2006 Mercury Optimax 115hp loses volts and won’t plane after using trim

[Bucketdad7276]

After using trim at near wot boat starts to misfire, won’t go over 3500 rpm’s and won’t plane again. The battery is new and there is a separate battery for trolling motor. It ran great first thing in the morning but began cutting out when I would trim. Later in the day it wouldn’t get up on plane at all. Volts drop from 13 to 11. Serial number is 1B288873. We are thinking alternator but appreciate any thoughts. All connectors are bright and shiny as well as securely connected.

[JOE54]

i too think that if batt is big enough and tests good , volts should come up higher also

[SilverFox579]

Sound like you may have a charging issue or a battery that does not meet engine minimum required 800 cold cranking amps (more is infinitely better) or both.

I'd do two things, fully charge new battery, have it load tested, reinstall in boat, and start engine on hose or in water then after 5mins check voltage at the battery using a DMM. Report back with results of load test (they should provide you with actual cold cranking capacity numbers) and voltage observed at battery.

[Topwater 2]

That 115 should have a 1000 cca battery.

[Bucketdad7276]

We are back on the water! A new alternator and cracked fuel grommet replacement seem to have fixed the rough idle as well as the voltage problem.

[JOE54]

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