NEED HELP!!! mercruiser 140 only starts with WOT then dies at idle??

stillfloating

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Jun 4, 2015
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Hi everyone I'm new to the fourm but a long time reader. i have a 1985 17ft celebrity, with a mercruiser 140 and alpha one outdrive. i bought the boat over winter and went through everything and it seemed to be all good. started the boat for the first time on muffs and is started up second try and ran great. took it to the launch and it idled very rough and then died then would only start with wide open thottle and would die when i went to throttle down. took it home let it sit for the night and it started right up the next day. replaced the impeller and went to test it. did the same thing no start only with WOT and dies when i go to put it in idle. has spark but might be weak? not sure and carb was getting fuel. so i replaced fuel filter put additive in fuel and rebuilt carb. carb looked in pretty good shape but decided to rebuild anyways. and now i still have the same issue. :mad:I'm lost not sure where to start now. :confused: most of this is new to me so any help or advice would be greatly appreciated.
 
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alldodge

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Hi everyone I'm new to the fourm but a long time reader. i have a 1985 17ft celebrity, with a mercruiser 140 and alpha one outdrive. i bought the boat over winter and went through everything and it seemed to be all good. started the boat for the first time on muffs and is started up second try and ran great. took it to the launch and it idled very rough and then died then would only start with wide open thottle and would die when i went to throttle down. took it home let it sit for the night and it started right up the next day. replaced the impeller and went to test it. did the same thing no start only with WOT and dies when i go to put it in idle. has spark but might be weak? not sure and carb was getting fuel. so i replaced fuel filter put additive in fuel and rebuilt carb. carb looked in pretty good shape but decided to rebuild anyways. and now i still have the same issue. :mad:I'm lost not sure where to start now. :confused: most of this is new to me so any help or advice would be greatly appreciated.

:welcome: to iboats

Sounds like your carb might be flooding your engine. In to top of this section there is DonS adults only section which gets into all kinds of troubleshooting things. Your engine cranks, but won't start unless your carb is WOT position. Sure sounds like the carb is flooding the engine. It starts first thing because the fuel bowl has leaked down and is not flooding. Recheck your float level
 

stillfloating

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Jun 4, 2015
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okay thanks for the info!! i set the float to spec but i had the option to put in a spring loaded needle and seat. i read that that helps with a flooding issue. i stuck with the soild pin because that what was in there originally, should i change that?
 

alldodge

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okay thanks for the info!! i set the float to spec but i had the option to put in a spring loaded needle and seat. i read that that helps with a flooding issue. i stuck with the soild pin because that what was in there originally, should i change that?

I would find out if you have flooding going on first. Need to find out what your issue is, then figure out a path to fix it. When it won't start look down the carb and see if you have fuel spilling down the throat. If there is gas dribbling in then need to check float level and if the float is to heavy and needs replaced which causes the float to sink in the bowl
 
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