Subaru carbie woes

[nilla60]

SWMBO's 1991 L series Subaru was beginning to splutter and complain bit when starting, so I suggested to SWMBO that the carbie was probably due for some attention.

In short, local mechanic agreed and as a bit of carbie cleaner improved matters, SWMBO agreed with his suggestion of sending the carbie away for an overhaul. We've used him for years and he's a good bloke.

Since coming back, the throttle has been sticking a bit and the fuel consumption has been crap. The local mechanic has pulled the carbie out (twice) and tried to loosen up the sticking with some WD40. Apparently they carbie people told him that the carbie was sticking because it's worn.

Ordinarly, that'd seem reasonable enough to me, but the bad economy suggests a bodgy job. I'm wondering if maybe the sticking shaft isn't so much worn as bent.

Is this sort of outcome unusual for petrol motors? Is it reasonable to expect sticking as a normal impact of ordinary wear & tear? Is it worth insisting the carbie place make this good, or is beter to find a new carbie?

[trains]

try loosening off the nuts around the base of the carby, and retensioning them evenly.

Check that all the cable and workings of the carby are as they should be, and you dont have a rubber boot off the cable fouling the linkages etc.

T

[minisman]

if what trains said doesn't work, I'd be getting that carbie mob to sort it out. If they are rebuilding a carb, it would want to be in perfect working order before you pay money.

But with my experience with Subbies cables, autochoke and the butterfly spring could sometimes make the throttle stick

[Tree cutter]

I would say the choke is sticking shut a bit. This would cause both bad fuel economy and a high idle speed. Send it back to the bloke that rebuilt the carby and tell him what it is doing.

[nilla60]

Hi Tree Cutter, thanks for that it turned out to be the automatic choke. Some adjustment seems to have fixed it. We'll see how the fuel economy goes.

[HiFiRobbie]

Since coming back, the throttle has been sticking a bit and the fuel consumption has been crap. The local mechanic has pulled the carbie out (twice) and tried to loosen up the sticking with some WD40. Apparently they carbie people told him that the carbie was sticking because it's worn.

I'm wondering if maybe the sticking shaft isn't so much worn as bent.

Is it reasonable to expect sticking as a normal impact of ordinary wear & tear?

Invariably, NO!

The whole idea of overhauling a carburettor is to bring it back to, or better that brand-new!!

If the carburettor has been properly overhauled and not just stripped and re-built, the shaft tunnels in the base should have been cut and re-bushed and it should probably have had a new throttle disc fitted too. Worn throttle discs cause end-float in the throttle shaft and are often the cause of a lot of idle problems.

Even if the shaft was slightly bent upon re-installation, it is not that difficult for an experienced tech to straighten it.

As far as the consmption goes, I have "repaired" several carburettors that had the main jets in the wrong way around (Primary in the Secondary and vise-versa) but this is not physically possible on many units. It could also be an air corrector fitted into the wrong orifice. This could be a headache to rectify as sometimes there are 3 or more possible places they can go.

Glad you got the sticky throttle sorted though, that's the really dangerous one.

Cheers,

Robbie

[nilla60]

If the carburettor has been properly overhauled and not just stripped and re-built, the shaft tunnels in the base should have been cut and re-bushed and it should probably have had a new throttle disc fitted too. Worn throttle discs cause end-float in the throttle shaft and are often the cause of a lot of idle problems.

We also ended up getting a replacement throttle disc from a wreckers as there weren't any new ones available.

Thanks for the info!

[Ben78]

Get yourself some Upper Engine Cleaner from a Subaru Dealer and follow the instructions on the can, fixes a ton of idle roughness problems caused by coked up valves on the old EA engines. My brumby went from pinging at any throttle over 4k when I got it, to clean smooth redline, plus it idles smoother and at lower rpm and has more power. But, I didn't rebuild the carb either!

(source: 13 years of driving EA engined subarus all s**tboxes that I worked on lovingly, except my current brumby which will bring a tear to my eye when it gets driven away for the last time, such a nice car)

Reminds me, I need to get a can of the stuff for my H6 outback...

[nilla60]

Should be OK as she got the heads machined and crack tested when it did a gasket last year. Sounds like a good preventative though. Thanks.

[Ben78]

Crack tested hey? Even if they said they weren't cracked they would have been. They crack between the valve seats. Subaru has a tech bulletin on it, it says to punch the cracked area with a pin punch HAHA. When they machined the heads what did they do to make the inlet manifold line up and advance the cam timing?

[nilla60]

Not a clue, but it's been good since, no oily residue build up in the coolant and no more overheating (and I was fine about not having to buy new heads). SWMBO took a 2003 Outback for a test drive last week and its gaskets had been replaced under warranty with a revised design. You'd think they'd have worked out a head that doesn't pop by now (but she's getting a Subie anyway).

[nilla60]

Update. We cracked the s**ts and took the carby to another carby shop who re-bushed the shafts with teflon inserts and it runs really sweet now. Less than $200.

[HiFiRobbie]

Glad you finally got it sorted Nilla!