Mariner 30hp 1992 gearbox jumping

[papajoe]

Hi all, I'm at the end of my tether with a silly problem (ebay engine). I've got a nice clean yam made mariner (689 series) anyway, the original problem was it was jumping out of forward gear on minimal power, so I reset the remotes and tried again. Better but still jumping out of forward gear. More research and I thought it could be the clutch dog so stripped the gearbox and the clutch and gear had a slight rounding off the lead edge, I took it to the guys at ribs marine who said it didn't need replacing. So rebuild the gearbox and tested and all seems ok. Well, tried it tonight and same problem is there. I have increase the length of the gear shifter linkage (2 part) to the maximum I can get away with. The problem is better but its still jumping out of gear on throttle up and I have no more adjustment left. What am I missing? One thing I can't remember seeing though is the slide spring (no.37) when I did the strip out and rebuild.
30A Mariner Outboard 689-105325 THRU 689-530100 (ML) GEARHOUSING Diagram and Parts

cheers Joe

[papajoe]

I've been looking at the parts list and if I remember the clutch dog is/was on back to front with the f marking facing the reverse gear. Are the gears cut differently?

[beamishken]

I'm no expert but from the sound of things it's possible someone swapped the clutch dog over to get a bit more life out of it as reverse rarely fails
Sometimes difficult to see with the eye wear on gears & they can look ok but actually worn enough to jump out
Obviously if there is a spring missing then that could be your problem

[Davie]

#37 is only in some engines. First check the spring pushes the clutch dog cross pin fully home to the end of the slot in the propshaft. If it doesn't I would suggest somebody has lost #37.
Making the shift shaft longer will make it jump out of forward gear you want to be shortening it to lift the shifter higher letting it further into forward gear.

[papajoe]

Cheers Davie, more work me thinks

[9D280]

Fwiw I had the same problem with a 72 vintage Johnson.

Cured with a new(er!) Dog & gears.

[phantom 19]

Joe I probably have a complete long shaft gearbox spare, definatly got at least two short shaft boxes spare if not more.

[papajoe]

hmmmm, whats the damage?

[papajoe]

Originally Posted by 9D280

Fwiw I had the same problem with a 72 vintage Johnson.

Cured with a new(er!) Dog & gears.

Thats the back up plan if I can't sort a spare unit

[papajoe]

Good news, stripped the box beside the river today, swapped the dog around and bingo, problem sorted. Going to do some higher speed trials mo

[Nightfisher]

Set drive cables if equipped, for being in spec, meaning measurements under the cowl.

[papajoe]

all fixed now thanks nightfisher, pretty pleased with the performance so far, had her up to 26knots with a bit of chop.
New prop next!