1984 35hp Mercury, won't go in reverse

[HTG]

This engine will go in reverse on land with the hose and works fine. For some reason, I can't get it to go in reverse when its in the water. And I'm having some difficulty getting the throttle to go in reverse when its in water. When it does it just revs up but won't engage. Anyone know how to fix this? Or Is this a major overhaul or something simple?

 

[HTG]

Anyone dealt with this problem? Will the lower unit have to be removed to fix this?

 

[racerone]

Provide more information.-----Was lower unit off for pump work ?----New to you motor?----It is not fully shifting on the trailer ! Lower unit might have to be removed to line up shift shafts properly.----I am not there to see the simple issue.----Provide information.

 

[HTG]

I haven't removed the lower unit for a few years so that didn't do it. I took it off to replace the impeller and it ran fine for three seasons after. It started about a year ago. I ran it through last summer, it doesn't effect forward. It will fully function on the trailer with the hose, however it won't engage in water and I can't really put it in reverse without it grinding when its in the water.

I'm just wondering if I do remove the lower unit what needs to be done? Or is there anything else I can check before removing the lower unit? I have removed the lower unit once and and it took awhile. Are there any videos on how to fix this? I checked youtube and couldn't find anything. I don't know where to start and I don't have any leads yet.

 

[racerone]

Tried adjusting the trunnion ( anchor point ) on the cable ?----I think there is a tutorial somewhere on this Mercury forum that will tell you what to do here.----Just look about 2 posts above your on the Mercury forum.----" Simple method of shift shaft set-up "

 

[HTG]

I think I found it? Is it the tutorial below?
"This is how I do it in about 60 sec.: Turn the LU shift shaft by hand counter-clockwise until it
stops, then with Vise Grips tight on the bottom of the shaft turn it a
few more degrees CCW until it clicks into a stop, this
should be neutral - check by turning propshaft --
prop should spin freely.
Put control in N and go ahead and attach LU to driveshaft housing some turning of the flywheel will help the DS splines align.
Do not shift into reverse unless you turn the prop at the same time."

Are these the two cables that enter the engine from the shift box? What is the LU shift shaft? Thank you I'll try that.

 

[HTG]

I still can't find the problem. Just wondering if anyone may have any other ideas?

 

[HTG]

ttt

 

[Roadking57]

Sounds like a shift cable adjustment problem. check both ends of the cables and any spots where the cable runs thru or right next to anything. Make sure the cable outer jacket is not worn thru where the cable could bulge up thru. Esp where you cant see it. If all thats in good shape you may have worn gears or a shifter fork might have one side broken off not allowing it to fully engage. disconnect the cable and try shifting it back and fourth by hand (NOT RUNNING). listen and feel for anything not normal. Maybe put ear down next to foot while a helper flips shifter back n fourth. Should hear and feel positive clunks.
GL
RK

 

[HTG]

Thanks for the info, I checked the cables and can't find anything out of the ordinary. I might double check.