Help from the motor-heads

[ratso]

My buddy has a 9.9 Merc that won't turn over. If anyone has any ideas, let's hear them... THANKS.

It is a 2003 Mercury 9.9, electric start 4 stroke "big foot" model.  It was running last year just fine.  As to having it serviced, it has never been touched.
Everything under the hood is enclosed in plastic covers, that I have not tried to get off.  The does have compression when you attempt to turn the prop in gear.
The oil is clear and full. It hums when you try the electric start, but will not turn over.

[Big Brother]

Sounds similar to the problem i had on my 90 Merc 2 seasons back.Was a fairly minor repair as all that was needed to repair it was a new starter drive gear.

[basser85]

If it hums but will not turn over it sounds like the battery needs to be charged. Does it have a rope start if so can you rope start it? Also make sure your kill switch is hooked up.

[Coldfeet]

First thing you need to do is get the covers off. If you can not pinpoint where the humming is coming from we can not help. Sounds like you got power to starter motor or soliniod maybe starter motor is just spinning and the drive gear is hung or not enough power to send starter gear to mesh with the flywheel. Or could be drive meshed with flywheel but not enough juice to spin engine over. With spark plugs out of engine try it see if it spins then. if not you need to back track to the starter itself if thats ok and the drive ingages its ok go to the battery and test it to see if it isnt shot. Jump it off car or truck to see if that works. If starter is spinning soliniod switch is ok. If starter motor is hot you might have a short in starter motor. Also make sure you got the battery cables on the right way.

[tbfisherman]

 Hi Coldfeet

 I had a similiar problem with my Starter just humming with my Evinrude Outboard Motor and it turned out to be a faulty Ignition Switch.
 Hope it is a simple fix so he can get fishing soon.

[tbfisherman]

 Sorry.... Hi ratso

[double-aught]

lots of good things to check already listed.
give a good look at the cable connections. looseness or corrosion can cause these symptons.
if thats ok, check the battery charge. a 9.9 should turn over easily, and i'd bet there is a way  to hand crank it, to see if it will run.
good luck.

[woodfolks]

If it was stored wrong over the winter
oil could be in the crank case. If you can turn it with a
pull cord, take the spark plug out and turn it over a few times
if oil comes out you may have to service it.

I stored my 4 stroke the wrong way and had to have it serviced
sounds like the same thing

[trebbled1]

make sure you have a good ground, like double aught said check your cables and connection. a bad or weak ground will cause this problem also. let us kow what you find, good luck

[crappiekiller315]

i had a similar problem the other day???
 twice after running it for awhile jumping from spot to spot.. when i went to start the engine all i got was rrrrrrrrrrrrrrr???
 turn key off then try to start again and starts fine is it possible to get a flat spot on the starter like you would in a vehicle starter???
or could it be something else i also noticed when i first started the motor it did not want to spit water out for awhile when it normally it spits almost instantly only did this once after that it was fine ??

[BoutTime]

Have you checked the iboats.com website?

Theres all kinds of boating/engine boards there and alot of knowlegable guys there to help if you cant find the answers through searching. Its a good spot for info.