Jump to content

Dead in the water


Recommended Posts

We were out for a pleasure cruise on the lake outside IBay last Saturday. I was underway when the boat just slipped out of gear, I shut the engine off immediately just in case. Then started it back up. At first I had some trouble starting it. Then she fired up. I thought "hallelujah", we're fixed. Then I pushed the throttle, the engine rev'ed but she never "clicked" into gear. I had to call Boat Tow US (thankfully the tow was covered by insurance - SAFECO).


It's back at my slip now (how that captain docked a boat in a crowded marina (light winds) by towing side-by-side, i don't know, what a pro!).


Some details:

  • While anchored in shallow water just before this happened, the outdrive may have contacted the sandy bottom, as the wake being drummed up by the traffic was significant!
  • However there was no damage to the prop
  • 2001 Rinker Fiesta Vee 24' with 2' diving dock (26' total)
  • Mercruiser Alpha outdrive
  • Engine starts but will not get into gear. 
  • Mechanic has ruled out simple prop hub. 
  • He reckons it could be the drive coupler, and I think he mentioned it could also be the drive shaft. 
  • Next step is to get her out of the water so we can investigate further.


Interested to get some thoughts on this.


As an aside, FOUR boats capsized last weekend in the area. I heard of two of them on Channel 16 while we were waiting for a tow, the mechanic told me about the other two. Crazy stuff. 

Link to comment
Share on other sites

The coupler is made out of aluminum with a rubber doughnut  [ to help cushion the shock of F/R engagement ] between the outer housing and the inner splined coupler. That will let go before the steel drive shaft.If the drive shaft has not been aligned or checked that may also add to the splines being semi worn to begin with. Couplers can be found at NAPA along with online for 100-to 150. New gimbal bearing [ while you have the outdrive off to remove the coupler , ] might be needed as well. If that starts to go it allows play in the drive shaft which then tears up the coupler. It may be a DYI job if you can get to the back of the engine where its connected to usually the flex plate. I have done it while not removing the engine on a inline 6 mercruiser , not sure what you have for a engine as you never mentioned that, probably one of the more important things to do when posting about drive line issues. You can fire her up in the water and if the drive shaft is not moving that means the coupler is shot as the FNR is in the lower unit ( bullet ) and the drive shaft is always moving to turn your impeller which might explain the hard starting as it probably was running hot with no water being pumped through it.

Edited by Bozeman Bob
Link to comment
Share on other sites

9 hours ago, Decoy Hound said:

You sure it’s not just the shifter cable?

  Op stated he was under way when " it slipped out of gear " . Once a mercruiser out drive is engaged it will not slip out of gear due to the design of the gear box. The exception might be if you hit a object at planning speed and even that is doubtful. I do wonder how the mechanic ruled out a spun prop with the boat being in the water , unless he could see the drive shaft not moving while the engine was running.


Link to comment
Share on other sites

I just went through this.


Start motor and see if the drive shaft is spinning on the back of the engine.  If its not, then its the engine coupler.


If it is spinning, then:


Shift in and out of gear.  If you dont hear the normal clunk on the shift then its a completely spun prop (it should still catch a bit which would allow you to hear the clunk but sometimes it gets completely spun) or the vertical shaft or gears stripped in your outdrive.  To further diagnose, take the boat out of the water. 

Remove the outdrive.

Manually put the drive in gear.

See if you get the prop to lock both ways.

If it locks then take a long screwdriver and spin the yoke on the front of the drive.  

If it just spins and doesnt lock or spin the prop, then you have yourself a junk outdrive and you will have plenty of silver flakes in gear oil (this is what mine did).

Link to comment
Share on other sites

Thanks for v much for all this great info! 


Engine type: MerCruiser 5 litre Thunderbolt V Ignition (2001 boat).


He checked the prop hub while in the water. Me and his guy stood on the bow while he reached down to the prop. He was able to poke around that way. Since he could not confirm what it was - we're going to take it out of the water. (The damn tow boat at my marina is also goosed, so I have to get somebody down to tow me to dock :dull: ). 


I did not hit anything while planing. I was moving through the water, just driving through some wake from another boat (2 or 3 feet wake), nothing major, and all of a sudden it appeared to slip out of gear. I couldn't tell if there was a 'breaking' noise, there was definitely a noise, but I think it was just the engine revving since the throttle was open and no gear engaged (it all happened quickly, my instinct was to shut the engine off immediately). There may have been other noise that I didn't hear/ notice in the moment. 


Once I got it started again, I tried many times to get it in gear (FW or RV), as did the mechanic, we could not get the magic 'cluck' sound.


Thanks again for all the info.


Edited by WebsterWaters
More info
Link to comment
Share on other sites

In a lot/most cases you cannot just grab the prop with your hands and try to spin it to see if it's spun. It might take a prybar or 2x4 to get it to move , so I wouldn't trust what the "mechanic " came up with unless he did that which it sounds like he didn't.

Link to comment
Share on other sites

Same thing happened 2 yrs ago to me in Sept.  I have a 305 V8 mercruiser in my PY.  Anyways it was what I ended needing is a new coupler, pinion gear, main shaft and upper unit and it was expensive.  I  had Mikes Mobil Marine fix it and I towed the boat there.  Pretty involved repair and on a V8 Merc I know you have to pull the engine.  Good luck.


Link to comment
Share on other sites

Finally I have some updates! She is back in the water.


So - a few years back the previous owner hit the bottom of whatever lake he was on. They installed a new after market lower drive. Which I did know, but did not realize it was an aftermarket vendor (versus a Mercruiser lower drive). The problem this time was simply wear and the lower drive was no longer functioning. (I'm not sure which shaft or gear exactly was worn out). So I had two options - 

  • Use the warranty for the same after market part (which only seemed to last just under 3 years). It would have been 100 bucks for shipping, then they would have taken 3-4 weeks to process it and send out the new part.
  • buy a used Mercruiser lower drive for a few hundred bucks and be back in the water this week. 

I chose option B - it cost me a few extra dollars, but I would have the boat for the remainder of August/ early September. 


Thank you all for the advice! 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...