Head scratcher...can't figure out. Need some help!!!!

[716 John]

Great forum with a lot of great knowledge and information. I have searched this forum and could not find any threads on this subject, so I apologize if I missed a thread that addresses this issue.
2005 sx230 HO
Issue I am having- I start engine 1 with no issue and it starts right up, when I go to start engine 2, engine 2 starts right up BUT engine 1 immediately shuts off. I will keep engine 2 running and restart engine 1, and then engine 2 shuts off off immediately. I can't keep both engines running at the same time. Once I start one engine, the other shuts off. This will go on for 5 or 6 starts and then eventually I can get both started and they run great. Zero issues with the engines once they are started. I have no idea what is going on or what I should even check to find the issue. Any help with this issue will be greatly appreciated.

 

[Babin Farms]

How old is your battery? Check connections and make sure they’re clean and tight. Have you recently done any work to the boat?

 

[716 John]

I believe the battery is 3 years old. I had it winterized and stored for the winter. The winterization included oil/oil filter change, spark plug change, antifreeze flush. I have tested the battery and it is in great working order. I have been out on the boat about 5 times this spring/summer with no issues until the last 2 outings.

 

[zipper]

I agree with @Babin Farms , check the battery connections, positive and negative. One could have worked it's way loose.

 

[716 John]

Babin Farms and zipper, I really appreciate the responses. I will give the battery connections a look. Thank you

 

[zipper]

Do you have a volt meter to check the resting voltage of the battery. If so, what is the reading? Resting Voltage is with motors off and a few hours after being on a battery charger or not being on a charger at all.

 

[716 John]

zipper, I just checked the connections and they are solid. I will test the resting voltage of the battery next. thank you

 

[fireflymedic]

Well it definitely sounds like the electrical draw off cranking is shutting the other engine off. I would put a battery booster or jumper cables and another battery or to your truck to boat battery to see if it still happens. Just for shi# and giggles I'd replace plugs just in case they are wore out to the point they are borderline effective at 12+ voltage but not any lower.

 

[tdonoughue]

And is the battery tied down? If a battery is not tied down, the plates internally can crack. That will cause issues when there is vibration (like starting an engine), but will also cause issues when the battery heats up (suddenly it will appear to lose charge). Had that happen to me once (not the starting thing, but the cracked plate thing).

 

[716 John]

tdonoughue, thanks for the reply. The battery is secure to the boat in a battery tray it does not move. Plugs are new at the beginning of the season (probably 10 hours on them). I'm going to test the resting battery voltage next and then I will try using another battery or jumpers to see if the issue is resolved. Thanks for the help!!

 

[716 John]

fireflymedic, appreciate the reply. I will try using another battery or jumpers to see if issue gets resolved. thanks