Starts, runs increasing high RPM, and doesn't start again

[ukrsindicat]

Good morning Laddies and Gents,

I have recently swap out my fuel system. I have added a Racor, new inline, changed the lines, cleaned sediment bowl and rebuilt the carb.

Engine started. However, it was running increasingly high RPMs. So I cut it off to adjust the idle needle on carb. It was at about 3 turns. At this point engine shut down and didn't start for the whole day no matter what was the adjustment of needle(1-3 turns from dead screwed in) or openness of choke.

Couple days later I went back to the boat. I opened the the throttle completely and opened choke. Engine started right up once again at the increasing RPMs, but it shut down when I tried to reduce the throttle. Once again I couldn't start it for the rest of the day.

Symptoms:
1. I removed flame arrestor, and found plenty fuel in the throttle.
2. Pulled spark plugs. They are wet with fuel.

So for now, I am suspecting the fuel flooded engine. I know Moyer manual saying that it is "impossible to flood Atomic 4 due to its design". Well, I am all out of options.

I would appreciate you input on this.

[romantic comedy]

It sounds like you may have an air leak.

Did you replace the carburetor gasket? The manifold gasket? Do the carb halves fit correctly, with no gap?

[ukrsindicat]

I replaced the carb gasket, I replaced the sediment bowl gasket. Minifold gasket is replaced. Carb is assembled correctly.

Once again - FUEL IS IN THE CARB AND ENGINE. Like I said the fuel is in the choke when I unscrewed the flame arrestor. I also found spark plugs wet with fuel.

I figure that the air leak would have caused minimum amount of fuel getting to the engine and carb. That is no the case. Engine start up once the excess fuel evaporates.

[ndutton]

There are a couple of indications you're getting way too much fuel and as you said, it's contrary to a vacuum leak that would lean out the mix. Of course, pooling fuel and wet plugs are obvious but also, your report of the engine running with the idle adjustment screw 3 turns out. That's twice as much as normal. At that setting you're trying to get as much air as possible into the mix to compensate for excessive fuel.

I know you said the carburetor is rebuilt and assembled correctly but bruddah, something's not right. Take a hard look at the carburetor float setting, the function of the float valve and be sure there's no sound of liquid sloshing inside the floats.

[ukrsindicat]

I know you said the carburetor is rebuilt and assembled correctly but bruddah, something's not right. Take a hard look at the carburetor float setting, the function of the float valve and be sure there's no sound of liquid sloshing inside the floats.[/QUOTE]
I put the float in the glass of water then put another glass on top, forcing a float to the bottom. Held it there for 30 min and then checked for liquid. None. When I put carb together, I flipped it upside down and tested the float valve sucking the air out and putting a tongue to the hold to make sure it is holding a vacuum...

[ndutton]

A vacuum test on the float valve is the opposite gradient under which it has to work. Try blowing air in with a short section of hose attached to the inlet. It should hold against around 10 PSI (carb inverted).

What about float level? With the carb apart the floats should sit horizontal with the carb inverted.

[Dave Neptune]

IIMHO possibly

uk, did you re-restarting at 1/2 turn off the seat. Anything over 1 1/2 turns out is way to lean if things are OK in the idle circuit.
Did you take a ;look at the plugs? Wet, dry, sooty or wet with gas?

Dave Neptune

[ukrsindicat]

uk, did you re-restarting at 1/2 turn off the seat. Anything over 1 1/2 turns out is way to lean if things are OK in the idle circuit.
Did you take a ;look at the plugs? Wet, dry, sooty or wet with gas?

Dave Neptune

I tried to start with 1.5 turn as well(but that was with gas flooded engine). I should try this with the dry engine.

Ndutton,
When i put the carb together float was sitting horizontal if inverted.

[ukrsindicat]

uk, did you re-restarting at 1/2 turn off the seat. Anything over 1 1/2 turns out is way to lean if things are OK in the idle circuit.
Did you take a ;look at the plugs? Wet, dry, sooty or wet with gas?

Dave Neptune

Spark plugs were wet with gas. There was also gas in the choke opening.

[Dave Neptune]

In the bowl

uk, sounds like the floats and/or a malfunctioning needle&seat. The floats are a critical adjustment and it takes little KRAP to foul the N&S.

Dave Neptune

[ukrsindicat]

Ok, I will take it aparts again and re-check everything. Is there a good thread on this process?

THank you for your help, guys

[roadnsky]

...Is there a good thread on this process?

Maybe consider the CARB Video Clip download?

http://www.moyermarine.com/cgi-bin/shopper.cgi?search=action&category=CLIP&keywords=all&template=Templates/B000_storebuilder.html

[edwardc]

The "upside down blow on the fuel line" test is not a valid test of the floats. This is because while upside down, the closing force is generated by the weight of the floats, while in normal operation the closing force is generated by the buoyancy of the floats. A partially flooded float body will still pass the "upside down" test, but will fail to hold back the fuel pump's pressure, resulting in gas dripping out of the carb! (DAMHIKT)

(Posted while at anchor at Sandy Point off the Great Wicomico. Life is good!)

[sastanley]

(Posted while at anchor at Sandy Point off the Great Wicomico. Life is good!)

Ed, exactly...aren't you on vacation this week? Thanks for the e-mail update..I was a little worried about you guys with the storms today, as the mouth of the Potomac can be trouble sometimes...glad you were safely anchored and the weather was cooperative.

Safe travels!

[ndutton]

The "upside down blow on the fuel line" test is not a valid test of the floats.

Agree but the weight of the float will certainly be less than the buoyancy and therefore the force on the valve will be less so if it holds against air when disassembled and inverted it should only get better in real use. The reason for the suggestion was only to determine if something was holding the valve open.