Puzzling Starter Problem

I'm baffled by this one, and I sure would appreciate your thoughts on this phenomenon.  The motor is a very low hour Mercury/Force 90 HP three cylinder, triple carbs in a 1994 Regal "Rush" jet boat.  It seems that when the battery is really totally charged up, it will start instantly, but if the battery is even a little down, as after allowing the boat to sit idle for a week, the motor will crank like crazy, but not start...and...the bigger problem is that you can hear a loud metallic knocking...like as though the starter bendix was slamming the starter gear into the ring gear and then dropping off, and then hitting it again, repeatedly.  The banging rate is at least once or twice per second, and through all of this, the motor is cranking quite fast...like it should start easily.  Do you have any idea what the real cause of the banging may be, and why the no-start, and how to correct it?
Thanks so very much for your help.
Jim

Jim,

Sounds like the prime system is not working. That is why it doesn't start. The banging is the bendix working the flywheel during the compression stroke. Nothing to worry about.

Randy

 

 

Please submit whatever questions you have to IHRTechTalk@yahoo.com.  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Thanks,
Mark C.

 

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