# F70 Reverse Gear issue



## efi2712micro (Sep 17, 2015)

Hi folks - not sure how to title that thread 😁

went fishing on the south Texas coast and had a blast the last 3 days. Coming back to the dock today, I put the engine in reverse coming to the dock and heard a weird noise. When going into reverse now, it feels like the gear rattles until I go further on the throttle and then it latches on and jumps in reverse on high speed. Never had that happen before. Now it does it all the time. Going forward, no issues.

Time for an engine specialist to look at it or something I should be looking into first?

thanks for any help

eric


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## Smackdaddy53 (Dec 31, 2012)

Clutch dog possibly


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## efi2712micro (Sep 17, 2015)

Thanks Mack! I had to google that one 😁! This is exactly what it is acting like. Can this happen only in reverse and not forward or should it affect both?big job to replace I assume? Is it ok to operate as is for now


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## Smackdaddy53 (Dec 31, 2012)

@JC Designs can tell you more, he’s the Yamaha tech. If it were me I would take it in.


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## JC Designs (Apr 5, 2020)

It can certainly happen in one gear or the other. The clutch dog slides fore/aft on the prop shaft splines between forward and reverse gears. The dog is what locks into the gear. I normally attempt to walk folks through these things but this can get pretty involved with tear down so I am going to recommend taking it to a shop for diagnostics.


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## Frank Ucci (Jan 20, 2019)

Check your shift cable and linkage.


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## BrownDog (Jun 22, 2019)

Frank Ucci said:


> Check your shift cable and linkage.


this would be my first check as well before going further


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## mwolaver (Feb 6, 2014)

Frank Ucci said:


> Check your shift cable and linkage.


So what's first, simple check look like? Disconnect cable linkage under the cowling and see if the engine shifts correctly? Always check simple first.


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## Smackdaddy53 (Dec 31, 2012)

mwolaver said:


> So what's first, simple check look like? Disconnect cable linkage under the cowling and see if the engine shifts correctly? Always check simple first.


I doubt the linkage moved, to physically adjust the linkage it has to be unclipped and screwed in or out to make it longer or shorter. Stranger things have happened but I think it’s a mechanical issue in the gearcase.


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## JC Designs (Apr 5, 2020)

Smackdaddy53 said:


> I doubt the linkage moved, to physically adjust the linkage it has to be unclipped and screwed in or out to make it longer or shorter. Stranger things have happened but I think it’s a mechanical issue in the gearcase.


Agree. The only thing I can think of that may be causing an issue linkage wise as a piece of trash or corrosion stopping it from going all the way into reverse but it is very unlikely.


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## Frank Ucci (Jan 20, 2019)

1) Remove prop
2) Remove engine cowling
2)Disconnect shift cable from motor
3) Connect flushing attachment to motor
4) Turn on water
5) Start motor
6) Attempt to shift motor into reverse using motor's shift lever

If it shifts into reverse properly, you have a problem with your cable or your shift box. If it doesn't, you have something wrong with the motor's lower unit shift rod or gear case.


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## efi2712micro (Sep 17, 2015)

Well … doing the deep cleanup back at the house this morning, put the ears on the engine and idling or in neutral revving up, I can clearly hear a mechanical clang in the lower unit. Revving up made the noise louder so shut it down.


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## efi2712micro (Sep 17, 2015)

And today, walking in the garage …. Grease mixed up with water I assume! Coming off between the prop and the lower unit housing. Thoughts? It’s going to the shop tomorrow


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## Smackdaddy53 (Dec 31, 2012)

Compromised shaft seal allowed water in and gearcase lube plus water doesn’t protect gears and bearings from friction very well. You might have caught it early. 
pull the plug and see if there are big fragments of metal or wait for the mechanic to.


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