73 Solex & EGR

Opelmel · 09-30-2008

I'm the new owner of a 73 GT. Fun car, but starts & idles rough. In pulling the carb today I discovered that the fast idle doesn't seem to work, and there are 3 holes in the base of the carb on the valve cover side. There's a vacuum leak through one of the holes, which has been temporarily plugged with duct tape. I know that there used to be an EGR system on the car, but it's off now. Are those holes from that? What other holes should I be looking for from that system?

As for the fast idle, I pulled the electric choke cover off and straightened out a piece that was slightly bent, but it still doesn't seem to hold a fast idle. Anybody have any pics/diagrams of how the insides of that choke should look? I'd like to know that I can get that part set up properly before I spend the money on a rebuild kit for the rest of the gaskets and such. I know, get a Weber! But this thing is getting 30 mpg as-is, and I've heard that the Weber isn't as efficient, so I'd like to keep it stock. No, I'm not cheap - just frugal!

rme · 10-01-2008

Here's a couple of prior posts that might help:

http://www.opelgt.com/forums/group-6...nnections.html

http://www.opelgt.com/forums/6e-tune...ver-hoses.html

I didn't find it quickly, but someone has previously posted a picture of the hoses with call-outs showing exactly where they go.

Opelmel · 10-01-2008

I've got the usual hoses squared away (I think), but I'm still trying to figure out what the holes are for on the inboard (valve cover) side. And fast idle is still not cooperating. Anyone with ideas/suggestions?

BQS4 · 10-01-2008

Originally Posted by Opelmel

I've got the usual hoses squared away (I think), but I'm still trying to figure out what the holes are for on the inboard (valve cover) side. And fast idle is still not cooperating. Anyone with ideas/suggestions?

On the valve cover, the large hole is to go to your air cleaner assembly, be it stock or aftermarket. the smaller hole is to go to the intake on the motor side, down below the carb. Some intakes have this, some don't. Also keep in mind, intakes could have been swapped out.

Opelmel · 10-01-2008

I'm pretty sure I've got the holes on the valve cover squared away. It's the holes on the base of the carb itself, on the valve cover side, that have me puzzled.

timemachine · 10-02-2008

You are talking about what looks like a missing diaphragm mount, right? I asked myself the same question in 1974. Disregard the unused holes. They are for a different application of this carburetor.

Jim

tomking · 10-02-2008

Well there are two connections on the engine side of some Solex carbs. One is simply the vent for the bowl area and is on the top of the carb towards the front. The other is on the firewall side of the carb and difficult to get to; it faces the engine though. I think, may be wrong, it is the port to which the vacuum cannister attaches.
Not all carbs have a large port to vent the bowl, nor do all carbs have a port to attach a vacuum cannister.
Do a search for vacuum connections posted by Otto, Tekenaar as I think he posted some good pictures of the connections recently.

tekenaar · 10-02-2008

Originally Posted by tomking

Well there are two connections on the engine side of some Solex carbs. One is simply the vent for the bowl area and is on the top of the carb towards the front. The other is on the firewall side of the carb and difficult to get to; it faces the engine though. I think, may be wrong, it is the port to which the vacuum cannister attaches.
Not all carbs have a large port to vent the bowl, nor do all carbs have a port to attach a vacuum cannister.
Do a search for vacuum connections posted by Otto, Tekenaar as I think he posted some good pictures of the connections recently.

. . . as Tom said . . .

. . . and . . .

Opelmel · 10-02-2008

The ones that I'm talking about are in the base plate, the same plate that the throttle linkage is connected to. One is definitely some sort of vacuum port, since I can stick a finger on it and feel the vacuum. I'm guessing that it had something to do with the EGR system. I guess I'll just plug them and hope for the best.

Any ideas on how to set the high idle?

Crazy Harry · 10-02-2008

The drawing is from a rebuild kit for the carb on my '71 GT. Do you mean the holes for items 47, 48 & 49. I'm assuming these are missing from your carb and that's why you found the holes.

This is the Hot Idle compensation: "The normal idle system provides a fuel mixture which is too rich when the engine is unusually hot. To compensate for this, the bi-metal spring of the hot idle compensator valve (48) located on the secondary barrel of the throttle body (50) is lifted to open a passage (the hole you're asking about) through which additional air is drawn in. This additional air leans the idle mixture to prevent a hot engine from stalling." Stolen from an Opel Carburetion Training Manual, I've added the numbers to correspond with the figure and the comments in brackets.

If your engine doesn't get too hot (which I doubt) then plugging shouldn't be a problem.

Hope this helps,

Harold.

Opelmel · 10-02-2008

Those are the holes that I was referring to. Thank you for the details. You're right - extreme heat generally isn't a problem here. Now I just need to plug them off, and get the fast idle working.

tekenaar · 10-03-2008

Originally Posted by Opelmel

Those are the holes that I was referring to. Thank you for the details. You're right - extreme heat generally isn't a problem here. Now I just need to plug them off, and get the fast idle working.

BEFORE you remove anything, check this first and save yourself some time!! . . . does your Solex have those two vent pipes shown in my pics?

If so, that's not your idle problem! Your carb would be a late, "emissions" carb which does NOT use a hot idle compensator and the unthreaded hole in the base of the carb is NOT drilled all the way through into the secondary throttle bore, i.e. no vacuum leak there!!! Only the '68 to early '70 Solexes used that device and actually have that hole drilled all the way through!

Opelmel · 10-03-2008

It's getting very strange! My carb has 2 hoses coming from those spots and going to the charcoal canister. But there's no question that there's a vacuum situation with the hole in the base plate. I put my finger there with the engine running and I can feel the suction, and the engine runs noticeably better when I block that hole off.

If that wasn't a connection for the EGR system, could it be that a PO put in a Solex from a different year when the EGR system was yanked?

Crazy Harry · 10-05-2008

Check if the carb still has the aluminum tag with a number on it. For example: A '71 GT with a standard transmission had a Solex with tag #3441549. With this # you can determine what model year it is. I have a partial list somewhere, post the number if you can find it and someone should be able to help identify the carb.

Harold.

Opelmel · 10-07-2008

The tag number on my carb is 3441 826A. Thanks for checking it for me.

Crazy Harry · 10-07-2008

Opelmel: My list goes up to MY 1972 and the highest number is 3441595 on a 1972 1900 Manual (Calif.). Maybe it is a '73 carb. Sorry, does anyone else have any "newer" information????

Harold.

Crazy Harry · 10-08-2008

Check section 6E of the Factory Service Manual on this site, the carb for a '73 GT with a manual trans has tag number 3441826 (table on the last page of that section). So you definitely have a 1973 carb. Link:

http://www.opelgt.com/forums/local_l...&catid=4&id=43

I don't know if the "A" at the end of your tag number has any significance.

Harold.

Opelmel · 10-09-2008

Thanks, Harold, for the info.
I think the "A" on the tag stands for "A"in't ever gonna work right!
Mel

BQS4 · 10-09-2008

Just taking a "shot in the dark" here, if you're talking about original solex carbs, the "A" could stand for "aqua", or water, meaning it has a water operated choke, which the earlier solex did. But, this is just a guess....

Opelmel · 10-09-2008

At least I don't think it is, since the choke is electric (and not all that good, I might add).

09-30-2008	#1 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	Unanswered: 73 Solex & EGR I'm the new owner of a 73 GT. Fun car, but starts & idles rough. In pulling the carb today I discovered that the fast idle doesn't seem to work, and there are 3 holes in the base of the carb on the valve cover side. There's a vacuum leak through one of the holes, which has been temporarily plugged with duct tape. I know that there used to be an EGR system on the car, but it's off now. Are those holes from that? What other holes should I be looking for from that system? As for the fast idle, I pulled the electric choke cover off and straightened out a piece that was slightly bent, but it still doesn't seem to hold a fast idle. Anybody have any pics/diagrams of how the insides of that choke should look? I'd like to know that I can get that part set up properly before I spend the money on a rebuild kit for the rest of the gaskets and such. I know, get a Weber! But this thing is getting 30 mpg as-is, and I've heard that the Weber isn't as efficient, so I'd like to keep it stock. No, I'm not cheap - just frugal!

10-01-2008	#3 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	Thanks I've got the usual hoses squared away (I think), but I'm still trying to figure out what the holes are for on the inboard (valve cover) side. And fast idle is still not cooperating. Anyone with ideas/suggestions?

10-01-2008	#5 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	Holes I'm pretty sure I've got the holes on the valve cover squared away. It's the holes on the base of the carb itself, on the valve cover side, that have me puzzled.

10-02-2008	#6 (permalink)
timemachine Member Join Date: Jan 2006 Location: Swarthmore, PA Posts: 871 Real Name: Jim Provided Answers: 7	You are talking about what looks like a missing diaphragm mount, right? I asked myself the same question in 1974. Disregard the unused holes. They are for a different application of this carburetor. Jim __________________ '74 Manta ("Sig") '75 Sportwagon (project) '72 GT (whenever I get to it) Sold or wrecked: '72 Manta Rallye '73 Manta '74 Luxus

10-02-2008	#7 (permalink)
tomking tomking Join Date: Aug 2002 Location: SW Missouri Posts: 1,287	Well there are two connections on the engine side of some Solex carbs. One is simply the vent for the bowl area and is on the top of the carb towards the front. The other is on the firewall side of the carb and difficult to get to; it faces the engine though. I think, may be wrong, it is the port to which the vacuum cannister attaches. Not all carbs have a large port to vent the bowl, nor do all carbs have a port to attach a vacuum cannister. Do a search for vacuum connections posted by Otto, Tekenaar as I think he posted some good pictures of the connections recently. __________________ TMK

10-01-2008	#2 (permalink)
rme Opeler Join Date: May 2006 Location: Eastland, Texas Posts: 39	Here's a couple of prior posts that might help: http://www.opelgt.com/forums/group-6...nnections.html http://www.opelgt.com/forums/6e-tune...ver-hoses.html I didn't find it quickly, but someone has previously posted a picture of the hoses with call-outs showing exactly where they go.

10-02-2008	#9 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	Different holes! The ones that I'm talking about are in the base plate, the same plate that the throttle linkage is connected to. One is definitely some sort of vacuum port, since I can stick a finger on it and feel the vacuum. I'm guessing that it had something to do with the EGR system. I guess I'll just plug them and hope for the best. Any ideas on how to set the high idle?

10-02-2008	#11 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	Those are the ones! Those are the holes that I was referring to. Thank you for the details. You're right - extreme heat generally isn't a problem here. Now I just need to plug them off, and get the fast idle working.

10-03-2008	#13 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	Solex got me confused! It's getting very strange! My carb has 2 hoses coming from those spots and going to the charcoal canister. But there's no question that there's a vacuum situation with the hole in the base plate. I put my finger there with the engine running and I can feel the suction, and the engine runs noticeably better when I block that hole off. If that wasn't a connection for the EGR system, could it be that a PO put in a Solex from a different year when the EGR system was yanked?

10-05-2008	#14 (permalink)
Crazy Harry Opeler Join Date: Jan 2007 Location: Oakville, Ontario, Canada Posts: 94 Real Name: Harold Provided Answers: 1	Solex Model Year Check if the carb still has the aluminum tag with a number on it. For example: A '71 GT with a standard transmission had a Solex with tag #3441549. With this # you can determine what model year it is. I have a partial list somewhere, post the number if you can find it and someone should be able to help identify the carb. Harold.

10-07-2008	#15 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	Tag Number The tag number on my carb is 3441 826A. Thanks for checking it for me.

10-07-2008	#16 (permalink)
Crazy Harry Opeler Join Date: Jan 2007 Location: Oakville, Ontario, Canada Posts: 94 Real Name: Harold Provided Answers: 1	Need Newer Tag Number Cross Reference Opelmel: My list goes up to MY 1972 and the highest number is 3441595 on a 1972 1900 Manual (Calif.). Maybe it is a '73 carb. Sorry, does anyone else have any "newer" information???? Harold. Last edited by Crazy Harry; 10-07-2008 at 11:53 PM.

10-08-2008	#17 (permalink)
Crazy Harry Opeler Join Date: Jan 2007 Location: Oakville, Ontario, Canada Posts: 94 Real Name: Harold Provided Answers: 1	Check 1973 FSM Check section 6E of the Factory Service Manual on this site, the carb for a '73 GT with a manual trans has tag number 3441826 (table on the last page of that section). So you definitely have a 1973 carb. Link: http://www.opelgt.com/forums/local_l...&catid=4&id=43 I don't know if the "A" at the end of your tag number has any significance. Harold. Last edited by Crazy Harry; 10-08-2008 at 12:38 AM.

10-09-2008	#18 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	A on the tag Thanks, Harold, for the info. I think the "A" on the tag stands for "A"in't ever gonna work right! Mel

10-09-2008	#19 (permalink)
BQS4 Southern Red Neck Join Date: Mar 2002 Location: Snellville, GA Posts: 6,028 Real Name: Gene Provided Answers: 12	Just taking a "shot in the dark" here, if you're talking about original solex carbs, the "A" could stand for "aqua", or water, meaning it has a water operated choke, which the earlier solex did. But, this is just a guess.... __________________ "Yes, I do have a rifle rack in my Sportwagon"

10-09-2008	#20 (permalink)
Opelmel Lurker Join Date: Jul 2005 Location: Omro, WI Posts: 73	A isn't for Aqua At least I don't think it is, since the choke is electric (and not all that good, I might add).

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