Anyone here rebuilt a Quadrajet?

S

shore

New Member
Jul 18, 2009
439
port orange florida
Boat Info
1996 290 Sundancer
Engines
Twins and a Gen
I think I'm gonna tackle this.I need to order a rebuild kit but it's kinda hard when the boat is in storage.

Can I just get a rebuild kit from an auto parts store or do I need to order one online?

My engine is a early 90's 330hp 454.It's not the original engine in the boat.
 
Unless you have A boil tank I wouldn't try it there is alot of small Idol passages that need to get cleaned thru the dip tank , just pul the carb and take it to the carb shop
there are a lot of small parts it's not like a holly
 
tomk said:
Unless you have A boil tank I wouldn't try it there is alot of small Idol passages that need to get cleaned thru the dip tank , just pul the carb and take it to the carb shop
there are a lot of small parts it's not like a holly
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:thumbsup::thumbsup::thumbsup::thumbsup::thumbsup:

Jack
 
I rebuilt a Quadrajunk once, (used a boil bucket and rebuilt it by the book), it belched raw fuel on the engine of my 73 Nova SS and caught fire. I'm with tomk, carb shop...
 
+1 on getting the carb rebuilt by a professional.

I'm a pretty good shade tree mechanic, but the carbs I've tried to rebuild were disasters. In fact carbs and transmissions are on my list of pay someone else to do it.
 
just did probably the identical carb over the weekend, 89, 454, 330hp 841.00 thru Merc? had a low hour and put it on the boat, it spewed and i had no choice to bust it down at the boat, i was 75 miles away and no way was i coming all the way back.
tore it down on the picnic table...im a trannyman, and i always strayed from carbs because tranny's boggle my mind enough, but alls well ended well, i must of flipped the carb at one time and the needle float fell out.
got it back together and installed and its like a new boat, i was very surprised...the boat idles nicely now at 650, does not stall when put in gear, and when i powered the boat up i could hear the rope creeking.
its about a 7 on the technical scale and one thing i do recommend if you dive into it is...take some pics. i got thru it, watch for play on the shafts because if they are worn they will pull air.
 
I had 2 that had throtle shafts worn out. Having been a auto mechanic for 37 odd years and working on quadrajets I found out that replacing them with the Holley direct replacement unit's works best. Now how much? well I searched Ebay and found new ones for half price. Part number 0-80552 Model 4175. They are 650CFM's. I'm getting better gas milage and the engine runs smoother.
I had a 268 sundancer before getting the 340. It had a 350 in it and I installed one on that.Again smooth running and great mas milage.
Do the research and save. The 454's also seem to start easier. 1 pump and it fires. It was (to me) worth the money.

Rick
 
I have rebuilt 200+ Q-Jets in my life. They are not that hard to do. You will need the number off the carb. If you are unsure of the number take it to the parts house with you and the can get you the correct kit. The best kit to get would be Hygrade kil. For safe insurance I would highly recommend replacing the float. (Does not come in the kit.) You can get a book to help guide you along. You may also contact me if you have any questions 850-257-9511 anytime after 11am. I would gladly help you out. I can rebuild it for you as well. Wayne
 
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Relatively simple carb. If your somewhat mechanically inclined, have good common sense, patient and can follow directions you'll be fine. What issues are you having?
 
Long cold start but that may be choke related since it's off but it is very warm out.

I also have a slight pop through the carb under full throttle acceleration.

We had a very clogged fuel filter at 1st.The boat would not get past 3k.The fuel filter in the carb inlet was nearly plugged.Cleaned that out and she ran decent but still had a slight pop through the carb when you put the stick down.

our decision was the accelerator pump was leaking.We took the horn off and my friend said the pump was weak at best.We just didn't have a kit at the time to do it.
 
Oldsman said:
I have rebuilt 200+ Q-Jets in my life. They are not that hard to do. You will need the number off the carb. If you are unsure of the number take it to the parts house with you and the can get you the correct kit. The best kit to get would be Hygrade kil. For safe insurance I would highly recommend replacing the float. (Does not come in the kit.) You can get a book to help guide you along. You may also contact me if you have any questions 850-257-9511 anytime after 11am. I would gladly help you out. I can rebuild it for you as well. Wayne
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What would you charge if I sent it to you and how quick could you get it back to me.You would have to buy the kit so take that into account.

tgriffin36@cfl.rr.com
 
I agree with Oldsman. I've done hundreds of them as well back in the day. Get a hygrade kit, a float, and a couple cans of spray carb cleaner. Boat carbs are relatively clean compared to the auto stuff - less gunk around them - so pretty easy to clean up. Use the carb cleaner spray tubes to spray into all the little holes and orfices. Let it soak, do it again. I think it works better than a soak tank. Then rinse with water. If you have compressed air, spray that through all the holes and orfices.

There aren't that many parts, and they aren't that hard to put together. No special tools required, other than float drop, and that guage comes with the kit. If you pull the idle mixture screws, just remember how many turns to bottom so you can put them back as they were.

Out of curiosity - what is the carb doing that requires a rebuild?
 
Sorry - just saw your note on the issues.

Long cold start - could be choke - or could be the fuel bowl leaking down causing the fuel pump to have to fill the bowl first.

Pop on acceration - I would look at ignition related items first.

Accelerator pump failure generally leads to a bog or hesitation on acceleration, not a popping.

Did you measure the pump pressure with a fuel pressure guage?
 
Oldsman said:
I have rebuilt 200+ Q-Jets in my life. They are not that hard to do. You will need the number off the carb. If you are unsure of the number take it to the parts house with you and the can get you the correct kit. The best kit to get would be Hygrade kil. For safe insurance I would highly recommend replacing the float. (Does not come in the kit.) You can get a book to help guide you along. You may also contact me if you have any questions 850-257-9511 anytime after 11am. I would gladly help you out. I can rebuild it for you as well. Wayne
Click to expand...

Don't forget to epoxy the well plugs, Known problem is well plugs leaking and also the primary tubes fall off into the bowl.. Built a bunch over the years... May just want to throw a Edelbrock for a spread bore on it, and call it a day..
 
just one quick thought.. I had the QJ on my 350 mag on my BR back in the day.. swapped it out for a aluminum intake and TB fuel injection unit.. had to replum a couple of fuel lines but the WOW factor was huge !! picked up 3 MPH on the boat.
 
chumbley said:
Sorry - just saw your note on the issues.

Long cold start - could be choke - or could be the fuel bowl leaking down causing the fuel pump to have to fill the bowl first.

Pop on acceration - I would look at ignition related items first.

Accelerator pump failure generally leads to a bog or hesitation on acceleration, not a popping.

Did you measure the pump pressure with a fuel pressure guage?
Click to expand...

The original issue was the bad bog when putting the stick down...you could get maybe 3k and it would fall on its face.It ended up being the fuel filter in the carb inlet.Clogged badly.

Now she seems to run ok except for the long starts when cold or sitting.It defintely feels as if runs out of fuel to start.Crank crank crank.


All new plugs/cap/rotor/wires etc etc with OEM merc stuff.The fuel pressure was on the money with a snap-on gauge.

Like I said, we had some problems after putting the engine in it.We chased a cooling problem for weeks.It turned out to be a clogged transom hose.I put a thru-hull on her and she runs cool.....at the same time we found the clogged inlet filter for the carb.Did both those and took her out for the day and she got up and ran....still have a long start after it sits for a long while during the day.

I just figure it's time for a carb rebuild for a good solid base.
 
shore said:
The original issue was the bad bog when putting the stick down...you could get maybe 3k and it would fall on its face.It ended up being the fuel filter in the carb inlet.Clogged badly.

Now she seems to run ok except for the long starts when cold or sitting.It defintely feels as if runs out of fuel to start.Crank crank crank.


All new plugs/cap/rotor/wires etc etc with OEM merc stuff.The fuel pressure was on the money with a snap-on gauge.

Like I said, we had some problems after putting the engine in it.We chased a cooling problem for weeks.It turned out to be a clogged transom hose.I put a thru-hull on her and she runs cool.....at the same time we found the clogged inlet filter for the carb.Did both those and took her out for the day and she got up and ran....still have a long start after it sits for a long while during the day.

I just figure it's time for a carb rebuild for a good solid base.
Click to expand...

Check fuel pump output/volume, also pull oil dipstick and smell it for fuel contamination...
 
The first thing I would do would be to check that there is fuel in the carburetor after the boat has set for along time and the engine is cold. Without first trying to turn the engine over with the key, manually pull the throttle lever on the carb and see if the accelerator pump squirts fuel. Do this a few times. If the fuel bowl is still full of fuel, it should pump fuel each time. If it only squirts one time then goes dry, it means that the carburetor fuel bowl is leaking fuel while it sits. And therefore it takes the fuel pump 15 secs or so to fill the fuel bowl back up when first trying to start. This process will flood the engine so I would wait 15 minutes or before trying to key start the engine. If the carb is leaking fuel, it makes hot starts hard also because the engine becomes flooded if you turn it off when hot then wait say 5 minutes to start again. You can also look down the carb after it is hot and the motor is off and see if gas is dripping into the intake. Just a thought.
 
I did mine last year because the boat was new to me and I wanted to eliminate carb issues before I even started. I've probably only done 10 or so in my time, as FI was the norm by the time I was in a dealer. Very easy carb to rebuild and reliable as far as I'm concerned. Here's a pretty good guide with pics that will give you the basic ideas of what your looking at. This is for auto, so some things are different. As I said a good guide to see the insides before you decide what to do. I agree with the others that a dunk tank is needed. Here's the link
 
I'm after eliminating any type of carb issue.

I've never dipped into auto carbs but have done many a streetbike carb 4 at a time.

I did find the youtube vids on rebuilding one.There is a link on ********.
 
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