Marine Carb rebuilds

[randy4140]

Cliff, from what I hear on here and "internet" you are the one with the q jet answers..
How about the marine carbs. I have twin GM 305's in my 29 ft CC Catalina. does have wedge plate under carb to somewhat level them out. No mods to engines, and are straight shaft inboards. 8000lbs. I would think that at around 3000 rpms I should only be on the primaries, and the fuel usage should be not bad with the twins, (that being said I know it is a boat and they like fuel) It seems like I am using a lot of fuel and have rebuilt the carbs, there was considerable debris in the bowls ect. They seem to run fine but am wondering what base settings I should be using for marine use. All your info in the book is pointed at automotive use. Can you help or is there somewhere else I should be looking. Thx in advance.

[Ethan1]

Cliff, from what I hear on here and "internet" you are the one with the q jet answers..
How about the marine carbs. I have twin GM 305's in my 29 ft CC Catalina. does have wedge plate under carb to somewhat level them out. No mods to engines, and are straight shaft inboards. 8000lbs. I would think that at around 3000 rpms I should only be on the primaries, and the fuel usage should be not bad with the twins, (that being said I know it is a boat and they like fuel) It seems like I am using a lot of fuel and have rebuilt the carbs, there was considerable debris in the bowls ect. They seem to run fine but am wondering what base settings I should be using for marine use. All your info in the book is pointed at automotive use. Can you help or is there somewhere else I should be looking. Thx in advance.

 Welcome to CHP!

 What are the carburetor numbers stamped on the Quadrajet's? Should start out 704xxxx, 1705xxxx or 1708xxxx.

[randy4140]

one of them is, 17080564, and below this # is 3174
the circle #s are17060303.
Sorry I should have included that info before in the post

[randy4140]

Cliff, Ethan....Any ideas, on Base marine setting, or necessary adjustments, economy adjustments, Ethan wanted the carb #'s, which I replied
Any help is appreciated
Randy

[Hillbillyenginering]

A few things you should understand about marine engines. The can grind on them are usually more aggressive than autos. The ability to cool the engine is much greater,because of all of the heat transfer to the surrounding water. So when you say "stock" it would probably have higher compression and aggressive cam. Look up the info on them and compare to what even a stock corvette would be.
I bet your stock rebuild would be on par with cliffs recipe #1.
If at all possible source two of the same model numbers.
Buy the rebuilds kits from cliff. Buy the upgraded super sckucuum one!

[Ethan1]

Cliff, Ethan....Any ideas, on Base marine setting, or necessary adjustments, economy adjustments, Ethan wanted the carb #'s, which I replied
Any help is appreciated
Randy

 Sorry, Randy. Been busy with my dog. He just surgery on his foot and now just got infected. So, back on darn antibiotics!

 Anyways, Hillbilly knows what he is talking about and I agree with him 100%. Also, I am not 100% sure, but you may have problems finding a rebuild kit for the 17060303. Not sure if, Cliff, would carry one for that carb number, but wouldn't surprise me if he did.

 Also, what base Marine settings are you looking for? Float height? Float drop? Idle mixture screw adjustment? Etc.?

[randy4140]

Eathan/Hillbilly, Thx for the replies ! I had to get "local" kits quick to get back on the water, but may go over them again in the off season. The kits I got are supposed to be "ethanol approved" for what that may be worth..lol
The pump in the starboard engine was shot, don't know how it ran as well as it did. I did have a needle seat issue with one of the kits as Cliff suggests might happen, so will probly do them again and replace the float at that time. As for settings I was looking for idle mixture float drop ect that might have been more specific to the marine engines. I will try and tune them in best I can and "see how it goes" The more I can keep them off the secondaries, the more I can stay away from the fuel dock...ouch $4.00/gal plus. Eathan sorry about your dog, hope he heals quick !

[Ethan1]

Eathan/Hillbilly, Thx for the replies ! I had to get "local" kits quick to get back on the water, but may go over them again in the off season. The kits I got are supposed to be "ethanol approved" for what that may be worth..lol
The pump in the starboard engine was shot, don't know how it ran as well as it did. I did have a needle seat issue with one of the kits as Cliff suggests might happen, so will probly do them again and replace the float at that time. As for settings I was looking for idle mixture float drop ect that might have been more specific to the marine engines. I will try and tune them in best I can and "see how it goes" The more I can keep them off the secondaries, the more I can stay away from the fuel dock...ouch $4.00/gal plus. Eathan sorry about your dog, hope he heals quick !

 Randy, That is a Holley Reman carb, so if you have questions tuning it to spec, I would give there tech line a call. 866-464-6553

 Also, Baxter is doing well. Had to where the cone of shame for a few days. He sure didn't like it, but it was for his own good. He is a Basset Hound by the way. My buddy and best friend! Take care and hope you get that CC up and running properly.

 If you have anymore questions, feel free to post whatever questions you have! God bless. Ethan

[Ethan1]

 Here is some more info:

 Float Height: 15/64"
 Pump Rod Hole Location: Inner
 Air Valve Spring Wind Up: 3/8" (Turn 60-75 Gr.)
 Idle Mixture Screw Setting: 2-3 Turns Out
 
 HTH!

[randy4140]

Holley Reman??? Now I am confused. It clearly says Rochester Quadrajet?? Whats up?

[Ethan1]

Holley Reman??? Now I am confused. It clearly says Rochester Quadrajet?? Whats up?

 Disregard that post. I couldn't edit it in time. Holley made a similar Qjet, with same carb number. Clearly, yours is not a reman.

[Cliff Ruggles]

I'd go back to basics.  If you rebuilt the carbs and are not getting a good result, and didn't put new floats in them, and most likely the incorrect fuel inlet seats as well, I'd get our complete Marine kits and go back thru them again.

This time install new floats, the correct high flow N/S assemblies, correct length accl pumps with our seal on them, and make sure the floats are set exactly to factory specifications.

We supply instructions for them with the kits.   Also make sure that the power piston hanger arms are level and exactly even.

Do NOT modify the carbs in any way, they are not emission calibrated and set up exactly for those engines.  I would clean out the idle tubes during the rebuild, but don't recommend removing them.  You can straighten out the old accl pump return spring and use it to push thru the idle tubes as a cleaning tool.

Once you have installed the correct parts, and new floats at the right height, I'll be they start working like they are supposed to and fuel consumption will be minimal and back on par for the application.......Cliff