New or reconditioned Carb

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Hi,

I am new to this forum, but I am restoring a 1988 23ft sport's boat with a small cuddy cabin and a 4.3L OMC King cobra petrol engine. I found it in a field a few miles from home.

I do not know who manufactured the boat, possibley a Sea ray or simular, But I need a replacement carb or the original reconditioning as it was supplied in pieces.

The carb is a four barrel rochester, Anyone know where I could get a replacement?

Also I am the aftermarket Manager for Cummins Onan, as some people will know we supply marine generators to some of the boat builders and before anyone ask's. No we do not get any s/h gensets.:)

But if any one would like any advise? that's not a problem.

Regards Anthony
 
i did my qudrajet myself pritty straight forward if your good with the spanners.
you just need to order a rebuild kit.the jets are numbered you will need to open up the carb to find out what size they are.
i have purchased a rebuilt carb from the u.s.a.but when i got it the threads on fuel inlet were stripped(still got the carb somewere) so if you do go for a recon try to get one from a good source.i dont think their is a massive saving between recon and new,so new would be my first option if you can'nt rebuild the one you have..
 
Quadrajets are pretty simple. Just get yourself a rebuild kit for your carb using the model number. On my Qjet it was stamped on the rear of the right side if looking from the front (where the fuel inlet is). They usually start 70XXXXX or 170XXXXX depending on the age of the carb, being a late 80's boat is should be 170XXXXX.

This is where the model number is on mine:

The number is 17082526 on mine.

So long as the tubes on the air horn (the top bit) haven't been bent or crushed you should be ok. I do recommend you also get a replacement brass float at the same time as they are pretty cheap and the plastic ones are liable to absorb fuel after time as mine did a few weeks ago.

If it's not a "modquad", which yours should be if it's a late 80's carb, you would be well worth epoxying the bungs, as these are liable to leak on older quadrajets too.

Normally I'd recommend photographing the carb as you dismantle it, so that you can reassemble it by reversing the pictures but as you won't have that luxury I've uploaded mine which may help you.

http://s292.photobucket.com/albums/mm28/BigD77uk/Chevy Nova/Quadrajet/

The good thing with having it apart and building it from scratch is that you can get the secondaries set up nicely before it goes back on. A lot of the time the mechanical part doesn't open the secondaries fully, however that's easy to sort. Take your throttle plate and using your finger open the secondary butterflies (they are the big 2 at the back). When the can't move anymore they should be at 90 degrees to the throttle plate. If not, on the left hand side of the plate you'll see a bar that turns with the secondaries and touches a stop, bend that bar until the secondaries are at 90 degrees when the bar touches the stop. Next turn the plate on the right front that the throttle cable usually attaches to, the primary butterflies will open, then at about half way round the secondaries will open. When you can't turn that plate any more the secondaries should again be at 90 degrees to the throttle plate, if not there is a link that goes between the primaries and secondaries, you'll need to bend this to adjust it's length until the secondaries are at 90 degrees at full throttle. Job done :)

This is the pin and stop on the left

The carb was pretty built in this image so ignore the tarnished lever, that stops the secondaries from opening when the choke is on. The bit you are interested in is the silver bar that goes through the green shaft on the left of the image. Directly underneath the shaft is the stop, it's square one side, sloped the other. This was before I adjusted mine, the very left side of the pin is now bent so that the secondary butterflies open to a perfect 90 degrees.
 
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Thanks for all of the information.

I am going to try a rebuild kit from the USA, If it does not run great with this. I will buy a reconditioned unit.


Regards
Anthony
 
Try a company called Rodley Motors, they are in the North of England and are importers of American car parts, including parts for OMC engines, they also do marine components like carbs.
They might even rebuild yours.
 
hi are
your carb will be a rochester 4me four barrel, two stage, down draft carb, your engine and mine were supplied with the one menctioned, i have the the nikki carb there is also a holley 2010.

The vovlo penta manual has all the info you will need the book is for AQ205,430,431,432,434. if you can pm me a fax number i will copy all the info from the book and fax it to you when im off from work on tuesday so then you will have a hard copy, i am looking at the moment at a full diagrame of parts assembly, the book also shows overhauling and checking and assembly, also fault traceing.

I understand from previous dealings with these carbs that there are very very time consuming and difficult in setting up and getting the vacum and settings set right.

do a search online you will find spares, here one

http://www.carbkitsource.com/carbs/tech/Rochester/Quadrajet-index.html



mark
 
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I have to disagree with the setup being hard, it's just that a lot of people don't know how to adjust the spring resistance on the secondary flaps, they usually set it too loose so the engine bogs when it's floored. Its pretty simple to adjust, easiest when the carb is out.

Looking down on the carb, fuel inlet pointing away from you, follow the shaft from the secondaries air flap right til you get to the edge of the carb. You'll see a square section sticking out, underneath that is a small hex bolt, and if you look from the right of the carb at the square section, move the air plates with your finger and you'll see a small screw. Basically undo the hex bolt and it allows this screw to be adjusted. With the carb upside-down look inside that square area and you'll see a spring and it's attachment to the secondaries air flap shaft. Turn the screw until it just touches the pin coming out of the shaft, then tighten the screw a further 3/4 of a turn, tighten the hex bolt with the screw in that position and it's set.

Quadrajets are fantastic carbs capable of 800cfm (depending on the model) which is good for up to around 600bhp, but being a mechanical secondary spreadbore carb they're also great for economy.
 
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Assassin said:
Try a company called Rodley Motors, they are in the North of England and are importers of American car parts, including parts for OMC engines, they also do marine components like carbs.
They might even rebuild yours.
Click to expand...


Thanks, I know the owner of Rodley motors as I have repaired a few RV generators for him,

I will give him a call.

Anthony
 
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