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]

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]

Originally Posted by Dave Neptune

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]

Originally Posted by Dave Neptune

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]

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]

Originally Posted by ukrsindicat

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

Maybe consider the CARB Video Clip download?


http://www.moyermarine.com/cgi-bin/s...rebuilder.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]

Originally Posted by edwardc

(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]

Originally Posted by edwardc

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.

[ukrsindicat]

Gents, thank you for suggestions.

I do have a question.
Shouldn't starter fluid sprayed into the throttle change anything?
I thought that starter fluid is a way to troubleshoot and exclude carb out of the problem. I took the flame arrestor off and sprayed the starter fluid inside the chock shutter. However, engine still wouldn't start...

[JOHN COOKSON]

It sounds to me like you are running rich and have an ignition problem.
The next time the engine doesn't start pull the center wire out of the distributor and hold it close to the engine and crank the engine ane check for spark. We'll go from there.

TRUE GRIT

[Mo]

Originally Posted by JOHN COOKSON

It sounds to me like you are running rich and have an ignition problem.
The next time the engine doesn't start pull the center wire out of the distributor and hold it close to the engine and crank the engine ane check for spark. We'll go from there.

TRUE GRIT

I tend to lean toward John's thinking....perhaps you have a couple of issues.

[ukrsindicat]

So any of you gents have have suggestions on how do I troubleshoot my carb? I have assembled it with rebuild kit. How do I regulate the float? How do I set this up? I did an upside down float test, and carb held the vacuum(see above).

[romantic comedy]

I would install the carb, and run the engine.

[ukrsindicat]

Its already installed. I rebuilt it with all new float valve, gaskets, springs, idle needle, etc. Now I need to find out what did I do wrong in the carb itself. According to above opinions, the general thought is that I have incorrect float adjustment which floods the carb (although I have not changed it since I took carb aparts when it WAS working).
So now I need to verify proper float valve/float adjustment. How do I do this?

Thank you guys

[romantic comedy]

You can bench test the float. ALso did you replace the needle valve. If that is not seating, the bowl will overflow.

Put the carb on the bench, and hook up gas to an overhead gravity feed. It will fill the bowl. This makes it easier to trouble shoot.

If you think the float is not adjusted correctly, bend it so it works. That is all you can do.

You can do the same thing on the boat, with the gravity tank. This bypasses the fuel pump, in case there is too much pressure.

[ukrsindicat]

Originally Posted by romantic comedy

You can bench test the float. ALso did you replace the needle valve. If that is not seating, the bowl will overflow.

Put the carb on the bench, and hook up gas to an overhead gravity feed. It will fill the bowl. This makes it easier to trouble shoot.

If you think the float is not adjusted correctly, bend it so it works. That is all you can do.

You can do the same thing on the boat, with the gravity tank. This bypasses the fuel pump, in case there is too much pressure.

I did replace the needle. I screwed it all the way in, then back it out 1.5 turn.

How do I know bowl is operating correctly. Some gents in above posting suggested that my bowl adjustment is off. I am not sure how to determine that it is correct.

[Carl-T705]

Don't confuse the idle needle valve with the float needle valve. It only takes the slightest particle of dust to prevent the needle from closing on the seat to cut off the flow of fuel. remove the bowl and blowout the float needle valve, spin the needle around on the seat to remove any oxidation that may be there. Be sure your spark plug gap is set to specs., some folks think a larger plug gap makes for a hotter spark, what it makes is greater difficulty in producing a spark and premature ignition failure. I've learned years ago working around engines "NEW doesn't always mean GOOD and GOOD doesn't always mean NEW"!! Good Luck.

[ukrsindicat]

Originally Posted by Carl-T705

Don't confuse the idle needle valve with the float needle valve. It only takes the slightest particle of dust to prevent the needle from closing on the seat to cut off the flow of fuel. remove the bowl and blowout the float needle valve, spin the needle around on the seat to remove any oxidation that may be there. Be sure your spark plug gap is set to specs., some folks think a larger plug gap makes for a hotter spark, what it makes is greater difficulty in producing a spark and premature ignition failure. I've learned years ago working around engines "NEW doesn't always mean GOOD and GOOD doesn't always mean NEW"!! Good Luck.

Great! I will give it a try. I have changed both idle needle and float needle valve