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Posted By: DavidB Carburettor rebuilds? - 27th Nov 2013 1:41pm
Does anyone know of any experts on the Wirral that can do decent rebuilds on carburettors?

I have an old Subaru which has a carb - the carbs on these are reknowned for their awfulness, and would like to get it rebuilt.
It has been rough and getting worse. It's completely drivable, but the revs are 2,000rpm - 3,000rpm, and I can't cure it, even after taking the carb to bits, cleaning it and putting it back together again. The jets look fine.
The car is taxed/MOT'd and can be driven to the garage etc.
Posted By: s7uajones Re: Carburettor rebuilds? - 27th Nov 2013 10:54pm
Hi there carb experts are hard to find these days
However I have some experience from my vauxhalll nova days

A carb works on air and fuel, open the throttle and more air is pulled in and sucks fuel with it. ,,, so you could have an air leak on the base of the carb or on the inlet manifold.
Take some wd40 and spray it around those areas and if the engine note changes thefts the problem
Hope this helps
Stu
Let me know how you get on
Posted By: turnip Re: Carburettor rebuilds? - 28th Nov 2013 6:50pm
Which model and engine code/size is it? Usually these are fitted with the Hitachi carbs.

All carburetors except the C-W are 2-barrel down-draft carburetors which supplies the best air/fuel mixture under any operating condition. this is effectively similar to the ubiquitous Weber design.

The C-W is a single barrel carburetor.

The two barrel carburettor uses a progressive linkage between the primary and secondary circuit. So ... first question ...Is the secondary side butterfly of the carb operating correctly? When you depress the accelerator pedal to the floor both the primary and secondary butterfly's should be fully open.

For optimum performance plus fuel economy, the secondary circuit of the carburetor is used only at high engine rpm. Normal low speed operation is handled by the primary circuit (from idle to approx 2500 - 3000 rpm).

Posted By: turnip Re: Carburettor rebuilds? - 28th Nov 2013 8:19pm
sorry, just seen the bottom of your post "C20"

WHICH IF MY MEMORY SERVES ME CORRECTLY IS A FORESTER?
Posted By: DavidB Re: Carburettor rebuilds? - 28th Nov 2013 9:45pm
Lol, no the C20LET is a Vauxhall engine (from a Calibra/Cavalier turbo) smile.

The engine is a Subaru EF12! It has a Hitachi carb, which is two barrel. The primary opens on a lever from the pedal, but the second opens using a vacuum from a dashpot - I've tested the dashpot by blowing into it and the lever moves.
The car moves well, even on full open throttle - I believe it is running much better now than when I got it, but it just isn't idling correctly (which is now making me think there IS an airleak like su7ajones says), or something isn't working. I bought some easy start and will try it out tomorrow.

The carb has a duty solenoid which opens a valve in the carb which controls the fuelling/slow air bleed inside. These are known to be dodgy I think.

After running the engine for 20 minutes while I messed around, I revved the engine to 8,000rpm (it's a 3 pot 1.2), and it got there as normal ...
I can tolerate the naff starting (requiring depressing the pedal slightly), and the slight hesistation (esp around corners - fuel starvation?), but the rpm makes it silly to run.
Thanks for your help!
Posted By: DavidB Re: Carburettor rebuilds? - 28th Nov 2013 9:50pm
Just thinking, I'll have to check the ignition timing as well - you can only check this at 800rpm correctly, but will try it out as I did it a few weeks ago when it wasn't running well at all.
Posted By: DavidB Re: Carburettor rebuilds? - 21st Dec 2013 4:52pm
Still have this - converted to manual choke. Have removed the autochoke as it was making a bad situation much worse. It runs, drives, etc., but it's very lumpy. It's overfuelling a massive amount which is what I think is the only problem tbh. I've changed the mixture screw, but it makes no difference. Screwing it right in and it's still running?
I can't believe nobody services carbs anymore.
Posted By: sean Re: Carburettor rebuilds? - 23rd Dec 2013 12:08pm
3 pot, 1.2? I take it that is a justy then? bin it a put an EJ20 in wink
Posted By: DavidB Re: Carburettor rebuilds? - 25th Dec 2013 1:00am
Yes, it's a Justy.

The EJ20 would never ever fit in the ... oh ...

http://carphotos.cardomain.com/ride_images/3/2654/2121/31633560004_large.jpg

http://www.cardomain.com/ride/3163356
Posted By: turnip Re: Carburettor rebuilds? - 31st Dec 2013 12:05am
swap the stock Hitachi for a Keihin from an old Honda Civic 1.3, you have to widen 2 of the 4 mounting holes as the keihin has a slightly different base pattern but by all accounts it is an effective mod. found it on internet!
Posted By: DavidB Re: Carburettor rebuilds? - 11th Jan 2014 7:56pm
I heard the Keihin fitted as a few people have put the carb off a Honda 1.5 on. Also the Toyota Corolla 1.3 fits without much modification. I will buy one if I can find one! Thanks for the help!

I basically completely rebuilt the carb, made new gaskets, and flushed the whole thing through with a whole tin of carb cleaner and put it on (with the manual choke still on).
It started and ran, but the choke pull off obviously wasn't working as the autochoke controls it. I had to have the choke open all the time, and occasionally turning the car off, let it run on for about 3 seconds with a unbelievably loud bang from the exhaust.
Removed the silly manual choke conversion, and thinking it's kind've working OK, I put the autochoke back on, and finally got it running after about 10 minutes of setting up and new vacuum hoses. I've done about 30 miles in it today, which should say it's running good now. smile

Considering what it was like, with fire literally shooting out of the top of the carb, and black smoke from the exhaust (with the odd backfire). smile
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