4HP Reverse Gearshift Problem

Hi, I have a 2000 4 stroke 4HP that no longer can go into reverse. We think that the problem is with the shift linkage as forward works fine. Neutral works but is sloppy now and reverse simply cannot engage anymore. A fast ticking/clicking sound is made as it tries to go into reverse. The reverse gear does not engage and neutral doesn't seem as firm anymore.

If you push down the gear linkage in the leg manually the prop locks into reverse gear, but once you let go, it pops back out.

Is this a common problem, and do any experts have any solutions, or does the whole powerhead need to be dismantled to get to the internal gear linkage?

[boats.net]

Remove rubber plug on side of upper housing and check shift shaft clamp may be loose.

Hi, thanks for the quick reply! We tried that initially and the clamp was tight and not slipping. We tried to reposition the lock point to adjust the play anyways but could not get the right position.

Can the upper shift rod bend above the shift shaft clamp which would reduce the amount of travel/throw of the dogs/gear - or is this unlikely? I understand that some rods that are not stainless do rust/bend over time causing this type of problem.

Since the lock point was tight, it appears there is some additional unaccounted for, travel loss somewhere along the linkage between the hand lever and gear.

[EDIT: The engine is used in salt water, and the internal and external anodes have been replaced as necessary - corrosion does not appear to be a problem, but interestingly there looks like some paint bubbling on the upper leg above the rubber plug]

Yours truly

[boats.net]

The loose play could be from shift linkage or it could inside gearcase. I haven't seen any of those shift shafts rust in too but it's possible.

Thanks for the quick reply! We're going to have to look at the linkage closer to find out why there is play now, and not before. It seems to be a straightforward solid rod mechanism between hand lever to shift shaft clamp so it's perplexing as there isn't a lot of bending stress on the rod as gears are changed.

Possibly the gearcase mechanism does have something to do with the problem.

Yours truly

Update - it appears the shift linkage between the gearshift lever and the upper shift rod is the likely culprit so the powerhead has to come off to replace.

Thanks for the suggestions boats.net

Yours truly

Final update - the problem was the upper shift rod, it rusted to a point where it thinned and was flexing when put into reverse.