Low Battery Voltage

[notshort]

My 2000 Seadoo Islandia is powered by a Mercury M2 240 EFI. Couple of times this summer I've had trouble getting the motor re-started after shutting down (usually after low speed/idle ops). Starter would engage but engine wouldn't start. I haven't used the boat much at all this summer and I suspect the batteries discharged somewhat due to lack of use and high outside temps.

I have two Interstate deep-cycle batteries installed...one was purchased in 2011; the other in 2013. Both were alternated on a smart charger over the winter.

I suspect my starting problems are the result of low battery voltage. The tech manual says that operating engine at a low RPM for an extended period of time can cause low voltage. Also says that low battery voltage can cause EFI system to deliver fuel inconsistently and that EFI system requires a substantial amount of voltage to function properly.

Can somebody explain why this engine requires so much voltage and what it's being used for...tech man really doesn't say much about that. Thanks in advance.

 

[Dr Honda]

At low RPM's... you don't put out much power for charging... but are using power at the same rate. Also... wet batteries don't hold a strong charge when they sit. This is typical for all systems like this. (even your car/truck) But this situation is generly aggravated with a "Toy" since it sits around.

SO... charge the batteries... and enjoy the boat.


Oh... as a final FYI... there's no reason to have "Deep Cycle" batteries in your boat. You need at least one "Starting" battery. A deep cycle battery doesn't like a heavy amp draw, and the voltage will sag down when asked to do so.

 

[notshort]

Dr. Honda;
Thanks for the info...much obliged.

 

[Coastiejoe]

Also, with Seadoo boats they really like to have the Blower Motor run after you stop. The engine has a hard time starting on the stale air that is trapped within the hull at slow speeds. Also, there is a safety concern by nor running the blower. If there are gas fumes in the hull it can be an "explosive situation" if spark was to ignite the the fumes..