Marine Quadrajet Flooding Out

[rozicrc]

I have a marine quadrajet 17083522 that I rebuilt with one of Cliff's kits as the idle circuit was plugged up.  It is on a mercruiser 3.7 liter engine, and the float was set to 3/8".  I had issue with the carb stalling out when the boat was warming up in the water, where the back end sits a little lower than the trailer, and fuel would spill out of the intake gasket to carb mounting surface to the point where I would not start it again for several hours as I was afraid of a fire.  Long story short, I have rechecked the float measurements for appropriate setting at 3/8", vacuum checked the needle and seat assembly, installed a fuel pressure regulator set at 4 psig, and today have had the same issue.  The issues seems to get worse when I park the boat on a steeper incline, in other words if I lift the bow up by parking on a steeper part of my driveway I get more fuel running down the backside of the carb.

I am starting to wonder if I could have a needle/seat leaking by, or if the listed 3/8" is not the correct float setting.  Please help!!

rozicrc@hotmail.com

[StillLearning]

Try dropping the float to 1/2" or so and see if the flooding goes away. There are other reasons for flooding but this is one of the most common.

[Cliff Ruggles]

3/8" is PLENTY low for a Marine unit.  You have other issues someplace.

Could be leaking at the gasket under the seat, float arm bent/dragging, or the clip on the needle is hooked incorrectly into one of the holes on the float arm, but the problem would not be float level......Cliff

[rozicrc]

I actually disassembled the carb and put regulated air on one side of the carb, and filled with water to test for float operation.  The water shuts off the flow of air at 4 psi and 1/2" below the top of the bowl.  At 5.5 psi I get sputtering but increasing the water level or dropping the pressure back down seals it.  The carb is angled down 10 degrees on the boat.  Other than trying the wedge should I try and swap floats?  This is a brass unit at 9.91 grams so it is borderline for the spec of 9.88

[rozicrc]

Oh and no clip on the needle it is gone per the book.

[Cliff Ruggles]

We don't supply, use, or recommend brass floats, especially for Marine units.  It didn't come with any kit you got from us, we don't even have them in stock.....Cliff

[rozicrc]

I think I installed the old float by mistake.  Is the one you supply black plastic with f76 and 1073 on it?  I will change out and see if it resolves.  i know I have your needle and seat as the old ones are 1/8"diameter and I disctinctly recall getting the thick carb mounting gasket from you.  I am not sure why the float makes a difference but I will give it a go THANKS!!!

[rozicrc]

I installed the plastic float today and pitched the brass one.  I did install the wrong
One.  I checked and I have the new needle and seat in the carb already as well.  Good news is the carb flooding is now a thing of the past.  Bad news is the boat won't run for more than 30 seconds.

I get it to start but it chokes out and stalls, easier to do when running rich with a spritz of starting fluid..  I have checked spark, timing, choke opening , moved fuel pressure between 3.5 and 6 psi, verified timing is 6 degrees advanced, and tried 2 to 4 screws open on the idle adjustment screws to no avail.  I also checked fuel filter as well.  Only thing I noted is the fuel left a yellowish residue when I was taking plumbing apart. 

The fuel was stabilized but I am wondering if in the last 14 month if the fuel has weathered the light ends off.  Boat runs for a couple of seconds when I put fresh fuel in thought the primaries.  Is there anything else I should check before plumbing up to a source of fresh fuel?  Are these symptoms consistent with weathered fuel?

[rozicrc]

Also tried float setting of 3/8 and 1/4 and 7/16

[77cruiser]

Is their any fuel in the carb when it dies? Does the accel. pump squirt fuel?

[Cliff Ruggles]

Set the float to the factory specs, this makes sure the right amount of fuel is in the bowl.  We don't troubleshoot fuel delivery problems, or flooding problems by raising/lowering the float.  It needs to be at the correct factory setting by carburetor number for Marine applications......Cliff

[rozicrc]

I'm giving up on this.  I have been messing with this for 11 months on and off and have snow missed a boating season due to it.  I checked the other carb and swapped it to the same plastic float that it is suppose to run.  I have broken this down and leak tested with air.  I just threw away 25 gallons of gas I thought could be bad and still have the engine dying when the carb floods out.  I can't find a leak on the needle/seat nor can I see fuel pressure bounce over 4.5 psi.  If the needle is not bouncing off the seat without a spike in pressure being readable I don't know what this could be.

Cliff if I send this to you to fix could you run on the test engine to se if you have the same symptoms I do before resorting to a rebuild?  I regret chaning the fuel pump at the same time as the carb rebuild as now I can't rule it out, but I am stumped as to how this could happen with the fuel pressure regulator installed as well.

[rozicrc]

Changed the plugs and tried - nothing still died after a few seconds. Changed the coil back to stock and it ran well. Ignitor ii coil went bad with maybe 8 hours on it. I figured it was still flooding out as it would run and die like it did with the bad float/new fuel pump, but it was just what shook into the carb brought the primaries when it would start to run rough and stall. At least I know quadrajet tear downs that o could literally do blindfolded now!

Thanks to all who helped, this was a pain but I am glad we were able to resolve

[Cliff Ruggles]

That's good news. 

Just to let you and everyone else know.  If you get stumped on a carb rebuild, (hopefully you used our parts in it), send it to the shop with a note and we'll take it apart and check everything, then run it on our test engine.

I do this a lot for folks who are having running issues and think it's the carb, but are not entirely certain.  We only charge time/materials for this service, and return shipping....Cliff

[rozicrc]

Thanks again it was helpful.  On a side note the right setting on the float was 7/32 the rebuild kit speced, not the 3/8 the mercruiser manual specified.  It is up and running.