Yamaha 4hp Gears difficult to engage

[nyx]

i have a 1994 single cylinder 4hp 2stroke Yamaha

its been perfect but today i had to try many times to engage either gear.

it can't be forced into gear by using excessive pressure on the lever but if i give the prop a wiggle it engages fine with fwd and rev gears.

any one know how to diagnose the problem and fix it.

kind regards Nick

 

[lw395]

The gearbox will only engage when the shafts are at certain angles to each other. When the motor is running, it soon finds a point where it will engage. When stopped, the prop may need to turn relative to the engine. Otherwise the drive dogs will not intermesh.

 

[nyx]

the problem is encountered with the engine running

 

[Ramage]

Have you checked the gearbox oil?

 

[Cliveshep]

Sounds like the selecter wedge may have burrs on it or the rod down the leg is jamming or linkage under the cowling. You need to check the linkage first before stripping the lower unit and checking that the dog clutch mechanism is free to move.

 

[nyx]

thanks for the advice. I'll look at the rod and wedge on the back before i take the whole leg apart

 

[Ubergeekian]

[ QUOTE ]
i have a 1994 single cylinder 4hp 2stroke Yamaha

its been perfect but today i had to try many times to engage either gear.

it can't be forced into gear by using excessive pressure on the lever but if i give the prop a wiggle it engages fine with fwd and rev gears.

any one know how to diagnose the problem and fix it.

[/ QUOTE ]
You probably have to open up the gearbox to check. It's quite easy: prop off, undo the two bolts on the flange and pull it out. You'll probably find a dearth of oil and lot of crap in there.