[javiert99]

I have an older mid 80's Yamaha 175 that is being pretty strange about going into reverse. It is a 175AETO, but I believe it is the equivalent of an 175ETXK (175hp 20" shaft)

When cold, or after idling for a while, it won't go into reverse, it just grinds. If you take the cable off, it will pop itself out of gear. This is the same whether on land with the muffs on, or on the water. If you adjust the throttle cable back far enough you can hold it in reverse on the muffs. On the water with the cable on it will just grind though when cold, or after a while of idling, etc.

I found today though that after running around at a decent amount of speed, some full throttle operation and some part throttle (3k rpm or so) runs it will shift into reverse just fine afterwards.. It won't grind or complain, it just "clunks" as it does into forward and it works just fine. My throttle doesn't appear to be adjusted right as it doesn't give me much room to give it much gas, but at least it engages. After it "cools off" and you go back to idling again for a while, it will no longer engage.

Forward works fine, all the time, every time.

I changed my lower unit fluid and saw some metal on the magnet, and the fluid didn't look too great, but I saw no chunks or anything along those lines.

Can someone make some sense out of this for me? The shift shaft on the motor seems fine. It's a solid 1/4" wide, does not appear to be corroded based on the two sections I can see, not sure if it could be corroded in other areas or if this would even be related.

I just bought the boat knowing reverse was a problem (the price reflected it) but I'm trying to get an idea of where I need to go w/ it.

Thanks!

[javiert99]

The more I read the more it sounds like the shift shaft, even though the two locations that are "visible" with the motor assembled (especially right above the cavitation plate) seem to be solid. Does the fact that the engine will engage reverse after some time at speed clear the lower unit of fault? Why would it engage sometimes and not others?

If I pull the lower unit and the shift shaft looks OK, should I assume it's ok in other places I cannot see it?

If the shift shaft is bad, is the stainless part standard across a certain number of years and motor series?

I have this "175AETO" and I'm not sure how to order parts for it when the time comes. It's a 20" shaft mid 80's Yamaha is all I really know.

[javiert99]

Well, I got no replies, dunno why... but I just wanted to report back that after quite a bit of searching and speaking to others I came to the conclusion that my lower unit was bad.

I found a parts motor with a blown powerhead but good lower unit for a great price and swapped my old lower unit with this one. Now I have reverse working 100% of the time, and my shift shaft looks like it should give me years of service based upon inspection.

All is well once again in the land of my Yamaha.