DF25 Won't Lock into Reverse

[gogittum]

I recently purchased a 2008 DF25 V-twin that the seller told me had an issue with shifting out of reverse. I looked it over and found that it would shift into F and back to N just fine, but shift to R and it woiuld lock into R and be impossible to get back to N. I'm a lifetime mechanic with a lot of experience in such things and felt it would likely be a linkage problem or similar, so bought it.

Well, it's turned out to be not so simple. I've had the lower unit gears apart several times now and replaced the gouged shift cam with no joy. "Very" carefully checked components against the exploded view in the service manual and all are there and in the correct positions.

I should mention, too, that he gave me a box of odds & ends that I just glanced at. When I got home, looked them over and found a shift lever (this is a tiller motor) that's badly scraped on 2 sides - not parallel or inline. Looks like it was dropped and dragged across very coarse concrete - but there is no other damage to the motor - not even a scratch on the paint. Can't figure out how someone managed that.

With the motor in F, the prop will turn freely a few degrees back and forth before taking up the slack in the dog clutch, then locks solidly into F and you can turn the motor over with the prop.

Put it in N and it spins free and clear. Now put it in R and turn the prop and it turns a few degrees back & forth, just as in F, but then if you put pressure on it, you can....uh....pop it ?? over a resistance for a few degrees before it pops back to free turning. It wont turn the motor over - it slips. When it's in "free turn" mode, it shifts out of R just fine. When it's on the resistance, the gearshift is locked solidly and can't be moved.

It appears that the dog clutch isn't pushing all the way into mesh with the R gear and under pressure it cams itself up and over the clutch faces and this puts huge pressure on the push rod and shift cam, thereby causing the divot on the shift cam.

Disconnect the upper and lower shift rods, shift into R and it makes no difference. The divot on the shift cam is in the proper place to show that it's going all the way down into what should be R....but the gear and clutch don't match that. Shift detents for all 3 positions seem to be fine. Linkage isn't an issue - this is all inside the gear case.

Pushrod doesn't appear damaged. All components are in place. None are missing or doubled up. How can it shift fine into N & F, but not into R ?? Yes, it appears that the motor was dropped and/or dragged very hard on the shift lever but how could that affect R inside the gear case ??

[gogittum]

A couple of further thoughts: I tipped the motor up and pulled the propeller shaft and reverse gear out without removing the oil. Then reached down into it with a long, clean screwdriver to:

(1) - see if the shift cam was solid in its' track. If track was broken by being dropped, it could let the shift cam tilt sideways and jam. Nope - tight and solid and smooth. No side play at all.

(2) - make sure the shift cam really is being positioned properly to engage R. Yes, bracing the screwdriver against the housing and moving the shift lever from F thru N to R had all 3 positions clearly and solidly in place. The divot on the R face from the pressure of the dog clutch riding over the R gear engagement is in the proper place. (if the R step was 1/4" higher, my problem would be solved.....but not the underlying cause)

OK, it "almost" goes into R and does go solidly and cleanly into N and F. I really Want it to go solidly into F for obvious reasons. R isn't so critical - it's not a high stress component in comparison.....but I do need some engagement.

If I were to pull the washer out of the R/dog clutch meeting face, it would give me about <1/16" more engagement. Would that be enuf ?? I doubt it, but it could possibly give a useable R. BUT - not good to 2nd guess mfr about such things - those are all precision components. Maybe cause high wear levels in that area ??

I could put a 1/8" spacer between the shift push rod and the push pin over the spring and that would give some engagement - but at what cost to the F engagement ?? and N dis-engagement ??.....and again, 2nd guessing the mfr on very critical (and expensive) components. I don't really want to go there.

The mark on the dog clutch is facing forward as per specifications.

[gogittum]

Found it. I was contemplating a shim between the push rod and the push pin that would push the dog clutch farther back to engage the R dogs, but unsure of how that would affect F gear engagement. Looked at the parts breakdown one more time and saw what looked like a hole thru the push pin. Hmmm.....??? If the previous owner had it apart (he did) and put the keeper pin "over" the push pin instead of thru it, that would rob R of 1/4" of travel - all I'd need. I'd already seen where he'd mis-assembled the upper shift handle, sooo....??

0N6936.JPG

I pulled it apart yet one more time and pulled the dog clutch locking pin......and it was broken - from the impact when the motor was dropped. I believe it worked OK going into F under the light pressure, but when going all the way against the spring into R, it folded into a V shapel and didn't push the dog clutch all the way into R. It broke in half - no loose pieces to tangle in the gears.

I found a hardened pin at a parts house and installed it this afternoon. The shifter still sticks in R slightly, but I believe that's due to the push rod hanging up in the divot on the cam from the heavy pressure. It should smooth out quickly.

[gogittum]

I'm not doing something right here or not seeing something, but I tried to start a new thread on this and couldn't make it go. Gave up on it. For me, at least, this site is Not user friendly.

When I re-assembled it with the new pin in there, it Still wouldn't go all the way into reverse and was still stiff to shift out of R - same problem. Start over.......

OK, instead of going all the way into R, the top edges of the clutch dog and R gear dog would hit, then ride up over each other and put a huge camming force on the components from the shift cam all the way to the broken pin. Instead of being square edged like the F side, the faces of the cam lugs on the R side are now slightly radiused - about 0.01" or 0.02" or so.

This force created a large divot in the new shift cam at the R position and it smashed the ends of the shift push rod flat. Not sure of the effect on the push pin that the push rod pushes against, but certainly didn't do it any good.

Altogether, the damage equals about 1/10 inch. Not good, but not enuf to cure my problems either. On Friday, I did order all new parts in that sequence, just to be sure, but I think there's something else wrong in there that I'm missing.

Also, when I opened it up the 2nd to last time - for the 3rd time - I'd run it for several miles in the river and all was fine. When I opened it up this last time, the gear lube was an ugly greenish yellow pus color - water in the oil. Bought fresh lube and ordered a complete set of gear case seals.

Migawd, I just want to go out and play on my boat. This is like some kind of evil gremlin sitting on my shoulder, gumming things up.

[Murray]

For new post you have to be on page 1. Just above the Sticky’s there is a small baby blue box with “+New Topic”

[gogittum]

For new post you have to be on page 1. Just above the Sticky’s there is a small baby blue box with “+New Topic”

Thanks. I clicked all over the place, looking for stickies and finally found them and the New Post box under Suziuki Outboard Parts Forum. Guess it'll take some getting used to.