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Discussion Starter · #1 ·
Hello all,..Question (s) .....i have a 74 Manta 1.9L (stock) with electronic p/u in dizzy...
I had a Weber 32/36 on it last yr, but it was getting like 10 mpg, (no kiddin!) even trying to lean it
out was a lesson in futility.

I put the world renowned, and beloved :lmao: Solex back on it to get some semblance of economy/mileage etc back.
I live in Denver Co and want to find a brick & mortar store (not Internet order if poss)
that i can walk into and buy a high altitude kit for it. if i have to order online, i will, but would like to get
it sooner if poss.

I dont know whats in the Weber now, i will be taking it apart in the next 2 days to see...

but whatever is, im betting to be far too large. I bought it used, i was told it came off an older BMW 2.0L engine.
It was in very nice shape, i threw a rebuild kit on it, and used it for a summer, i believe the car it came off of was located here in Denver.
What would be the jet #'s im looking for?? Anyone who has done this, and can suggest correct jets for this application
would be greatly appreciated. The Manta typically runs around Denver, and the highest elevation around Evergreen Co up in the mountains.

Thank you for your time, and help!!
Tom.
 

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Hello all,..Question (s) .....i have a 74 Manta 1.9L (stock) with electronic p/u in dizzy...
I had a Weber 32/36 on it last yr, but it was getting like 10 mpg, (no kiddin!) even trying to lean it
out was a lesson in futility. Tom.
I don't know how you could get 10 mpg with a near stock Opel engine short of flat footing it every time you got in it, and stayed in it. I'd be looking for gas leaks and checking the engine dipstick for gas mixed in with the oil.

The Solex
There may be a factory tech bulletin on jets for your situation. I think you're going to have a hard time finding the jets. I would try to figure out why the Weber was getting such poor fuel economy, it should be much easier to do than fooling with the old Solex, IMHO.

Harold
 

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Über Genius
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How did you try to lean it out?

The adjustment screw on the Weber does nothing after Idle.

Your key will be a balance. You not only need new main jets but you will need new air corrector jets as well. I don't know how the air correctors work but I'd be willing to bet you will end up with .140 mains.

Also, keep in mind that jut sizes go up, traditionally, in .05 increments but the actual change isn't as linear. The example would be that a .80 jet seems like it would be twice as much fuel as a .40 but it's actually FOUR TIMES the fuel of a .40

What this means is if you are running a .50 jet and switch to a .40, you aren't dropping by 20%. It's a bigger drop than that.
 

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tomking
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I don't know how you could get 10 mpg with a near stock Opel engine short of flat footing it every time you got in it, and stayed in it. I'd be looking for gas leaks and checking the engine dipstick for gas mixed in with the oil.

There may be a factory tech bulletin on jets for your situation. I think you're going to have a hard time finding the jets. I would try to figure out why the Weber was getting such poor fuel economy, it should be much easier to do than fooling with the old Solex, IMHO.

Harold
I had this exact problem with a SOLEX, that is 10 mpg. turned out the secondary was sticking open a bit.
 

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Discussion Starter · #7 ·
I don't know how you could get 10 mpg with a near stock Opel engine short of flat footing it every time you got in it, and stayed in it. I'd be looking for gas leaks and checking the engine dipstick for gas mixed in with the oil.

There may be a factory tech bulletin on jets for your situation. I think you're going to have a hard time finding the jets. I would try to figure out why the Weber was getting such poor fuel economy, it should be much easier to do than fooling with the old Solex, IMHO.

Harold
Harold,...a stock Opel 1.9L will barely show its tail lights to a lawn tractor, :lmao: so i have to lean into that gas pedal a bit just to stay with traffic. there are no gas leaks, no gas in oil, but i did have very black plugs, lots of black smoke out the back, and the gas gauge would drop to empty about as fast as my 71 Chevy truck does. (that tells ya something)

there are jet kits to be had easily on line, i just wanted them faster than having to order and wait on them.
 

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Just Some Dude in Jersey
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I take it that your car has the oem stock low compression unrebuilt 44 year old 1.9 engine and you floor it all the time 'cuz it's slow and now you're wondering why yer gas mileage sucks?

As Harold said, something must be really F'd up for you to get gas mileage that low. You should be getting 20-25+ mpg with a Weber 32/36.

Right off the bat I would do whatever it takes to get yourself a big valve high compression 2.0 engine, new or used. The extra 50% more power will encourage you to maybe stop driving your antique affordable economy car like a dragster.

Have you done a compression test? I think you should and tell us what you get.
 

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Über Genius
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9,401 Posts
First, thanks Harold for alerting me to my mistake above.

On the Weber 32/36, what if the pathway for the primary were blocked and he HAS to run on the secondary just to drive? Wouldn't that cause him to dump fuel down the engine?

I wonder if the carb isn't just clogged up. Too much black on the plugs to be any "normal" thing. I think it's time to check out that rebuild. Especially if an off-the-shelf Solex is working.

I ran into a situation once where one of the jets in a car was just completely loose. It wasn't doing it's job at all. Unmetered fuel was just dumping down the throat. Possibly this could be what's going on.
 
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