1985 Mercury 850 prop will not engage in gear

[headen]

Had a little accident with my outboard. I had it running in my yard and went to run in the house for a sec, came back and discovered my trim had let the motor down. The prop had stopped turning because it was on the ground and the motor was still running. My prop unscrewed itself and now I am having a time getting my motor to engage forward and reverse. I have taken the prop off and the shaft that goes with it everything looks good. There are no stripped gears or anything. When I start it, it sounds like it is trying to engage but doesn't. Any suggestions?

 

[radsrh]

Re: 1985 Mercury 850 prop will not engage in gear

1st a question, why was the motor in gear running on the muffs? WITH the motor not running try to put it in gear and see if the prop shaft turns by hand, if not pull the plugs and turn the flywheel in the correct direction and see if the prop shaft also turns in the correct direction. This will give you a quick overveiw of the gear box to see if there is major internal dammage. I also would drain the lower unit and see how much, if any metal is in the oil. What type of prop was on the motor? SS or aluminum.

 

[headen]

Re: 1985 Mercury 850 prop will not engage in gear

hmm...the motor was in neutral with the muffs, but I always have a slow turning of the prop. I have an aluminum prop. Also, I will try to see if I can turn the prop WITH the motor off and with it in gear by hand. I am totally new at outboard repairs, so forgive my ignorance. When you say pull the plugs and flywheel...can you explain what to look for?

 

[mellowyellow]

Re: 1985 Mercury 850 prop will not engage in gear

at the very least you have spun the rubber hub and that<br />will need to be replaced.<br />hope that's all it is <br />good luck,<br />M.Y.

 

[dkondelik]

Re: 1985 Mercury 850 prop will not engage in gear

Hi Headen,<br /><br />Take the cover off of the motor. Look for the thick black wires. Follow them to the ends. At one end of the wire you'll find the (spark)plugs. <br /><br />The flywheel -BIG CAST Aluminum wheel sitting on the top of the motor. Get (purchase or borrow) a Gear Puller or Flywheel puller. Screw the extra screw through the radial holes in the Puller, down into the Flywheel, Then use the appropriate sized wrench to turn (clock-wise) the BIG bolt in the middle of the puller. Thi will pop the flywheel off.<br /><br />Sorry if I was too remedial but I don't know your mechanical/Technical background.<br /><br />Good Luck<br />HAVE FUN!

 

[Ken G]

Re: 1985 Mercury 850 prop will not engage in gear

Ok, I'm confused but I'll try to help anyway. Mercury made the 850's from 1973 thru 1977, my manual does not list any other 85 hp models between 1965 and 1992. If in fact it is an 850 from the mid 70's then it is similar to my '77 model 500. My prop does spin slowly at idle while in neutral on muffs. The prop can easily be stopped with a stick or even my toe. If the prop was stopped while in neutral there is not enough torque to spin the prop hub. I also can't understand when you said the prop unscrewed itself. The prop and propshaft are splined and can not 'unscrew'.<br /><br />Anyway, you can check to see if your prop is engaging without running the motor. With the motor in forward the prop will not spin counterclockwise and will 'ratchet' while you turn it clockwise. In neutral the prop will turn either direction. In reverse my prop will not turn either direction but some will turn both directions about 30 degrees. <br /><br />You can also turn the motor by hand to check shift engagement. You need to remove the spark plugs but you do not have to remove the flywheel. Remove the wrap around cowl and the top hood from the motor. Remove all spark plugs. The flywheel is located on the top of the motor. Use a 15/16" socket in the center nut of the flywheel to turn the crankshaft clockwise. If the motor is in forward the prop will turn clockwise. In reverse the prop will turn counterclockwise.<br /><br />If you suspect your prop hub remove the prop and do these tests by looking at the propshaft.