33 Webers

[Joey]

Hey guys, have one cylinder not running/misfiring at idle. I know what cylinder it is and I am sure it is not getting fuel. (it runs when a fuel soaked rag is put in front of the inlet. What would you guys suggest needs cleaning out?

[colcol]

Hello Joey, take the inlet off the top of the carby, 2 nuts and 1 long bolt, then undo the 4 cheese head screws on the carby cover and carefully lift it away, but be very carefull as it has the needle and seat assembly and and easily torn gasket, you will now see 6 jets, 4 small ones and 2 big ones, undo these and take them out and pull them apart, they are a push fit together, using compressed air blow out the jets util you can see through the orifice's by holding them up to a light, i don't know which jets do what, but you have all 6 out, give them all a clean, assemble them back in and put the cover back on and start the car and see how you go, keep us informed, Colin.

[philpot]

Hi Joey

Maybe as a step prior to the above, perhaps after taking off the carbyinlet/aircleaner assembly. You can try this: remove the small brass idle jet screw (there is one per cylinder) on the offending cylinder, which sits flush to the top of the carby, just beside the barrel (and between the two)  on the edge of the gasket. Remove the idle jet and have a look at the tiny hole (0.47mm as std) to see if you can see through the end. The two halves separate so you can blow it through with your mouth if a compressor and air hose aren't handy...like at the side of the road for instance!

Before replacing now cleared idle jet, find a biro and remove the innards, so that your left with a tube. Place biro gently into idle jet hole and GENTLY blow air though, you'll see a little squirt of fuel onto the throttle butterfly if all is clear. Dont do with too much gusto as fuel can blow back up into your face through the two big main jets , which are the big sticking up brass tubes/screws with the air/emulsion hole down the middle; one for each cylinder, again.

If ever a multi carb boxer starts to not idle properly or run rough on light/cruise throttle, this is the first thing you try. With such a small jet, and being one per cylinder, they have a big effect if one blocks up!

[Joey]

5min and its running beautifully now!
Thanks very much guys.

[colcol]

But before you remove the idle mixture screw screw it in all the way home, counting the number of turns clockwise until it bottoms, then once you blow out the blocked mixture screw you can put it back to its original place without having to tune the engine, a quick way to find the offending cylinder not running is to have engine stopped, remove spark plug insulation on spark plug end, start engine and use big insulated screwdriver AND insulated gloves and go round engine and short out each spark plug, a good cylinder will stumble and slow down when shorted out, the non working cylinder will not stumble as it is not working any way, or you can remove the 4 spark plugs after idling and the one that is a different colour to the other 3 is the one thats getting no juice, Colin.

[Joey]

But before you remove the idle mixture screw screw it in all the way home, counting the number of turns clockwise until it bottoms, then once you blow out the blocked mixture screw you can put it back to its original place without having to tune the engine, a quick way to find the offending cylinder not running is to have engine stopped, remove spark plug insulation on spark plug end, start engine and use big insulated screwdriver AND insulated gloves and go round engine and short out each spark plug, a good cylinder will stumble and slow down when shorted out, the non working cylinder will not stumble as it is not working any way, or you can remove the 4 spark plugs after idling and the one that is a different colour to the other 3 is the one thats getting no juice, Colin.

I just cleaned out the jets, didn't touch the idle mixture screw, or am I confused?
next question, I fired it up with the cover off the air box, wow what a noise! The intake noise is epic. Are there many air intake options, mainly just to safely get a bit more of that beautiful intake noise!

[colcol]

Hi Joey, i usually just clean out the jets at the top of the carby when i have a miss in the engine, but sometimes the mixture screws need a cleanout as well, there are 2 of them on the side of the carby, and they screw in and out to adjust the idle mixture, if the car is running well, then leave them alone, they are the second item i clean up when chasing down the miss in the engine, Colin.

[philpot]

Hi Joey, good to hear your prob was fixed. I always find its best to start with the simplest solution first to see if that works, then take it from there. Re the sound, yes the boxers sound bloody brilliant with the aircleaner assembly off !

A simple solution to get more air in/sound out is to remove thermo air valve diverter assembly below the LHS bottom of the air cleaner box and go out and buy some flexy plastic piping (that has wire spiral re-enforcing) to place into the inlet. Yes, its a square hole, but the flexy hose deforms to slot in. Slot intake end of pipe into ring bracket to hold near upper LHS side of radiator. If ur car has A/C, take the tube over the compressor.

If you're really keen, you can add another intake entry into the air cleaner on the RHS at the front, by drilling a hole and fabricating a peice of aluminium tube of smaller dia. than the pipe, riveting/silicon the bracket on, then running another flexi air pipe over the rad fan assembly to the Upper RHS of the radiator. You'll need to get another bracket to take the end of the pipe...

These mods not only let more air into the airbox, but even out the flow of air as well, having inlets on each side.  AND...they sound really good and pretty much look O/E...

Cheers, Phil.

[Joey]

Hi Joey, good to hear your prob was fixed. I always find its best to start with the simplest solution first to see if that works, then take it from there. Re the sound, yes the boxers sound bloody brilliant with the aircleaner assembly off !

A simple solution to get more air in/sound out is to remove thermo air valve diverter assembly below the LHS bottom of the air cleaner box and go out and buy some flexy plastic piping (that has wire spiral re-enforcing) to place into the inlet. Yes, its a square hole, but the flexy hose deforms to slot in. Slot intake end of pipe into ring bracket to hold near upper LHS side of radiator. If ur car has A/C, take the tube over the compressor.

If you're really keen, you can add another intake entry into the air cleaner on the RHS at the front, by drilling a hole and fabricating a peice of aluminium tube of smaller dia. than the pipe, riveting/silicon the bracket on, then running another flexi air pipe over the rad fan assembly to the Upper RHS of the radiator. You'll need to get another bracket to take the end of the pipe...

These mods not only let more air into the airbox, but even out the flow of air as well, having inlets on each side.  AND...they sound really good and pretty muck look O/E...

Cheers, Phil.

Sounds like a great mod, what are you meaning by flexi hose? Having the engine sucking cold air in sounds like a great idea. If I can work out where to get this hose from I would love to do this mod tomorrow morning! My other idea was to fit one of the K&N sets http://www.knfilters.com/air_intake/alfa_romeo_33.aspx

[colcol]

You can buy the flexiable black plastic spiral hose at industrial supply places, i got mine from Thomas-Warburton, but most places have it, the only problem is find a place where you can buy a minimum amount, as you don't want a whole roll!, it is best to have 2 inlets in your air cleaner as it is more balanced and if you have only 1, then only 1 side of the air cleaner gets dirty, to pick up cold air i removed the 2 horns and relocated them under the car at the front, and where the horns used to be be, thats where i picked up the cold air for the hoses, for mounting them i put a hole in a hose clamp and fastened it to the mount where the horns were, and tightened the hose clamp around the hose inlet, and this seems to work ok, Colin.

[philpot]

Hi Joey, depending on which state or capitol you're in, google industrial hoses/fittings and industrial hose pipe manufacturers/retailers. In Melbourne, Purple Pig (yes...) inBayswater is happy to sell by the metre or whatever length you need. It comes in various dia. i used 60mm internal diameter on my twin set up.
Yes, seen the K&N chromey dual IDF set up, there's a similiar thing on ebay if you search 'alfa 33'. Never seen or heard in action, but to my way of thinking they'd be sucking in very hot air above the engine, especially in traffic/at idle, unless being fed by pipes directing air at them. For that reason haven't gone the pod route with my 16V, as the std air box pics up air from down near the RHS Rad cutout already. Have put a K&N panel filter in tho...
Oh, as a way of evening air filter wear on the std setup, you can just rotate element every 5000 or so...
Let us know what you get up to !
Cheers, Phil