Johnson 5.5 carb issue

[archangel]

This would seem like a relatively simple issue, but my ignorance has me stumped. 😳

I have just gone through the standard, carb rebuild, new fuel lines, new impeller and all the gaskets, and a complete coils, condensers, points replacement on a 1960 Johnson 5.5 bought that wasn’t running when I got it. The issue now is that I can fire it up on the first pull, but the carb seems to be flooding it out after about 2 seconds of running, and when it stalls it spits a big gulp of fuel from the air horn. I have had the carb back off twice now and taken it apart again and again to make certain all the passages are clean, no parts were overlooked in the rebuild, and that the float sits level. Does anyone have any advice for my next steps?

EDIT: I overlooked including my replacement of the fuel pump with a complete NOS unit I bought. The fuel line from the tank is a brand new OEM BRP piece, too. The needle setting I have currently set are: 1 turn from seated on the high speed; 1.5 turns from seated on the low speed.

[chris-p]

I like to set the float, so that the unhinged end, is slightly higher than the hinged end. This ensures it seats the needle when the bowl fills.

Perhaps debris in the seat? Open up the needle and try to flush it out while running.

[archangel]

Thanks, Chris. With respect to setting the float with the hinged end slightly higher, you mean with the carb upside down, correct?

EDIT: Sorry, confused myself trying to be clear. That would be lower on the unhinged side when upside down so the float lifts higher when right-side up, correct?

[archangel]

I’ve tried those fixes now and I still have the same outcome; it will start on the first pull, run for a second or two, stop and belch fuel from the air horn.

[Mumbles]

It might be leaking around the brass float valve, especially if it isn’t tight enough or the plastic sealing washer is missing. The correct float valve is 396522 and it can be purchased separately from your friendly OMC/BRP dealer.

[archangel]

That is the precise BRP kit I used. I had installed the plastic ring in the rebuild and the float valve seems tight.

EDIT: The needle spring is installed and the needle seat is nice and clean, too.

[Mumbles]

Although it doesn’t seem to make any difference, the 439071 carb kit comes with a 396521 (765555) float valve while the diagrams at Marine Engine call for a 396522 (765561) float valve for this carb. I’m not sure what the differences are.

http://www.marineengine.com/parts/johns … etor+Group

On one carb I had which leaked like yours, the seat was too long and bottomed out on the carb body causing a major leak. It took two or three sealing washers and some serious adjusting of the float to get it working right until it could be replaced with a correct part. Just something to consider.

[fleetwin]

Are you sure the carb is flooding? You mention that it starts and runs for a few seconds, then dies and spits a little fuel out of the carb. Does the carb leak when you just pump up the fuel and make no attempt to start it? Does it continue to leak after it stalls? Maybe you have a stuck reed causing the stalling and fuel spitting back. Please don’t go ripping into the intake manifold on my guess, but I just want you to make sure the carb is actually flooding over.
You mention a new fuel pump, just because it is new doesn’t mean it is any good, perhaps its diaphragm is leaking filling up one crankcase with fuel.
Again, PLEASE don’t rip that fuel pump apart based on my wild guess.
In any event, it might be easier to leave the carb off the manifold with the fuel line connected, then pump up the fuel (while holding the carb in its normal position to confirm that the carb is leaking. This might save a little time and make it easier to pinpoint why the carb is leaking, if it is indeed leaking.

[chris-p]

^^^Fleetwin makes very good points here.

When you prime the carb, does the bulb get firm, without fuel leaking from the carb?

I wonder if something as stated above, is killing the motor, and the leaking fuel is a side effect of that?

What are the needles set at?

[archangel]

I have the high speed set at 1 turn from seated and the low speed at 1.5 from seated.

Actually, the carb does belch fuel when I pump the primer bulb. At the risk of sounding really dim-witted, I tried turning the float over in one of the iterations I have tried since this morning and the carb doesn’t belch fuel when the primer bulb is squeezed with the float that way and the motor starts and clearly runs out of fuel in that configuration. What does the fuel coming from the carb air horn when the primer is squeezed suggest to you?

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