Mercruiser Alpha1 3.0 ltr LX Two Barrel Carburetor Flooding Problem

[sciulli]

Had a flooding problem; gas still drips into carb from the venturis after turning off key. Changed distributor cap, rotor, plugs. I installed a rebuilt carb, new fuel water separator, emptied fuel tank and filled with new gas. Had the same problem, so I sent the carburetor back to be tested and rebuilt again. Still having the same problem. Am I missing something here, some adjustments, etc? 1998 Bayliner Capri 1952 Cuddy Cabin engine #0K155713 carb 807504. Thanks in advance.

 

[Fastatv]

Had a flooding problem; gas still drips into carb from the venturis after turning off key. Changed distributor cap, rotor, plugs. I installed a rebuilt carb, new fuel water separator, emptied fuel tank and filled with new gas. Had the same problem, so I sent the carburetor back to be tested and rebuilt again. Still having the same problem. Am I missing something here, some adjustments, etc? 1998 Bayliner Capri 1952 Cuddy Cabin engine #0K155713 carb 807504. Thanks in advance.

Could be several things:
1. Check float height, I know you said it was rebuilt but, re builders don't always get it right.
2. Is the power valve actuator mating with the power piston,
3. Whats your idle speed,
4. Have you adjusted the a/f mixture screw?
Item one and two require some carb dis-assembly of course.

 

[woody66912]

Make sure they replaced the gasket under the venturis block.

 

[sciulli]

see below

 

[sciulli]

see below

 

[sciulli]

I believe the gasket under the venture block has been replaced. How would you check it? Can you check it visually? Haven't adjusted the A/F mixture screw because once I do get it started it runs great and idles at 800rpm. I'm not to great in checking the float level. That's why I sent it off to have it rebuilt twice, hoping they will get it right. The original carburetor did the same thing, just seems strange that the rebuilt one is doing the exact same thing too.

 

[woody66912]

OK, let's throw this at it, are you in the water "Boat floating" or on land. Seeing how both carbs do the same thing it could be that when floating the boat sits so unlevel that the float when set to spec thinks it's way off. Or are you on land on the muffs with it level?.

 

[sciulli]

On land and level with muffs on. Put rebuilt carb on and it started first time great. Ran it for 15 minutes and then shut it down. Started back up great second time. ran it for 5 min then shut it down. The third time it wouldn't start. took off cover and saw gas trickling in carburetor. Couldn't get it started the rest of day. Took carb off and sent it back to get rebuilt again. put back on and it started great twice on land with muffs on. Took it to water and no luck, third time would not start. Trailered engine and put full throttle and jumped the starter. It started. But after turning it off wouldn't start again at idle and gas was still tricking in carburetor.

 

[sciulli]

Oh... and checked fuel pressure. It was 7 PSI. I did change fuel water separator and there is a new fuel filter in carb. I also and emptied fuel tank and added new gas with a can of sea foam.

 

[woody66912]

Thinking.

 

[woody66912]

When i rebuild carbs, I for the most part i don't use the gauge to set the float. I flip the top carb body upside down a set the float just a little (high) some times if you set the float level it won't hold, I had the auto parts store make me a "short" double flare fuel line with compression nut, then when I'm done i set the carb on the floor and use my shop tank, setting on the bench to test the float setting, Maybe you could have one made and do the same, or bring your setup to the rebuilders and show them that the float is not holding?.

 

[sciulli]

Thanks for the advice. I believe it is the float level too. Just thought i might have missed something.

 

[fishrdan]

Oh... and checked fuel pressure. It was 7 PSI.

Sounds like you found the problem as the fuel pump pressure should be 4-6PSI. 7PSI is pushing past the float's needle and seat and causing the carb to overflow,,, drip.

 

[sciulli]

Should I buy a new fuel pump or is it possible to put a regulator on it?

 

[sciulli]

It is a stock mechanical fuel pump. Can the 1 psi disparity really make a difference and how would the fuel pump all of a sudden pump more PSI? What are my options? Number one send back carb to be rebuilt once again and replace fuel pump?

 

[rcer22]

Hey all.
I'm gonna watch this topic because I have the same problem. I have a 2009 Bayliner with the 3.0 engine and a 2 barrel TKS gen 2 carburetor. I have had it apart several times and I know all the settings are correct. I even changed the float because it weighed a tad too much. I first thought it was the venturi cluster center screw seal because it was loose. I rebuilt the carb and it was fine for several days but the problem has returned. Both barrels collect about 1/2 in. of fuel. I started it up today and after it warmed up it began to run rough and stall. By the time I got the air cover off it had fuel in the barrels. I then suspected the fuel pump is putting out too much pressure. So I asked the owner of the marina about the pump and he said he has never seen a fuel pump fail and put out too much pressure. When they fail they either don't put out enough or don't put out anything at all. It would be nice to just get away with a new fuel pump.LOL I would put in one that does not have that pain in the ass filter in the bottom of it. You know the one with the bail. I'm already using 2 other filters. The one at the carb and a water separating can type that I installed 3 years ago. I'm also thinking that the check ball under the venturi cluster that covers the circuit from the accelerator pump well could be letting fuel pass on an intermittent basis and flooding the carb. There could be a piece of dirt keeping the check ball from closing properly or a weak hold down spring allowing the check ball to open under low vacuum such as would be found above the throttle plates at idle.
I hope you find your problem soon. The summer is winding down here in the Adirondacks of upstate New York.

 

[Bikeluver43]

Is there fuel in the clear line going from the pump to the carb?

 

[sciulli]

No fuel in the clear tube leading from fuel pump. I even removed it and still had fuel tricking in carb.

 

[rcer22]

I believe the fuel that you see trickling is actually fuel just dripping off the upper parts of the carb that were soaked with fuel while the engine was idling and flooding. Now that the engine has stalled you can see the fuel dripping. The only way to tell is to look into the barrels while it's idling and ready to stall and after it stalls see if the fuel was there before it stalls. I Think the fuels floods the barrels while the engine is idling. Then that is what stalls the engine. I thought that same thing when I first looked in the barrels. I removed my carb and pressurized it on the bench with an electric fuel pump. I put a gauge on it and had 4 pounds of pressure and still saw no fuel leaking or trickling. It's something to do with the engine vacuum that draws in fuel to the barrels. Either that or you have very high fuel pump pressure.