1989 mercruiser 5.7 carb exchange

[ltfella]

I have a 1989 mercruiser 5.7 with carb 17080561. I see a carb 17082403 for a crusader. Is there a difference inside for tuning or will that not work at all on my engine and find another same number it get theirs rebuilt. To rebuild is more than a new one from that crusader

 

[Bondo]

Ayuh,..... 2bbl. or 4 bbl. carb,..??

If a 4bbl. it should be the standard marine Rochester quadra-jet,....

 

[dubs283]

Should work if it's a quadrajet. Best to check size of the jets and make sure the choke operation is the same

 

[ltfella]

Ayuh,..... 2bbl. or 4 bbl. carb,..??

If a 4bbl. it should be the standard marine Rochester quadra-jet,....

It’s 4 bbl. The crusader is brand new. I decided both says mine is California only and the crusader one isn’t it’s federal emissions

 

[Lou C]

Make sure that it’s actually a marine carb. One difference you can see easily is the barb on the carb body for the mechanical fuel pump overflow hose. Right front part of the carb bowl. Auto carbs don’t have those. I don’t recall seeing any emissions certification on Marine QJets so if I saw that on one I might be suspicious that it was an auto carb not marine. In this pic notice the yellow hose, that goes to the barb....auto carbs don't have that.

 

[dubs283]

Good point, Lou. Would like to think a crusader has a marine carb but who knows?

It's not a "new" carb either. Crusader hasn't made a carbed engine for some time. Either its a new replacement/rebuilt or reman oem

 

[Lou C]

I'm sure that Crusader used a Marine Q-Jet as OEM, but after all those years (they stopped building Q-Jets in about 1990 or so) and people's reluctance to properly rebuild an original (which I don't understand, they are just not that hard to do, at all) who knows what happened!
The only new Quadrajets after that were made by Edelbrock but that was only for a few years and they were not marine units, auto only.
It is a shame really that no one kept the molds etc for the Q-Jet as I feel it is superior to both the Edelbrock (really a slightly updated Carter) and the Holley.

 

[dubs283]

It is a shame really that no one kept the molds etc for the Q-Jet as I feel it is superior to both the Edelbrock (really a slightly updated Carter) and the Holley.

This.

Can't say hiw many times I've seen a q jet thrown in the trash and it breaks my heart. Yeah, they are a bit long winded to rebuild but when tuned property they shine

BTW, Holley does make a fantastic carburetor

 

[ltfella]

Ok here is a pic for the crusader carb. Yes it is a NOS carb. On the bottom right is a vacuum hook up and mine doesn’t have that. Does anyone know where I can hook that up or just plug it..

 

[ltfella]

Ok here is a pic for the crusader carb. Yes it is a NOS carb. On the bottom right is a vacuum hook up and mine doesn’t have that. Does anyone know where I can hook that up or just plug it..

Or would that be something that is not compatable with mine since I don’t have that vacuum hookup.

 

[Scott Danforth]

Automotive carbs have vac ports, marine carbs do not

 

[dubs283]

Automotive carbs have vac ports

Do Pontiac engines also have this feature? And humans who own them also disregard science and known variables about how carbureted engines work?

Asking for a friend......

 

[FORREST3]

Do Pontiac engines also have this feature? And humans who own them also disregard science and known variables about how carbureted engines work?

Asking for a friend......

You have to be kidding? Posting for a friend.. Yea auto carbs (Pontiac,chevy,olds etc..) are different..but very similar in operation..check out the science! I've run a Quadrajet

7029223​

(adjusted/slightly modified) and set-up for marine use) on a (5.7) 350 c.i. boat..it worked great!. but not "correct".Castings are very similar..mercruiser contracted with quadrajet for their marine applications..