Suddenly boat stopped going into gear. Help!

[jasondainter]

Hi folks. Ive not been having a good week! Id finally fixed my Johnson 55hp from 1979 which had a bad lower carb (gasket missing) for 2 years and it was now working a dream... For a few days..

Occasionally when driving fast I could hear a loud 'bump' sound from engine. It was far and few between and ignored it till it today suddenly got a lot worse after 10 minutes driving at WOT (23 knots)

Stopped in the water and then after this I wasnt able to engage the gears at all. Like something had 'slipped' in the gear system.

Ill post a video in a moment..

I was just able to play with it enough to engage some forward gear enough to get the boat to a ramp.

I have rennovated the whole lower unit 2 years ago and replaced a bad clutch dog and forward gear.

Can anyone help out where I should start? I guess I'll have to take off the lower unit again but is there any other things I can check before starting that painful process again?...

 

[jasondainter]

Video:

 

[jimmbo]

The case likely has to come apart again. Are you one who slams it into gear or do you ease it into gear?

 

[jasondainter]

thanks for quick reply.
In the video i’m not actually touching the lever at all it slams by itself (eg ‘slips out’)

i was speeding along WOT then it suddenly slammed and went high revs and felt like the propellor was spinning.

after the video it was 100 times worse it was start up and sit still but when pushing it even into idle it would struggle to get that ‘crunch’ when the clutch dog bites. I managed to get it to bite forcing it a bit (had to as was stuck out on the water), but then after a few seconds going forwards it would slip and same thing it would suddenly stop going forwards as if the propellor wasn’t spinning.

i’ve been reading about spun props, and if this could apply?

 

[Faztbullet]

Needs new gear and dog or a driveshaft

 

[jasondainter]

Ok thanks I'm on my way to fetch it now (had to get a 150 dollar taxi home )

Out of interest what makes you assume new gear/dog or driveshaft over a spun prop? Was going to rule that out first but is there something from symptoms that makes you think its not that?

 

[clemsonfor]

Ok thanks I'm on my way to fetch it now (had to get a 150 dollar taxi home )

Out of interest what makes you assume new gear/dog or driveshaft over a spun prop? Was going to rule that out first but is there something from symptoms that makes you think its not that?

Cause of the clunking and jumping out of gear. That's just like the clutch dog slips and is spinning then all of a sudden it will catch again Spinn ng the prop then stop.

I don't personally think it's a spun prop. Could be like he said a stripped driveshaft that's spinning and catches all of a sudden.

The lower unit is where that type stuff happens. Only other thing would be if it's out of adjustment for going into gear and not going in all the way due to misadjustment, but at this point it's probably to late to correct that as if that's an issue it has destroyed the dog and gear already.

 

[jasondainter]

Got it apart. Heres my next question notice shift rod was actually very unusual and as I was taking apart it just lifted out. Gears so far don't look that bad. Any ideas?...

 

[racerone]

Just take it all apart.----Problem will then be obvious.

 

[jasondainter]

will hopefully get time tonight

 

[jasondainter]

Turns out the shifter lever (part 320120) was totally broken inside there. Will try get hold of a new one. Anyone happen to have one in US they can sell me/post to Sweden.

Any ideas why this happens?

 

[jasondainter]

So this is the part I need https://www.marineengine.com/newpar...ass_title=0320120+:++<p><br+/>Shift+lever</p> but it seems quite hard to get hold of.

i found this one on ebay looks visually identical but part number is 322938 https://www.ebay.co.uk/itm/382247067370?epid=19007102662&hash=item58ffb35eea:g:If8AAOSw9fRZ252O

Any ideas if this is the same part?

 

[jimmbo]

Attempting to shift into gear, without either the Propshaft or the Driveshaft rotating is likely the reason.

 

[jasondainter]

Attempting to shift into gear, without either the Propshaft or the Driveshaft rotating is likely the reason.

thanks

 

[jasondainter]

So this is the part I need https://www.marineengine.com/newparts/part_details.php?pnum=OMC0320120&pass_title=0320120+:++<p><br+/>Shift+lever</p> but it seems quite hard to get hold of.

i found this one on ebay looks visually identical but part number is 322938 https://www.ebay.co.uk/itm/382247067370?epid=19007102662&hash=item58ffb35eea:g:If8AAOSw9fRZ252O

Any ideas if this is the same part?

Thats a totally diffewrent part now I look closer.

Seems impossible to get hold of part 0320120 even in the US.

 

[jasondainter]

I found one! A nice person from the Evinrude & Johnson Outboards Facebook group is giving it to me for free (lives just an hour from me in Sweden, what are the odds!).

 

[clemsonfor]

I found one! A nice person from the Evinrude & Johnson Outboards Facebook group is giving it to me for free (lives just an hour from me in Sweden, what are the odds!).

That is crazy! But there are a lot of these engines out there and all over the world.

 

[jimmbo]

And likely a lot of broken linkages, so the inventory of new parts is small, or low

 

[jasondainter]

Attempting to shift into gear, without either the Propshaft or the Driveshaft rotating is likely the reason.

I had no idea that putting the boat in and out of gear with engine off would do this kind of damage. I have to admit i've done that a lot because I had a recent carb issue and was testing the hell out of it. I guess lesson learned and I should only do that with muffs on and engine running when boat is out of water.

I heard that when driving the boat on trailer you're supposed to put it in fwd idle or reverse gear to stop the propellor spining when on the road. Is that still advisable or should I keep it in neutral or something else when driving?

 

[jimmbo]

I have never seen any requirement to do so in any Owner's Manual.

As to why I stated not to attempt to shift into gear without either the Propshaft or Driveshaft turning, is due to the design of the Gears and the Clutch Dog. As you have seen when looking at the Parts, the Gears have what are Troughs with Stops, where the Teeth on the Clutch Dog engage when the Shift Mechanism is operated. When the engine is running, those are Troughs are open a good portion of each evolution of the Gear, and the Dog can engage. However when the gears are not turning, there is the chance the Dog will contact the Stop, and not be able drop into the Trough. With the Dog unable to fully move, that puts very large amount of Stress on the Shift Linkage as you keep on pushing the Shift Lever towards full engagement, so you can operate the throttle linkage. Results can be bent or broken parts in Shift linkage/mechanism. Simply rotating the Prop by hand/foot as you try to shift a non running engine, will expose the Trough.
Some motors will use gears that have Ramps instead of Troughs, Mercury for instance, does so with the Forward Gear, and the Clutch Dog is moved by spring Pressure into gear, not by direct connection to the Linkage. However the Reverse gear is usually a Trough type, so shifting a Merc into reverse while not running requires the spin the prop routine.

Edited to reduce spelling/punctuation errors