Lower Unit - No Reverse

[dave621]

I've been working on this engine (1990 XR4) for quite some time now and have the old girl put back together but have run into a problem getting it into reverse. When I drop the lower unit and manually move the shift spline from Forward to Neutral all goes well but when I go past Neutral (spinning the prop) to where Reverse should be it goes into Forward again. So what I got is F - N - F instead of F - N - R. I have a feeling the problem is related to the clutch dog. The lower unit was rebuilt and it did have reverse, but I think something is out of whack now.

Question is can this be fixed without doing a complete tear down?

 

[nbnewbie]

Re: Lower Unit - No Reverse

are you continuing to turn the shift shaft in the same direction or going both directions from N

 

[dave621]

Re: Lower Unit - No Reverse

I'm moving in both directions and it always goes into forward when leaving neutral.

 

[dave621]

Re: Lower Unit - No Reverse

Also, when I put the lower unit back on in Neutral the splines line up to far forward which causes it not to fully engage into forward when shifted. If I put the lower unit on in Forward and line up the splines where it fits when I put it Neutral it's still in forward until I pull it back into reverse then it goes into neutral. It's like there is to much play in the shift spline on the lower unit which is what leads me to believe there's something wrong inside the lower unit.

 

[nbnewbie]

Re: Lower Unit - No Reverse

there are 2 types of shifters for those lower units the one you have which will turn 360 and one that won't on the ones that will turn 360 N is a detent position hardly noticeable and the shifter will turn past it back to the forward gear position if rotated too far the only way i've been able to get that one working properly is to manually turn the prop or prop shaft while very carefully turning the shift shaft to find reverse then leave it in reverse and position your shift throttle control lever as far to reverse as possible (important just till the throttle cable starts to move) then install the lower unit with it in reverse this has always worked for me with this lu i've never been able to consistently install it in the N position hope it helps you

 

[dave621]

Re: Lower Unit - No Reverse

Thanks, I'll give it a try tonight. I know one thing I'm good at taking the lower unit off and on now. Gesh this thing is going to drive me nuts

 

[dave621]

Re: Lower Unit - No Reverse

I've tried turning the shift shaft till I was blue in the face. Spinning the prop while moving the shift shaft Clockwise and Counter Clockwise coming out of Neutral. I always get F - N - F. Not sure what to do now but I'm leaning toward tearing it apart and check the clutch dog. I have the shop manual for the motor it's either me tear it down and fix or buy a new lower unit from eBay. I know shop will rip me a new one to tear it down.

If you can think of anything else I would love to hear other options.

 

[nbnewbie]

Re: Lower Unit - No Reverse

sorry that didn't help next i would check the shift cam at the bottom of the shift lever for wear or broken a bit difficult to get at but easier than clutch rebuild

good luck

 

[Chris1956]

Re: Lower Unit - No Reverse

Dave, When that motor shifts from F-N-F, it could be bypassing Reverse. If so, it is really shifting F-N-N-F, where R would be between the two Ns.

Reverse is where the shift cam pushes the most against the spring inside the gearcase. Maybe the reverse cam is worn/broken? I have never seen this, but have little experience in this area.

 

[dave621]

Re: Lower Unit - No Reverse

Hi Chris, I think you got it right. When shifting out of Neutral halfway between Forward and Neutral there is a sticky spot when turning the shift shaft that feels like it should be a gear but it just slides right past it when turning the shift shaft.

I'm thinking that I'll will be tearing this thing down to find out what's wrong ugh

Thanks for all the reply's and ideas guys this is one of the most valuable boating sites on the web.

 

[Wingedwheel]

Re: Lower Unit - No Reverse

Did this problem happen before or after you removed the lower unit. Perhaps its turned past the gear and your using the back-side of the shift-cam instead of the front. Does that make sense?

 

[dave621]

Re: Lower Unit - No Reverse

It happened before I removed the lower unit, I replaced the throttle cable and unhooked the shift cable when putting in the throttle cable. The next time I took the boat out I had no reverse so I dropped the lower unit to check it out and haven't been able to get it back. When the lower unit was rebuilt the mechanic was having a hard time getting it back on so I don't know if I'm missing something but I have messed with the shift shaft turning it CCW and CW trying to find reverse and I come up with nothing but F - N - F.

If it is turned past is there a way to get it back to using the front side of the shift cam again?

 

[Chris1956]

Re: Lower Unit - No Reverse

I would think the shift cam would turn all the way around. If not, try both ways, firm but not too firm, and see what happens.

 

[dave621]

Re: Lower Unit - No Reverse

Thanks guys for all the help, hopefully I figure this thing out soon. What I get when I turn the shift shaft is it hits a stiff position which within the stiff position there is a detent position which puts it into Neutral then when I turn it out of the detent CW or CCW it goes to forward then the shift shaft freely spins 360 degrees till it comes to the stiff section which puts it back to Neutral.

What I don't get is why the shift dog always heads back to the forward gear when shifting. The dang thing should just go back and forth between the forward and reverse gear right?

I have a feeling I have a winter project on my hands when I can tear the dang thing apart. I get it this old girl back together and she might find herself on the classifieds section this time.

 

[Chris1956]

Re: Lower Unit - No Reverse

Dave, I am not that familar with gearcases that new, I am sorry to say. The Alpha I I/O gearcases do not have a good detent into neutral, and slip into forward easily. My old Merc has a solid detent to hold neutral.

 

[Wingedwheel]

Re: Lower Unit - No Reverse

Dave, from what your telling us. I believe the 'stiff' spot is actually your reverse. Whats happening is its not actuating it all the way. The way it works is your forward is spring assisted and the reverse gear is spring opposed, meaning you have to push against a load to go into reverse. It sounds like something is stuck or broken/worn. Perhaps it was time for it to go, perhaps the mechanic who rebuilt it could have put the shift cam on upside down? This sounds like something that will have to be visually inspected. The lower units are fairly simple once you get the carrier out. If it was rebuilt not long ago it should come out easier than if it was never taken apart.