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Hitachi carburetor rebuild & throttle shaft bushings


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23 replies to this topic

#1 sidekickin

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Posted 17 October 2009 - 09:18 PM

Hey everyone,
I am pretty certain I will be needing to rebuild the carb on my 87 Hatchback. Symptoms: after choke kicks off, car stalls frequently when the clutch is pushed in. After the car warms up it doesn't do it as often, but as time goes by it is doing it more frequently after the car warms up too. It runs rough when it I hold the gas pedal when it is doing this stalling thing and when I let off the gas it will die. BUT, if I tap the gas pedal quickly a few times, it will go back to running perfectly and will idle great. But it will eventually go back to the stalling mode after a few times of hitting the gas. Checked EGR valve and no problems there. Sounds to me as if i have a vacuum leak in the carb, and it sounds like it might be the dreaded throttle shaft bushing problem that is so common on these Hitachi carburetors. My question is this: Do the rebuild kits contain new throttle shaft bushings or is the curburetor junk at this point?

#2 GeneralDisorder

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Posted 17 October 2009 - 10:11 PM

It's junk. The Hitachi's don't have bushings. To repair it the throttle base would have to be reamed and custom bushings installed.

Tear it down and have a look though - the shafts are brass and the throttle base is cast iron. You will probably find that it needs new shafts rather than bushings. Either way it's junk as you can't buy just the shafts.

Replace it with a Weber. There's just no point in bothering with the Hitachi's.

GD

#3 sidekickin

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Posted 17 October 2009 - 10:51 PM

Thanks GD. I was afraid of that. I guess it is time to for a Weber. Any suggestions on where to purchase one and what I should expect it to cost? Do I need to buy anything extra to make the Weber fit?

#4 GeneralDisorder

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Posted 18 October 2009 - 01:26 AM

If it were me, I would look around online, buy the carb jetted the way I want from whoever has the best price/service, then buy the adaptor plate seperate and the shorter air filter. Wouldn't be a bad idea to get an EA82 manifold at the same time and get the adaptor plate for that instead. I do not reccomed the Redline "kit" as it contains the wrong filter and nothing more than the carb with baseline 4 cylinder jetting and the adaptor plate. Personally I prefer to assemble my own kit with the right filter and adaptor and such.

After that it's just PCV hoses, block the ASV's if you have them and you're ready to rock.

GD

#5 hatchsub

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Posted 18 October 2009 - 07:45 AM

I found when shopping the bigjim (board name on here in the vendor section) had as good if not better prices on webers than other places. He works at Overseas in Vancouver Canada and i think i paid 365 before shipping for my weber. His tech support is great too as i needed some tuning in the form of different idle jets and he sent me a few different idle jets to try out. Also i would recommend his throttle shaft bearing kit to get rid of the stupid plastic bushings that are installed in webers and replace them with bearings.

#6 sidekickin

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Posted 19 October 2009 - 02:45 AM

Ouch! That is more than the car is worth! I'll have to rig something up because I can't justify putting that kind of money into the car. I've done the rig jobs on other stuff on the car, like the exhaust. Not going to spend more than the car is worth for an exhaust either. I'll buy the rebuild kit for $20, get it apart, and figure out a way to rig something to take care of the throttle shaft leak. If I can't, I am only out the $20 for the rebuild kit. I already have someone who wants the motor for an airplane if I can't fix the carb. So we'll see what happens...

#7 hatchsub

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Posted 19 October 2009 - 06:45 AM

Put a want ad up for a weber in the classifieds on here. You can probably get a used on a lot cheaper if your in a pinch. I justified spending because its my dd and im not planning on getting rid of it anytime soon.

#8 GeneralDisorder

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Posted 19 October 2009 - 08:47 AM

An '87 hatch is worth a hell of a lot more than a Weber carb. That's the most desireable body style next to the Brat. Shorter wheelbase makes them better for off-road.

GD

#9 sidekickin

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Posted 19 October 2009 - 06:51 PM

This car is probably my favorite car of all cars I've owned. It just gets harder and harder to put big bucks into it. The reason being is that I don't know how much longer the body/unibody will hold out. I live in the rust belt and there is a fair amount of rust damage to the unibody. I'd hate to spend big bucks on a repair and have the body fall apart 2 months down the road. The unibody "frame" underneath the driver's area has a hole rotted completely through which has me concerned. Floor is not rotted through, just the unibody "frame". Also, I have the mustache bar in back on the driver's side rigged up with a ratcheting strap because the unibody rotted completely off where that mustache bar mounts. Don't know how serious these things are and how much longer until the car collapses from unibody damage. The car still seems sturdy though. Any thoughts? Thanks...

#10 GeneralDisorder

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Posted 19 October 2009 - 09:59 PM

Invest in a 110v MIG welder, angle grinder, air saw, die grinders, etc and fix that rust. If you live in the rust belt and you like older Subarus/cars, it's a neccesity. Besides - it's kind of fun in a sick and twisted way.

GD

#11 hatchsub

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Posted 20 October 2009 - 06:57 AM

Invest in a 110v MIG welder, angle grinder, air saw, die grinders, etc and fix that rust. If you live in the rust belt and you like older Subarus/cars, it's a neccesity. Besides - it's kind of fun in a sick and twisted way.

GD


Yea..fun :rolleyes: Wanna send me over a rust free car there lol. I got more rust than i care to mention...even though im going to be taking pictures soon and posting them. Im playing with a new welder and its coming out decent actually.

#12 Quidam

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Posted 20 October 2009 - 10:38 AM

Hi,

You didn't say which engine or carburetor you have on the hatch...

Rebuilt Subaru "throttle chambers" are available. Rebushed shaft and all. Try rupair in Boulder Co., about $75.00 I believe. That is, if you need one.

Complete remanufactured Hitachi carbs show up at discount with ebay too. $200.00 or less at times.

If you rebuild one, I recommend you get a new power valve as they don't come with any kits I know of.

Just some thoughts for consideration. The Hitachi is not so bad when it's right.

Whether Weber or Hitachi reminds me of the old Holley or Rochester disputes. The Rochester Quadrojet is a good carb too, when it's right.

Have you ever installed a kit in a carburetor? Sounds like you need this to be low budget.

Doug

Edit: Does your Hitachi look like this inside? http://www.ultimates...&pictureid=1747

Edited by Quidam, 20 October 2009 - 11:00 AM.
Add picture.


#13 GeneralDisorder

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Posted 20 October 2009 - 11:19 AM

The main problems with the Hitachi (as I've noted many times), is that they used a complicated system of vacuum valves and thermo-valves to regulate airflow to the air correctors. This was done to accomidate the feedback models with the ECU. The non-feedback are the same though - just jetted differently.

Also the vacuum operated secondary is not very sporty to drive.

The Webers are simpler, more fun to drive, and easier to rebuild/get parts for. Yes the Hitachi's are reliable when properly rebuilt but they will never have what the Weber's offer.

GD

#14 sidekickin

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Posted 21 October 2009 - 12:36 AM

The hatch has the EA-81 in it. As far as which Hitachi, I don't know. It is 4WD and has no ECU or oxygen sensor either. I see 2 Hitachi rebuild kits listed. Not sure which one it will be. Unfortunately, the serial number was wiped off when I did a good engine degreasing years ago when I bought the car. Those carbs must be made out of soft metal. Out of curiosity, I was wondering why the 4WD hatchbacks get much worse gas mileage than the 2WD hatchbacks. I have come across old magazine advertisements for the 2WD hatchbacks claiming mid 30s to low 40s for gas mileage, while my window sticker for my 87 4WD hatch says 24 city / 28 hwy. Was wondering if this is a carburetor difference between the 2WD and the 4WD or if it is just the extra weight that contributes to that significant drop in mileage. I'm sure some of it is due to the extra weight, but a 15 mpg drop in mileage is pretty significant. I'd love to get mileage in the 30s for my car if it would be possible. I average about 25 mpg. Are the Webers more fuel efficient?

#15 GeneralDisorder

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Posted 21 October 2009 - 06:19 AM

Your Hitachi is a DCP-306-7xx. Probably a 721. Irregardless, all of the DCP's use the same rebuild kit. The EA82's use the DCZ carbs.

As for mileage - the 4WD's get worse mileage because of the gearing, the tire size, and the weight. Mostly it's the gearing though - the 2WD's had 3.7 final drive ratio and smaller tires, while the 4WD's have 3.9 and larger tires.

The carbs *are* jetted differently, and most of the 2WD's also had the feedback computer controlled versions. But the difference is like 1 or 2 MPG between the 4WD non-feedback and the 4WD CA spec models. It's not at all worth the hassle of that system.

I routinely get 26 with my Weber in mixed driving. On my last trip to the beach I got 31.5 on my 4WD hatch with the Weber. I just drive normally - I don't try to get amazing mileage or anything. And my engine burns a lot of oil and has one cylinder with low compression. I tuned it with a wideband O2 sensor though. It's getting an EJ22 very soon so I haven't bothered to put any work into the engine.

Be glad you get high 20's. I get 16 in my turbo legacy :rolleyes:

GD

Edited by GeneralDisorder, 21 October 2009 - 06:21 AM.


#16 Quidam

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Posted 21 October 2009 - 11:30 AM

"Unfortunately, the serial number was wiped off when I did a good engine degreasing years ago when I bought the car. Those carbs must be made out of soft metal."

Well the serial number...For want of a better description, the ones I've looked at seemed to be printed in ink. Not durable at all.

Soft metal? Don't know what that means. With old carbs the metal can deterioriate, along with the finish. I've never been able to refinish a carb at home. If it's that bad I'd just replace it. If it's that bad and the throttle shafts are worn too, well, you don't have much left but a core. Often you can't just put a kit in one and expect it to function as designed.

With a reman carb you just bolt it on and go, you'd be good for years.

Here's a DCP-306-21 for instance. http://cgi.ebay.com/...&category=33550

BTW, the throttle/base plate would cost me about $100.00 shipped.

But compared to this at RockAuto:

1987 SUBARU GL 1.6L 1595cc H4 2BBL (2) : Fuel/Air : CarburetorPriceCoreTotalPosted ImageUNITED REMAN. Part # SUB169
w/Plas. Choke; Fed. Mdl.
Hitachi; Exc. Calif.* Non-stock item--shipping delayed up to 2 business days$456.79$75.00$531.79

It's not so bad.

Anyway, hth. with decisions.

Doug

#17 Dinky26

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Posted 19 July 2013 - 09:15 AM

So sidekickin, what did you end  up doing with your carb on this issue?

 

Did you go ahead and replace it with a Weber?

 

Any idea how many miles you had on that carb?

 

Just wondering cause mine is starting to have starting issues, but once I get it running it is fine.  I am just concerned with the throtle bushing detail you explained on yours, having mine do the same thing 5000 miles down the road after I rebuild this Hitachi.



#18 Gloyale

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Posted 19 July 2013 - 11:40 AM

90% of the carbs I rebuild have a little play in the throttle shaft.  It's not really an issue unless it's ALOT of play.

 

Unfortunately, Ive not been able to find a repair option for the throttle shafts.....so if they are too bad it's a junker.

 

The upside is these carbs are fairly easy to find.....or used to be, getting harder as everyone throws them away and gets webers........then they have issues with the weber too.

 

I personally love the hitachis, and will take any and all that anyone wants to get rid of.



#19 turbosubarubrat

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Posted 19 July 2013 - 12:16 PM

So sidekickin, what did you end  up doing with your carb on this issue?

 

Did you go ahead and replace it with a Weber?

 

Any idea how many miles you had on that carb?

 

Just wondering cause mine is starting to have starting issues, but once I get it running it is fine.  I am just concerned with the throtle bushing detail you explained on yours, having mine do the same thing 5000 miles down the road after I rebuild this Hitachi.

he hasn't been on the board since january and i remember his hatchback got rear ended to where all the back glass broke and the wheel wells where stuck to the back wheels or close to it. the last time i saw him on here he was fighting the insurence companies to get more than a  a couple hundred bucks for his hatch which he gave up and excepted the low offer to just get the hatch and part it out then scrap it.



#20 Dinky26

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Posted 19 July 2013 - 12:56 PM

90% of the carbs I rebuild have a little play in the throttle shaft.  It's not really an issue unless it's ALOT of play.

 

Unfortunately, Ive not been able to find a repair option for the throttle shafts.....so if they are too bad it's a junker.

 

The upside is these carbs are fairly easy to find.....or used to be, getting harder as everyone throws them away and gets webers........then they have issues with the weber too.

 

I personally love the hitachis, and will take any and all that anyone wants to get rid of.

 

I am all about recylcing whatever possible.  I hate it when people throw perfectly, or near perfect stuff away.

 

My Weber will be in town on Monday, so if you'd be willing to give me $60 I'll ship it to you, once I get my Weber up and going.



#21 Gloyale

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Posted 20 July 2013 - 10:29 AM

It will fit in a $15 FLAT RATE BOX.

 

Why would shipping for a 3 lb item be $60???



#22 Dinky26

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Posted 20 July 2013 - 04:35 PM

So you want to pay $0 for the carb itself???

#23 Gloyale

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Posted 20 July 2013 - 04:41 PM

As the alternative to it being thrown away

 

I got enough Subaru parts I don't need more but i'll take it if your trashin it.

 

Sorry, didn't mean to give the wrong impression.



#24 Dinky26

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Posted 20 July 2013 - 11:22 PM

I probably just read to much into what you wrote, I'm sorry too.

I'll keep your offer in mind.




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