Mercury sport jet 200 optimax

[DanJ]

New to the forum and desperate for help. I have a 2001 Nort River inboard jet boat. It has a Mercury sport jet 200 optimax. The engine starts fine but as i throttle up it takes off just fine most times but randomly shuts down and alarms but instantly fires back up on its own. It's just a split second. Took it to 2 mechanics locally they said the code says low voltage. Had the starter and alternator rebuilt. Replaced the water pressure sensor and the throttle positioning sensor. New battery as well. Any ideas?

 

[tdonoughue]

Low voltage I am guessing puts you in a chicken n egg scenario. If the engine cuts out for any reason (let's say fuel interruption, just for fun), the engine dies, the generator/alternator stop, the voltage gets low... So I am betting your problem is figuring out whether the low volt is causing the engine issue or the engine issue is causing the low volt. Just on odds, I am betting the latter. Which is basically no help (other than to say don't just look at electrical), because it could be plum near anything.

I guess were it me, I would be starting with all things electrical--looking for loose connections, corroded connections, etc. Could be in the engine electrical (e.g. plug wires, packs, etc.) or other electrical (e.g. fuel pump, ignition switch, etc.). Any of those could be reacting to a bump while you are running, cutting out for a second and reconnecting...

 

[DanJ]

Thank you for the response. I didn't mention it, but I have checked and cleaned every ground and checked all of the connections/ plugs I could find. But that is a good point. If say the fuel pump is having an issue that could cause the engine to drop RPM's and cause low voltage. I will see what I can find. Thanks again.

 

[tdonoughue]

Sure. I see you're new, so we sure would appreciate a) your letting us know how it goes and b) your sticking around and checking out the other parts of the site...