140 Mercury 2 stroke starter gear spinning, but not engaging flywheel

[79bomber]

My 1978 starter will spin very fast, but the gear/rod will not kick up onto the flywheel to turn my engine over. Battery is at full charge. Do I buy a new starter or is it something else that can be repaired. Looks pretty simple to take off.

 

[racerone]

I would never rush out to buy a new starter !!-------Did it suddenly start misbehaving ?-------Battery hooked up properly ?----------Take this starter apart for inspection.--Could be as easy as a new set of brushes.----Of course if money is not a problem than a new starter is nice to have.

 

[DavidMoore]

Without knowing your exact starter

Most likely the bendix is stuck which can be repaired by removing it and cleaning both the the bendix and shaft, you should be able to make the bendix climb the shaft just by turning it with light finger pressure.
If the bendix will climb the shaft then it could be the motor is spinning backwards, the battery could be is hooked up wrong (as mentioned above) or the starter has already been taken apart and the stator (the black tube) put back upside down.

One of the best things I ever did on my engine was stripping and cleaning the starter, it really improved the cranking speed and starting is so much easier now.
15 mins work if you prepared a little tool to keep the bushes in place on reassembly. The manual (or you tube) will show the tool you can make yourself really easily.

 

[Texasmark]

BEFORE YOU DIDDLE THE BATTERY CONNECTIONS READ THIS.........

The battery is to be connected to the engine with the - terminal connected to the engine block via the black lead. This may be through the starter housing and connection to the block is via that or a jumper wire but - is negative, ground, return, zero volts and anything else you want to add.

+ is the Red lead and it goes from the battery + lead (12v source voltage) usually to the input terminal of the starting solenoid which supplies voltage through the solenoid (when energized) to the starter, but is used as a junction point for 12v distribution throughout the engine and remotes.

If you reverse your battery terminals from what I posted, even for ? of a split second you will burn up the negative diodes in your battery charging circuit in the engine. So look before you leap. If your problem IS that the lines are reversed, your rectifier/voltage regulator doesn't work any longer!

Follow David's mention of the 2 finger test on the bendix with the engine off and making no attempt to start it. Spinning fast may seem like it is working ok, but for the Bendix to work when the solenoid closes, you need about 150 amperes to SLAM the Bendix into the flywheel.

Check your voltage across the starter when you attempt to start it; one lead on the ⅜ stud on the side of the starter and the other on the starter case....metallic band if composite housing. When you hit the starter you need to have at least 10v present while delivering the necessary current. Course when the Bendix misses connecting with the flywheel, you aren't using anywhere near 150 amps so you ought to read close to the full battery voltage.

 

[79bomber]

I have finally gotten around to this starter again. I have taken it off and when bench tested, the bendix will not climb the shaft (My electrical hook-up is fine, but thanks for the insight). I think the cleaning will happen now and will see about the brushes while inside. I have never done any boat starter repair before, but this doesn't seem too difficult. I have only worked on cars. Any insight is appreciated, as always.

 

[racerone]

Take an ohm reading from commutator to the shaft.----On a digital meter it should read infinity.---A piece of sheet metal with a slot makes assembly of brushes easier.

 

[79bomber]

I finally got to clean my starter and it works great! Thanks to everyone for your input. (Looked up a video on it and a guy is taking apart and cleaning one just like mine, 1979 140 Mercury 2 Stroke OB)