3.0 mercruiser ran for 5 min good. Then Just died?

ilove2fixx

Chief Petty Officer
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Feb 13, 2016
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501
well it ran for couple min then died , without me touching anything this time! 😂 but carb has fuel not like last time. it seems like it gets flooded as it wont start easily again. i have to turn back the idle mixture to start her. this boat is giving me more grey hair 😂🥴🥴
 

CaptnKingfisher

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May 14, 2017
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well it ran for couple min then died , without me touching anything this time! 😂 but carb has fuel not like last time. it seems like it gets flooded as it wont start easily again. i have to turn back the idle mixture to start her. this boat is giving me more grey hair 😂🥴🥴
Do you know what your doing when you say you are setting the idle mixture screw? Like are you confident you have it adjusted correctly or do you want instructions?
 

ilove2fixx

Chief Petty Officer
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Feb 13, 2016
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u know guys i forgot to mention i always smell gas when im.next to the boat. with my previous boat i didnt. Maybe i might have a loose hose or hole in the tank ? or maybe from all that cranking just lots of fuel in the intake /carb ? gas will stay in the carb for days right? normal when u take off the tarp or cover to smell gas ?
 

j cat

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Oct 13, 2015
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u know guys i forgot to mention i always smell gas when im.next to the boat. with my previous boat i didnt. Maybe i might have a loose hose or hole in the tank ? or maybe from all that cranking just lots of fuel in the intake /carb ? gas will stay in the carb for days right? normal when u take off the tarp or cover to smell gas ?
well I smell gas on the outside around the boat when the air temp rises . now my wellcraft has the gasoline vent on the driver side on the outside of the windshield area...next to the fill port.....
my 1996 Impala last year smell gas around it .. then the gas tank vent rubber hose was cracked .. fix it ... cars have a charcoal canister to suck up the gasoline vapors..
if you smell gas vapor around the engine or smell around the tank area could be a leak ...I had to change the gas line on my boat , from the gas tank to the fuel pump a few years ago....rubber hose had cracks on it so no leaks and then I changed it ...
 

ilove2fixx

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Feb 13, 2016
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ok i got her to run again. only to die after couple min of running ?? 🤷‍♂️🤷‍♂️ i can get her to run again but rough and just over all same stuff again and again.. i Noticed couple times after she dies , i manually pump fuel with rocker arm ( i took off the throttle cable ) and no fuel ? But i hit the side of the carb and i hear like pressure release, and then it would start again. im thinking the damn float needle sticking.
 
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ilove2fixx

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Feb 13, 2016
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i also want to check the fuel tank and pick up line but how to remove this ? I cant even fit a wrench or my hand in there.

20220410_184129.jpg
 

Scott06

Admiral
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Apr 20, 2014
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ok i got her to run again. only to die after couple min of running ?? 🤷‍♂️🤷‍♂️ i can get her to run again but rough and just over all same stuff again and again.. i Noticed couple times after she dies , i manually pump fuel with rocker arm ( i took off the throttle cable ) and no fuel ? But i hit the side of the carb and i hear like pressure release, and then it would start again. im thinking the damn float needle sticking.
Yes this would be indicative that needle and seat are hanging up. If you rebuilt the carb with a cheap kit may be worth getting a quality kit.
 

j cat

Petty Officer 2nd Class
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Oct 13, 2015
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i also want to check the fuel tank and pick up line but how to remove this ? I cant even fit a wrench or my hand in there.

View attachment 358641
take out the rubber fuel line .. see if it is cracked ... take the hose out to put a wire on the hose and then pull it out ... then put the new hose in to slie in correctly easy..
 

ilove2fixx

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Feb 13, 2016
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Yes this would be indicative that needle and seat are hanging up. If you rebuilt the carb with a cheap kit may be worth getting a quality kit.
yeah my last boat i bought an oem mercruiser kit didnt have an issue this time i got 2 cheap kits and tons of issues 🥴 ill order a good kit and do it carefully this THIRD time around 😂
 

ilove2fixx

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Feb 13, 2016
Messages
501
Yes this would be indicative that needle and seat are hanging up. If you rebuilt the carb with a cheap kit may be worth getting a quality kit.
yeah my last boat i bought an oem mercruiser kit didnt have an issue this time i got 2 cheap kits and tons of issues 🥴 ill order a good kit and do it carefully this THIRD time around 😂

Yeah, if the fuel is old, it won't burn correctly. I'd get rid of it, flush the tank and add some new premium fuel.
but i got a full tank of it 🥴😑 ive always used fuel that looked like that ? infact the fuel u saw was actually recently bought but was outside for over a week..in that clear bottle u saw.
 

Grub54891

Admiral
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Jun 17, 2012
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6,078
but i got a full tank of it 🥴😑 ive always used fuel that looked like that ? infact the fuel u saw was actually recently bought but was outside for over a week..in that clear bottle u saw.
put some on a dry stick, or on the ground. See if it lights.
 

ilove2fixx

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Feb 13, 2016
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What's the history on the engine? Was it running good for you last season?
i bought it couple months ago and i recall the guy saying he has a hard time starting it. So i rebuilt the carb twice and still have issues. i have tried to do the idle adjustment but she wont go under 900/1000rpms
 

CaptnKingfisher

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May 14, 2017
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i bought it couple months ago and i recall the guy saying he has a hard time starting it. So i rebuilt the carb twice and still have issues. i have tried to do the idle adjustment but she wont go under 900/1000rpms
Are you confident that you have idle mix set correctly? Set idle mix correctly first, then use idle speed screw to lower rpms to spec. If you cannot get rpms low enough you may need to adjust throttle linkage.

I suspect fuel issue like others have said. I would start diagnosing by testing fuel pressure (as was recommended earlier). Then you know if your issue is upstream or downstream of the carb. I would guess if you were to prime the engine several times before each crank, it'll probably start every time but die shortly after. I suspect either carb mix too lean, or pinhole leak in fuel line or vent issue or some other fuel starvation thing going on. Best way to find it is to be methodical.
 

achris

More fish than mountain goat
Joined
May 19, 2004
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27,468
My troubleshooting path with 'unknown' engines and faults is to do a compression test, check spark and timing, and only when I KNOW they are right will I move onto the fuel system. Almost never the first point of attack unless I KNOW it's a fuel system problem.

Chris...
 
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