly so probably lots of dirt. The tank looks like it has a plug so I guess I should try and flush it out. Inline filter has been added but another one after the pump is on the cards. There was a lot of crap in the little mesh filter below the carby banjo fitting.

[alchemysa]

2stroker wrote:

They have a small mesh screen filter that gets clogged up and causes fuel problems, i will have to go pull one apart in the morning so I can remember exactly where that little screen filter is, I think it is just before the needle and seat.

Yes, I almost missed it. Its just below the banjo fitting. It was pretty dirty.

[alchemysa]

I cleaned the idle mixture screw. What a difference. The engine is purring. The only trouble now is its dieseling for a few seconds when its hot. (Was doing it before the cleanup too). Theres no solenoid on this. Any suggestions on the cause of this? I searched a bit. Float level was suggested but I'm a bit dubious about that.

[christover1]

After running bad for a bit, engine could be carboned up, it could come good after running right for a while.

[alchemysa]

christover1 wrote:

After running bad for a bit, engine could be carboned up, it could come good after running right for a while.

Yeah, plugs were pretty black. Other googled reasons are 'timing' and 'mixture too rich'. Thats possible.