1992 9.9/15 HP Jumping Out of Gear

[scout-j-m]

I have a 1992 Johnson 9.9 HP with a 15 HP carb. It is relatively new to me but it is in great shape, gas good compression, and runs well. I have it currently mounted on a 1648 Alumacraft flatbottom with a 10" pitch prop which is a good load especially with an extra guy. I have put maybe around 10 hours on it since buying it about 4 months ago (don't cruise much, just fish).

This weekend my dad and I took it out to the river to fish and ran it a few miles and hard (WOT/ 6200 rpms) over the course of the outing. No issues. Before heading out, I trailered the boat to adjust my newly installed SI/DI transducer to cut back on the rooster tail it was throwing and then put it back in the water to test it out. I ran it solo and after a short stretch at WOT it jumped out of gear I think. I went to neutral, then back to forward and took off back to the ramp where it happened again. This is the first time it has done it for me and I have had it up closer to 6900 rpms too with no issues when it had an 8" prop on it and just me in the boat.

My question is if a mis-adjusted shift linkage could cause this? ...Because mine is off a little. Currently when I am in forward gear and shift it into neutral, it stays in forward unless I tweak the shifter handle just a little bit farther towards reverse. Shifting from neutral to forward is never a problem. It shifts from neutral to reverse and back to neutral just fine as well. From my understanding this is not what is actually causing it to jump out gear but probably what caused the clutch dog teeth to wear from not having a clean disengaging when going from forward to neutral. If that is the case I guess I will need to dive into the lower unit and see for sure and fix it. Regarding that, I was also wondering if it is possible to simply reverse the clutch dog so the worn end engages the reverse instead since it is used much less frequently and at much lower rpms?

 

[racerone]

Clutch dog looks like it can be turned around.------But it can not be turned around.----Groove on one side must go towards the forward gear.------Check your adjustment.

 

[scout-j-m]

Thanks. I will recheck the adjustment some evening this week but probably won't be able to test it back out on the water until the weekend. I'll post the results.

 

[flyingscott]

Did it bang out of gear or just slip. Could also be a spun hub. To adjust the lower shift rod in the lower unit. Turn the shift rod until tight and back off only enough enough to line up with the upper rod about 1/4 turn. Usually a dog will jump out of gear right before the boat planes but not always.

 

[racerone]

There is an adjustment at the powerhead too.

 

[raczekp1]

1. https://www.youtube.com/watch?v=YGWHrTYeGFQ

2. https://www.youtube.com/watch?v=DfHblcAVDYw

 

[scout-j-m]

Did it bang out of gear or just slip. Could also be a spun hub. To adjust the lower shift rod in the lower unit. Turn the shift rod until tight and back off only enough enough to line up with the upper rod about 1/4 turn. Usually a dog will jump out of gear right before the boat planes but not always.

I don't recall a bang or any unusual noise. I was just going along and it all the sudden deccelerated and the rpms stayed high. In a sense, it acted like you would expect a spun hub to act, however, I was up on plan and going WOT before it would do it. Also, even when it was doing this I tried throttling back to idle and then slowly giving it gas again while still leaving it in gear and it was still not accelerating any.

I will check both the adjustment at the powerhead and at the LU like you mentioned before trying it out again.

 

[scout-j-m]

1. https://www.youtube.com/watch?v=YGWHrTYeGFQ

2. https://www.youtube.com/watch?v=DfHblcAVDYw

Thanks!

 

[flyingscott]

Check for the spun hub first. When the dog goes bad it makes a bang when it jumps out of the gear.

 

[scout-j-m]

Check for the spun hub first. When the dog goes bad it makes a bang when it jumps out of the gear.

I will do that.

I've never personally experienced a spun hub. Is it possible that it doesn't slip at all until it hits a certain rpm or load and then it doesn't "grip" again until I shift to neutral to allow the prop to totally stop? That's another thing that led me to believe it was out of gear. I guess if it does it again I could shut the motor off with the gear select still in forward and tilt the motor up to see if the prop feels totally free to spin like in neutral or if the hub may be what's allowing it to move....which would still provide some resistance I would think.

 

[flyingscott]

To check for a spun hub scratch a line across the hub of the prop, across the metal and the rubber. Then take it and run it when it does it again see if the line moves. You probably won't be able to turn the prop by hand even if it is spun. That is exactly how spun hubs work going along and all of a sudden revs up. When you slow down in neutral the hub will regrab the prop and work again. But it will only get worse as time goes on.Bad shifting dogs tend to sound like a gunshot when they pop out of gear.

 

[scout-j-m]

To check for a spun hub scratch a line across the hub of the prop, across the metal and the rubber. Then take it and run it when it does it again see if the line moves. You probably won't be able to turn the prop by hand even if it is spun. That is exactly how spun hubs work going along and all of a sudden revs up. When you slow down in neutral the hub will regrab the prop and work again. But it will only get worse as time goes on.Bad shifting dogs tend to sound like a gunshot when they pop out of gear.

Gotcha. That would make sense then. I heard no bang or pop and this prop came off of a 1982 model motor that had been in storage for a while before I bought it. Also seems to be the original prop to the motor. It would make sense that the rubber hub has gotten weaker over time and my use of the prop here lately has put some stress on it that may have finished it off.

 

[scout-j-m]

Put a mark across the hub and tested it out yesterday. I didn't have any of the issues mentioned above indicating it was slipping or jumping out of gear. When I went to swap out props and check the marks they were hardly visible, but it appeared they may have shifted ever so slightly. I went ahead and put on my other prop and again had no issues.

I'm going to clean up the prop hub area of the grease which was making it hard to read and remark it. then next time I go fishing I will check it again.