Solex Carburetor Problem

[frassum]

Hello,

I've got a 1974 Manta with a stock solex carb. I hadn't started it in about a year and when I tried, the motor would not idle. If I applied the throttle, the motor would stay on. Once the motor warmed up, it idled, but very poorly. When I took it for a drive it ran ok at speed, but when I came to a stop, the motor would occasionally die. I could start it up and give it the gas and it would go.

I'm about to do a carb rebuild, but would appreciate any advice offered.

Thanks,

John

[First opel 1981]

Originally Posted by frassum Hello, I've got a 1974 Manta with a stock solex carb. I hadn't started it in about a year and when I tried, the motor would not idle. If I applied the throttle, the motor would stay on. Once the motor warmed up, it idled, but very poorly. When I took it for a drive it ran ok at speed, but when I came to a stop, the motor would occasionally die. I could start it up and give it the gas and it would go. I'm about to do a carb rebuild, but would appreciate any advice offered. Thanks, John

First advice is put a weber on.
If you don't want to go that route then get a can of Gumout (not another brand) carb and choke cleaner and use the whole can, following the instructions. A Solex carb won't operate properly after sitting for a year without being cleaned very well. I would also suggest some fuel injector cleaner in the gas tank.

As for the solex. I had that problem on #1 GT and it turned out that different brands of gas would cause different properties of carbureation. I could buy generic gas and it would idle but it wouldn't idle with Texaco gas, and so on.

My original advice though, install a weber, is still my best advice.

[Opelkurt]

Before you rebuild anything-

1) Check carefully for vacuum leaks; vacuum hoses can deteriorate and crack over time.

2) Check the brass jet that screws into the outside of the primary (outboard) barrel, I think it's call the idle air jet. It's easy to unscrew and clean; 99 times out of 100 when I've had problems like you've described, I've found this jet to be plugged at the tip. When a Solex sits for some time, crud forms in the fuel passages and tends to plug that jet. Be careful not to strip the threads in the carb body.

-Kurt

[Dennis Texas]

Originally Posted by Opelkurt Before you rebuild anything- 1) Check carefully for vacuum leaks; vacuum hoses can deteriorate and crack over time. 2) Check the brass jet that screws into the outside of the primary (outboard) barrel, I think it's call the idle air jet. It's easy to unscrew and clean; 99 times out of 100 when I've had problems like you've described, I've found this jet to be plugged at the tip. When a Solex sits for some time, crud forms in the fuel passages and tends to plug that jet. Be careful not to strip the threads in the carb body. -Kurt

Ditto

I would definitely stick with the solex, I feel they are better carbs then the weber. Check the gasket, carb to manifold, and be sure not to overtighten the base nuts when you go back with it. Snug is sufficient. If you haven't changed the points to electronic ignition yet put that at the top of your list for better spent money and stick with the solex.

[Anonymous D]

I don't agree.

The Solex carburetor is prone to numerous operating problems, many deriving from heat warpage (because it's bolted to an intake manifold that sits right on top of the heat stove of the exhaust manifold). Precise tuning is difficult. Example: The factory manual calls for a water manometer to set the throttle place calibration. Got one? The accelerator rod was also redesigned (as found in a parts kit issued later). Got one of those?

The Weber is an easy conversion. Yes, any carburetor on an Opel will also require you to eliminate any possible sources of a vacuum leak (hoses, seals), but once that is done typically the Weber is also far easier to tune (idle speed, choke idle, and idle mixture = 3 screws). Compare that, to the many pages of Solex tuning instructions (issued in Tech Service Bulletins by Buick/Opel in the 1970's).