120 Force Flooding - again

jburdadams

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May 27, 2013
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Once again, i know where to come for answers, so i appreciate in advance any help you can provide.
Background: 1999 Mercury Force 120hp
Ran fine day before yesterday. Made the mistake i think, of squeezing the bulb yesterday, and ended up flooding it. I tilted the motor, drained the top carb bowl, disconnected the fuel line and was able to get it running, until I plugged the fuel line back in - flooded and wouldn't restart. Next day, I replaced the inlet needles on both carbs, made sure they were clean, and not sticking, floats are fine and all connections are tight, etc. now it doesn't even 'fire' and is still flooding. thanks
 

Jiggz

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Oct 23, 2009
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3,909
When you said, "Flooding" do you mean fuel mix is dripping out of the carbs's throat? Or is it fuel coming out of the carb's vent holes (located on the side of the carb)? If it is coming out of the carb's throat, with the engine off, can you look inside with a flashlight to see if it is coming of the main jets or even the idle jet while squeezing the primer bulb? If it is then it could be a float adjustment issue and at the same time the carb vent holes maybe clogged or plugged. If it is not, then maybe you are not having a "flooding" but instead have broken reeds and fuel is being blown back out of the carbs.
 

jburdadams

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May 27, 2013
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thanks - i adjusted the tabs on the floats and that seemed to fix the problem, however, now i have a fuel contamination problem. it will idle now for about 30 - 45 seconds then choke down. - fuel mixture is milky - installed new plugs, 2 of the 4 were fouled. going to try the small tank with fresh gas and clear the engine out, then some fuel additive to treat the water in the tank problem. other suggestions? thanks again for the help.
 

Jiggz

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Oct 23, 2009
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I highly suggest you pump out the contaminated fuel from the in-tank as much as you can using a manual pump. Thereafter fill it in with smaller amount of gas, i.e 5 gals at a time, install a water separator filter and ran the boat until you burn all the gas in the in-tank. Make sure you bring in a spare external tank to make sure you make it back to shore. Monitor the water separator, as soon as it starts to show clear fuel, meaning it doesn't catch water anymore then you can start filling the in-tank to its capacity.
 

jburdadams

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May 27, 2013
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Update: i confirmed the fuel contamination in the main tank. It now idles fine on small tank of new gas, but chokes down when i push the throttle forward, so sounds like a different problem now - any ideas?
I still have to treat the main tank contamination problem though - can you recommend a manual pump or method to drain the tank? I'll also be installing a water seperator. Thanks again.
 

foodfisher

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Feb 18, 2009
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3,756
Idle screw adjustment . A stutter/gallop/lag then go usually means too rich. A cough/pop then go =too lean. find the happy middle.
 
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jburdadams

Seaman Apprentice
Joined
May 27, 2013
Messages
41
Update: running fine now. Drained the fuel tank, then ran clean gas from a small tank. Looks like Ethanol is the culprit. will install water separator next, and do a better job of winterizing this year. thanks everyone!
 

Jiggz

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Oct 23, 2009
Messages
3,909
Thank you for coming back and posting the resolution to you problem. It will be very beneficial to others.
 
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