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1986 Johnson 120 VRO

W

Whalermon

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I was cruising down the river last month when I heard something like the lower end of the engine hit something in the water. The boat slowed and I throttled up and the RPM increased and the engine sounded fine, however the boat would not go over 5 +/- knots. I limped back to the launch and figured I spun the prop by hitting a submerged log or something. I brought the prop to my local prop shop to have a new doughnut installed and they told me they tested the prop and it was fine. I reinstalled the prop and launched the boat, the engine runs and revs fine but the boat will not exceed 5 knots. Has anyone experienced this?
 
Drain your gear case oil and look for bits of metal. My guess is you've either sheared gears in the lower unit or snapped the prop shaft when you struck the submerged object. Another possibility, although unlikely, is you could have stripped splines on the drive shaft where it mates to the crankshaft. Whatever the issue, it sounds like you have deeper mechanical issues that are going to be costly to repair.
 
??----A sheared flywheel key would throw out ignition timing.-------Or bring your motor over I fix it very easy.----Something went wrong with your motor and some simple inspections / trouble shooting should find the problem.
 
Post # 1 indicates that the OP may have " hit something "------If flywheel nut was not torqued properly it may shear the key.----I believe the OP will sort his problems out.----Trouble shooting is so easy.-------Good luck with it.
 
1986 had the std V-4 gearcase....most likely broken driveshaft at top of pinion. See quite a few of these on the small bore loopers.
 
I drained the gear case this morning. The gear oil was clean with no signs of water intrusion and no metal, not even filings on the magnet. I have to think that the guy who tested the prop hub is mistaken so I will have it tested at another shop. I also talked to the local OMC dealer, he said that if I sheared off splines on the prop shaft it would have made loud grinding noises but it didn't, the motor sounded normal all the way home.
 
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