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98 mercruiser 5.7 Carb start no run

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Old 06-09-2019, 08:26 PM
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Exclamation 98 mercruiser 5.7 Carb start no run

Hello have original motor 375 hrs. Unit has been sitting for extend period of time 2 years. Engine starts then dies right away will not idle tried spraying starter fluid still same results. Removed all old gas from tank all so replaced the spark plugs, wires, coil, cap, and rotors. Also replaced the manifolds and risers to if clogged. Checked cylinder compression all were above 100 psi. Rebuilt the carberator when starts see fuel spraying out of the carb. It is in the run position. When cranking have only 11v at coil positive. Thinking batteries not holding the charge or lanyard switch is gone bad.
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Old 06-09-2019, 09:35 PM
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Sounds like you have fuel. Do you have spark?
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Old 06-10-2019, 06:41 AM
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Spark is there taken spark plugs and check for good color when cranking. Nice blue color, but like I said I also don’t have 12v at the coil when it does starts then dies.
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Old 06-10-2019, 09:44 PM
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Does it run til you let go of the starter and let it back to the run position on the keyswitch?
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Old 06-11-2019, 07:05 AM
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Yes when it starts turn key to run it stalls out.
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Old 06-11-2019, 08:28 AM
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Originally Posted by Tiller42788
Yes when it starts turn key to run it stalls out.
Sounds like there is no power(voltage) at coil with key just turned on? use a test light to check.
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Old 06-11-2019, 08:35 AM
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Have battery voltage with the key on at the coil
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Old 06-11-2019, 02:25 PM
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Being a 98 I'm assuming it has TB-V ignition

Run a jumper wire from the battery to the + side of the coil and see if it will run
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Old 06-11-2019, 10:01 PM
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I by passed the lanyard switch was able to get you started running rough adjust the idle at carb. Now is purring like a kitten went thru forward and reverse functions and is running great. Looking forward on getting in the water test everything out. Thanks for the help
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