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Need some advice on carb swap


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I recently purchased a rebuilt Hitachi for my 87 GL wagon because of carb issues from carbsonly.com and am planning on swapping it out this weekend. I know I should of went with a Weber but just don't have the money right now. Other than making sure I connect all of the vaccum/fuel lines up correctly what should I be concerned with? Also once I get everything connected what am I going to have to adjust to get it running like it should? I am sure this is a stupid question but this is the first time I have done anything with a carburetor and just want to make sure I do it right. Any advice would be much appreciated.

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Check carefully all the Vacuum Hoses, where they come from / where they go, `cos some of them are critical in Hitachi carbs. For example: the secondary stage on a Hitachi is activated by a Vacuum, if you don`t connect the correct hose there, you can finnish with one of this Three posibilities: 1) A permanent Vacuum = Always acceleratin` to Redline. 2) No Vacuum = No Secondary Workin` so, your car will become Slow and Unpowered. 3) Wrong Vacuum = May activate the Secondary in the Wrong Moments... :slobber: ...And that`s the posibilities with just one of the many vacuums of the Hitachi...

 

Are you Sure that you`ve Purchased the Right Carb. for your Subie? `cos slighty Different Carbs. can perform poorly... (I tried with a Nissan one... It was a Nightmare!) ...or suck much Gas... Be Careful.

 

 

I recently purchased a rebuilt Hitachi ... I know I should of went with a Weber but just don't have the money right now ...

 

Maybe in the Future you Can obtain a Weber... is Better Idea. Weber = No Vacuums (Execept for the one that goes to the Dist. Vacuum Advance)

 

Good Luck! :)

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I am almost positive that I got the right carb. I will just go ahead and mark each hose to the corresponding inlet on the carb that way as to ensure correct hookup. Thanks for the advice. Anyone else have any first hand experience to pass on?

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Vacuum secondary is a small hose from one part of the carb to another - you won't have to touch or mess with it in any way.

 

Make sure you use NEW gaskets between the base and the plastic spacer, and between the spacer and the carb. And make sure you use gaskachinch on them (it's made my edelbrock - it's kind of like plastic cement) or you will have a coolant leak. Prep the surfaces really well with a razor blade scraper, and a wire wheel.

 

While you are down there, replace the small 1/4" coolant hose from the thermostat housing to below the carb - 1/4" fuel line will work.

 

And drain about 1/2 of the coolant out before you remove the carb, or you will have a mess on your hands.

 

GD

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also when doing the swap make sure that the gasket surface that your mating the carb to (the intake in other words) is really clean of anything and flat. Otherwise your new carb wont run right cause of a huge vacuum leak under the carb. Other than that..mount it..start it..adjust the idle screw..adjust the choke if needed and adjust the mixture. you should be golden after that.

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Make sure you use NEW gaskets between the base and the plastic spacer, and between the spacer and the carb. And make sure you use gaskachinch on them (it's made my edelbrock - it's kind of like plastic cement) or you will have a coolant leak. Prep the surfaces really well with a razor blade scraper, and a wire wheel.

 

GD

 

hmmm i just installed them dry and havent had a problem yet that i know of. Maybe i got lucky.

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Oh yeah - tuning:

 

If it's been profesionally rebuilt *correctly* you shouldn't have to mess with ANYTHING except the idle speed screw. The idle mixture is not supposed to be adjusted, and the choke is held in place with a brass pin and riveted - it should not be moved either.

 

That said, it may be neccesary to change things as often rebuilds on these are difficult, and it's not uncommon for those rebuild places to screw something in too lean or something.

 

GD

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hmmm i just installed them dry and havent had a problem yet that i know of. Maybe i got lucky.

 

You can - but they are just cardboard, and the material likes to absorb coolant and eventually fail - similar to the cheap aftermarket manifold gaskets. If you coat them first they are usually fine, and as a side benefit, the gaskets will come back off clean even years later using that stuff. So if you have to remove it for some reason it won't destroy the gaskets.

 

GD

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Any decent parts store should have it, or a similar product. It's in a can that looks just like the rubber cement that smelled oh-so-good back in grade school. It's a red can with the edelbrock logo.... Baxter's auto parts has it around here, but I don't know if you have them where you are.

 

Heck - you could probably just USE rubber cement.... it smells very similar. :confused:

 

GD

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GD: you're just talking about giving the gasket a rubberized cladding like you do with the oilpan gaskets, right? that just makes gasket sense :-p

 

Yeah - basically. I coat lots of my gaskets, except for the graphite/metal stuff like HG's and intake manifold. If it's cardboard, I feel it needs something gooey on it :lol:

 

But - it's very important for things like the oil pan that the sealant be allowed to dry before it's installed or bits could get sucked into oil passages and wreak havoc.

 

GD

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You could order some OE carb base gaskets from Eurospecparts.com ,,,very cheap price and much better quality then what comes with the rebuild carbs...

You can - but they are just cardboard, and the material likes to absorb coolant and eventually fail - similar to the cheap aftermarket manifold gaskets. If you coat them first they are usually fine, and as a side benefit, the gaskets will come back off clean even years later using that stuff. So if you have to remove it for some reason it won't destroy the gaskets.

 

GD

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