500 efi starter issue
 

We had a starter go bad on the starboard engine. I replaced it with a new Mercury starter, not a rebuilt one. Now when I turn the key it will turn the engine over once then the starter will spin free, let off of the key it does the same thing. I checked with the dealer I bought if from and they confirmed I have the correct starter. Does anyone have any suggestions as to what could be causing this to happen? I guess I'm going to have to pull it off again.

I'd say weak battery, or bad new starter.

I thought about a weak battery also, but the onboard charger says it is fully charged. I will put the volt meter on it tonight.

Keep in mind, that if you have a bad battery, it could still hover around the 12 volt mark, but with a load, drop fast. I'd have someone try to crank the motor over while you have a meter on the battery. I'd check to make sure your cables are on tight on the starter as well, may have a voltage drop there.

That seemed to fix the problem. Two new batteries and it started first time without even struggling.

I have not posted on this thread in sometime, but I'm still having starter problems. I replaced the new starter with my old one that was rebuilt just to make sure it was not the new starter I bought. The same problem that I had to begin with it will turn over a couple times then free spin, like it is kiking out. I let off the switch and try it again and it will fianlly fire. It has always started just takes a couple times. One thing I would mention is that on the same engine I'm having some gremlins, the tach is sort of jumping around. This will come and go though, sometimes it will be fine then next time you look at it, it will be jumping up and down. Any suggestions would be great.

Oh I will mention that I have swapped the tachs to rule out that. Still does it on the same tach once I changed them so it isn't the tach.

did you check to make sure you are not getting water in the
motor?? pull the plugs and see if it spins free.
cmi exhaust(if that is what you have) is good for cracks

When having any kind of starter probloms especially on a boat you have got to make sure battery voltage is sufficent and
both neg and pos cable integrity is intact. Battery must be
at least 12v and capable of a current loads of at least 400
amps during intial starter rotation. The cable connections must be appropriate and dont be fooled by what looks like a
a solid crimp. Some times if you lightly pull on the cable they
will slide out of what looked like a good crimp connection
at the terminal end. Never underestimate the importance of
ground connections as well as B+. I have seen many a tech
replace a starter only to find out that the core problom was
a connection. And never by the cheap, knock-off, pacific rim
built starters. YOU GET WHAT YOU PAY FOR

check the starter bolts to make sure they are not bottoming out on the shoulder of the bolt and not let the starter tighten up. you might also need to shim the starter, the merc number for a starter shim is 15-8172721. with the starter drive kicked out messing with the teeth on the flywheel you should have about .030" clearance

I think you might have something here. Now that you mention it that could very well be it. If the boat sets all week without being fired it will do it. But if you start it the next day it will not do it. It could have a small hole and it takes it two or three days to get the water in the cylinder. I will let it set the rest of the week and pull the plugs to see if any of them have water in them.