Solex sidedrafts - High Idle!

[twenty6]

Hi Rodger

Have drilled out the 52.5 pilot jets to 60

They act exactly the same as the 52.5 in that the car just continues to turn over with no sign of starting. Have cleaned the plugs and checked fuel and all is ok there.

Also noticed the other set of pilot jets I have with the soldered up holes, the pilot jet size hole on the bottom seems larger than the 60 I just drilled.

This is driving me crazy!

Regards

Cam

[Steve M]

pilot jets shouldn't make a difference to whether the engine starts or not.

[twenty6]

Hmm that's interesting suppose that's good and bad news wonder what it is then..

[Rodger]

From a PM from Killa so all can relate and may relate to Twenty6's issue

im haveing some problems with my 2tg motor.

the car hasnt been idleing properly or reving properly, if you rev the motor it takes a while for rev's to drop. it coughs and farts out of the carby's or exhaust.
comppresion test was 120psi and number 2 was 100-105 (cold and semi warm)

so
i replaced
new coil with ballast,
plugs
ordered new leads
both electronic and normal 2tg dizzy doesnt make a change

have set the timing between 12-16 BTDC
fule pressure has been around 3-3.5psi

ventruies are all nice and tight.
i took the top cover of the carby's off and check that (going off your website)

the two small jets are 57.5 on all of them(pilot jet??)
the top small ones that are screwed into the big long jets are 130's(main air jet??)
once those ones are off the long ones have a 8 on them. (jet block)
i took the long jets out and they have 130 underneath of them.(main air jet)
and didnt look at the bleed pipe

the idle mixture screws dont look to well, the first carby still retains the long needle point on it, then the other 3 mixture screws dont have the needle pin on them, there missing. seem to have broken the pin point.

silly car chick thinks that the cam's arent setup correctly or timing chain issue due to lower compression.

i dont have any history about the motor, it seems to have modifyed cams in it for the way it lumps or that could be due to the fact the mixture screws on 3 of them are stuffed???

also on top of the carby number 1, it has this vacume thing which is the bracket for the choke, it doesnt seem to do anything so i just put a bung on the balance pipe.
a pipe runs off the bottom of balance pipe to a canister under neath the manifold. dunno what that is

i dont know what else i can do. but its not running well at all.

First thing to look at, are the tips of those broken idle mixture screws are still lodged into the idle hole? A torch shone down the screw hole will either revel a plugged hole or you will see down onto the throttle plate. Compare them to the one not broken.

The tips break off when the screws are seated closed too tightly, they break off very easily and as they have been tightened the tip has been jammed into the hole.

If the Idle holes are plugged, then the motor will never idle or progress from idle as those three cylinders are getting no fuel from the idle circuit. The bypass circuit and the balance tube assemblies can compensate only a little and hence the reason the motor can be started as one idle circuit is supplying all four cylinders.

It will be an absolute prick to drill out the plugged holes. I have done it and it takes a good drill press or mill to square up and align the body to drill them out. They are from memory 0.8mm holes but check the good one.

Otherwise it is another pair of bodies to transfer all the good bits into.

Regards

Rodger

[twenty6]

edit - ^ those are the mixture screws.

So I took the carbs off and looks like they are all broken, 1 carbs both holes are clear the other carb has both tips lodged in and I don't think they are coming out... Can anyone confirm these are 0.8mm holes? Angry :@

If I clear them, where can I get 4 replacement mixture screws the same type?

Nice troubleshooting.

[Steve M]

The one on the far right looks fine. The others have all been over tightened too many times, bugger!.
Different version of the carbs use different length idle mixture screws.

Does Rodger supply idle mixture screws?

[twenty6]

The replies to this thread have been great so far everyone's pretty spot on with their thoughts.

My friend has access to a few things in a big workshop so will attempt to drill the 1 carb out, can anyone please confirm they are 0.8mm?

Yeah hopefully Rodger does, I will start looking locally too.

[Steve M]

I would be careful when clearing the idle mixture hole. I think the material blocking the hole may be harder that the carbutetor body. If this is the case, you might run the risk of damaging the actual carby body in that area and then may never be able to tune the idle accurately for that port.
The blockage should be pushed out from the inside of the port. THere may be a blocked service hole on the outside of the carburetor that could be used to gain access.

Be careful when playing with carbies, it's very easy to screw them up.
My brother is using some older phh-2 carbies, which we think might be made from magnesium. They are very soft and the mounting flanges bend and warp if over tightened around soft mounts. The venturi tensioning screws strip in them very easily too. I had to Q bond a nut to one carby to be able to install the small venturi.

[twenty6]

Haha oh man.. Damn carbies.

I have taken them off so I have been clearing them from the inside out, No way would I try the other way. But yeah, going to attempt to get them drilled out once I can get the size confirmed. I guess I'll be posting back here once that's done and I find some mixture screws if I'm still having problems

Funny you should mention that, here's a pic of why I bought new carbs.

Just started to make a whistling high pitched sound on deceleration after I painted my car and put the motor back in, after a while I decided to put my hand under the carbs and felt fuel on my hands.. bit of pressure applied with my finger and the grub screw with accompanying metal was sitting in my hand.. :\ lucky I wasn't driving, my extractor is right under it.

I put it down to having no heat wrap/shield after the rebuild as it got removed by someone, although I'm not sure? I have since re-wrapped since buying the new set of carbs.

[Rodger]

twenty6.

I have yet to confirm the hole size but a couple of tips that will help drill out any plugged ones. If you have access to a good range of small drill bits in 0.1 steps then try them in one of the clear holes to determine the hole size for your carbs.

I have drill sets in 0.05mm steps from 0.2-2.00mm, hard to come by but available.

Set the carb square on the table.

Use a 4.5mm drill bit, the prefered tap-drill size of the 5 x 0.5mm threaded hole (or one that fits in well enough), turned upside down to align/centre the body with the drill chuck.

No use a smaller bit to the one that matched the hole size to start with.

Lower the drill onto the plugged bit of brass and turn by hand. You may find that you can remove the plug as the drill bit bites into it. Otherwise continue by hand to drill through.
Then check how centred it was and use the prefered size to grab the plug as it now could come free.

If it goes well the hole need not be touched or drilled completely. If goes badly all four holes can be drilled to the next size. It means the idle mixtures become a tiny bit more sensitive to change when tuning but will still work.

Regards

Rodger

[petergoudie]

Before you go drilling anything check the holes are just not blocked with dirt or aluminium diecast corosion. I would think it very hard to break a tip off and leave it in there. The brass should be harder than the diecast.

[Rodger]

Unfortunately very very easy to do.

Both Killa and Twenty6 have threads running with the same problem.

I have at least four Solex bodies here in my vast collection with plugged idle mixture holes. It is one common reason to sell used Solexes as they have been found frustratingly difficult to tune so become junk, in the eyes of the owner.

Regards

Rodger

[Killa_Ta22]

Yeah i should have looked at the mixture screws first up lol, Mine are definatly lodged and broken off in the hole!!

but i dont have enough experience, so i'm getting Rodger to set the mixture screws up for me and may need to tinker with them a smidge..

I very thankful for Rodgers help!

Cheers, Dan

[twenty6]

twenty6.

I have yet to confirm the hole size but a couple of tips that will help drill out any plugged ones. If you have access to a good range of small drill bits in 0.1 steps then try them in one of the clear holes to determine the hole size for your carbs.

I have drill sets in 0.05mm steps from 0.2-2.00mm, hard to come by but available.

Set the carb square on the table.

Use a 4.5mm drill bit, the prefered tap-drill size of the 5 x 0.5mm threaded hole (or one that fits in well enough), turned upside down to align/centre the body with the drill chuck.

No use a smaller bit to the one that matched the hole size to start with.

Lower the drill onto the plugged bit of brass and turn by hand. You may find that you can remove the plug as the drill bit bites into it. Otherwise continue by hand to drill through.
Then check how centred it was and use the prefered size to grab the plug as it now could come free.

If it goes well the hole need not be touched or drilled completely. If goes badly all four holes can be drilled to the next size. It means the idle mixtures become a tiny bit more sensitive to change when tuning but will still work.

Regards

Rodger

Thanks for the help,

Do you have any mixture screws available or know any sources to get them?

[twenty6]

Found at wolf creek racing, 4 x idle mixture screws for $41USD shipped to me so thinking that's my best option. Guess I will post back here once I receive them and have the bodies sorted Thanks for everyones help.

Oh, and because I don't want to go through this again and it sounds like a common thing to happen, how do you prevent over tightening? Where's the point that they shouldn't be tightened over? Thanks