Quadrajet Secondaries Problem

[LuvBoating]

Have a 20ft 1992 Celebrity Cuddy Cabin w/5.7L I/O. Took it into marine service that has "winterized" and "summerized" (northern Colorado) it since Oct 2019. Boat was bought in Jacksonville, FL in 2009.
While in Jacksonville, had the carburetor rebuilt and later, replaced (remanufactured one).

In 2021, engine started loosing power when going on plane. Marine mechanic changed spark plugs, it started great (for not being EFI) and ran great on plane at WOT/4500 rpm's for the mechanic. The marine service has a lake by them. We took the boat to our local lake, started fast again and got up on plane at 28mph. We didn't try WOT, because 28mph is plenty fast for us at mid 70's age.

We were only able to take the boat out once last year, right before boating season ended. Launched it, but couldn't get it fully started. Took to marine service and he told us that, after adjusting the carb, he got it to start and idle. However, he also told us that we'd either need the carb rebuilt or a new one. He then "winterized" it.

So, the boat sat from later October until three weeks ago when we took it in for "summerizing". Mechanic called us and told us that the boat started, but wouldn't idle. Suggested new spark plug wires, rotor and distributor cap (and possibly new spark plugs). After that was done, it still wouldn't idle, so he told us "either carb rebuild or new one". We decided to buy a new one, from the same place we bought the remanufactured one. It's a new Quadrajet,, 5.7L, Electric Choke and Mercruiser Linkage.

Installed today and put on their lake. He called us this afternoon and told us that the secondaries on the carb weren't opening up and carb would start to flood at WOT. He asked me if we told the place we bought the new carb from if we told them what altitude we were at (4,982) and we told him "no". He said "That could be the problem. The carburetor might be for a lot less elevation". I told him that I would call the place tomorrow and tell them about the secondaries problem.

Thoughts?

 

[LuvBoating]

Any ideas of why the carburetor secondaries aren't kicking in? Elevation were at, malfunction in this new (not remanufactured) carburetor or something else, like too old of gas?
BTW, the boat will be headed for storage in Boulder City, Nevada soon and will be put on Lake Mead.

 

[Bondo]

Ayuh,.... Carb tuning does change with elevation, so it might be a small part of yer problem,......
I believe a larger part is you need a Mechanic, rather than a parts swapper,....
I really doubt it's "flooding out" at Wot,.....
The 2ndaries are vacuum, so don't really react unless under load,.....

 

[Lou C]

For one let’s keep in mind that there have not been any truly new Quadrajet carbs since 1990, anything after that is remanufactured if you’re buying it from someone else and that can be a crap shoot. Good, bad, anything in between. So there’s that. I have an original QJet that I’ve rebuilt a few times with better quality parts & it’s been fine. But I’m at sea level no changes in jetting. At altitude this may be necessary due to lowered air density. A carb jetted for sea level may well be too rich at altitude.
On the QJet the secondary system had mechanically opened throttle blades but vacuum operated air doors above them. The opening rate is controlled by an adjustable spring that is a well known adjustment on the QJet.
You need a QJet expert who knows what they are doing or change to a new Edelbrock 1409.

 

[tpenfield]

One thought that comes to mind is that you did not run the boat much last year. So, assuming there is older fuel in the boat, and perhaps it sat in the carburetor untreated over the winter? You would need to know exactly what was done during the winterization to determine this.

Before giving the boat another blast from the 'parts cannon', I'd 'dope' up the fuel with an excessive amount of fuel system cleaner and run the snot out of the engine.

 

[Lou C]

If you want to stick with a QJet go over to Cliffs High Performance Quaradjets, join the forum & start asking questions.

 

[LuvBoating]

Ayuh,.... Carb tuning does change with elevation, so it might be a small part of yer problem,......
I believe a larger part is you need a Mechanic, rather than a parts swapper,....
I really doubt it's "flooding out" at Wot,.....
The 2ndaries are vacuum, so don't really react unless under load,.....

The mechanic who installed the Quadrajet is the same one that has worked on our boat (summerizing/winterizing) and other things, since we moved here in August 2019. Unfortunately, he doesn't know that much about Quadrajets.
And, this marine service is the only one that will work on older boats. If any others, they are miles away from where we live.
I know very little about marine engines, let alone carburetors. So, wife and I have to trust what he is telling us. IOW, I'm a 74 year old "computer geek/user", not a marine mechanic!

 

[LuvBoating]

If you want to stick with a QJet go over to Cliffs High Performance Quaradjets, join the forum & start asking questions.

Just checked that forum out, but didn't see anything about marine QJet! Vehicles, yes, but not marine.

 

[Lou C]

Join the forum and post your question saying it is for a marine application and what your altitude is. Someone (likely Cliff himself) will respond, he does do marine carbs.
Either that, or get a new Edelbrock since Mercruisers were rigged with the very similar Weber carb so you'd be able to get the parts for the accel linkage etc easily.

 

[nola mike]

Or find a hot rod shop in your area. Don't need to be a marine mechanic to rebuild a qjet.

 

[jimmbo]

While the Secondaries on the Q-jet are Mechanical, they are connected to the Throttle thru a spring loaded Linkage. That is because there is a Lock-out that will lock the Secondaries closed when the Choke is not fully open. It is possible that that is why there is no Secondary action

 

[Lou C]

There is also a vacuum operated valve connected to a linkage that has to be sucked in by engine vacuum (like a choke vacuum break) for it to work. When they work, you will know it, we call that the Quadrajet Howl.

 

[LuvBoating]

Or find a hot rod shop in your area. Don't need to be a marine mechanic to rebuild a qjet.

It's a new QJet, not a rebuilt or remanufactured one. New.

 

[LuvBoating]

Contacted a National Carburetors Salesman/Rep this AM concerning the QJet. Wife and I didn't really understand what he was telling us, but he did say something about a spring adjustment. He told us to have the mechanic contact him/them.
At noon, was able to talk to the mechanic on the phone. Gave him the phone number of National Carburetors and he said he will call and get more information about the carburetor.
Just hope this mechanic gets enough information that he can find the spring and adjust it.

Wife and I also remember being told, in 2020, that the old carburetor possibly needed re-jetting since it had come from about sea level (Jacksonville, Florida) to here (about 5,000 feet elevation). But, the one, and only one, marine service that works on old/older boats, doesn't do re-jetting.

 

[nola mike]

It's a new QJet, not a rebuilt or remanufactured one. New.

You sure about that?

 

[Lou C]

It's a new QJet, not a rebuilt or remanufactured one. New.

Made by who? Rochester quit making them in 1990. Mercruiser switched to the Weber 4bbl (similar to the old Carter 4bbl and Edelbrock) and OMC/Volvo went to Holley.
Edelbrock did make Qjets in the '90s but none were marine units. So anybody who sold you a 'new' Qjet, either lied or sold you a chinese copy but it ain't a Rochester QJet.

 

[Scott Danforth]

New Q-jets haven't existed for 24 years

 

[LuvBoating]

Just learned, online, that there are still Q-Jets, in original packaging. Apparently it is no longer being made, but there are both new and rebuilt ones on the market. I just checked Amazon and they sell new ones.

Anyway, it does state on their website, "NEW" for the Q-Jet we bought and that word "NEW" is also on the packing list that came with it from UPS. Now, if it's not new, isn't the company taking a chance of being sued for false advertising?
The Q-Jet we bought from them in June 2016 was stated as "rebuilt" and we paid $199 for it. This "new" cost us $349. Now, I have no idea where they got a "new" one from, but from both their website and paperwork sent with the Q-Jet, it is new.
In fact, the marine mechanic told us he has a new Q-Jet in the shop, but it would cost us some $900, so we said we buy our own.

 

[LuvBoating]

New Q-jets haven't existed for 24 years

I asked the Internet, "are their still new Quadrajet carburetors still available?" and here is the answer I got:
Yes

• According to 4 sources

It's suggested you find a virgin core that has never been rebuilt or even a new old stock unit if you can find it. There are still Quadrajets in their factory packaging out there. Check eBay, Craigslist and Racing Junk websites for options.

 

[Scott Danforth]

I asked the Internet, "are their still new Quadrajet carburetors still available?" and here is the answer I got:
Yes

• According to 4 sources

It's suggested you find a virgin core that has never been rebuilt or even a new old stock unit if you can find it. There are still Quadrajets in their factory packaging out there. Check eBay, Craigslist and Racing Junk websites for options.

And I am a French model

Bonjour