1998 Force Mercury 90HP Starter Engages Only Briefly

[Oldsaltydog]

I have done quite a bit of background research, but I have not found an answer to my particular starter problem yet. Especially when the outboard motor is cold, the starting gear will run up the shaft just fine, but it either will not turn the motor over or it will turn it for a second or two and drop back down again. After repeating this process two or three times, the motor will eventually start. The battery is new and it seems to be charged okay, but I have to admit that I have not checked out all the starting circuit connections yet. (But I have done tons of other repairs on this new purchase.) Any suggestions?

 

[JB]

Re: 1998 Force Mercury 90HP Starter Engages Only Briefly

Howdy, EBG.<br /><br />You need to troubleshoot the entire high current circuit. It is very likely that you have a low resistance fault in a cable connection. Prime suspect: where the ground cable from the battery connects to the engine block.<br /><br />Check out the starter circuit troubleshooting guide in the "Outboard wont start" article in the Engine FAQ section.<br /><br />Good luck.

 

[eurolarva]

Re: 1998 Force Mercury 90HP Starter Engages Only Briefly

As JB mentioned check the wiring for corrosion and tight connections. If connections check out I would first take battery in to an auto parts store and have it tested. A battery can look good and still not have a good cranking charge. For a 90HP you probably want a minimum of 575 Cranking Amps. If battery is fine the next step would be to take starter apart and check the brushes. The hardest part of this is getting the starter back together again because the brushes are spring loaded.<br /><br />Good Luck

 

[Oldsaltydog]

Re: 1998 Force Mercury 90HP Starter Engages Only Briefly

Thanks for the advice. I did many of the tests you had recommended -- but everything was fine. The problem turned out to be the Bendix gear and spring caked with old gunky grease. After a good cleaning, now the starter works just fine.