Trouble engaging reverse

[FreoDreamtime]

Engine - Volvo Penta MD2040
Gearbox - Volvo Penta MS15L-A
Gear shift - simple forward /aft shift with vertical neutral position and red button to achieve higher RPM in neutral, mounted on starboard side of binnacle.
Prop - Kiwi Feathering

Issue - forward engages without fault from neutral. Reverse from neutral position results in the engine appearing to overload, no reverse thrust / drive.
I have checked forward and reverse at gearbox end, the lever at gearbox end appears to rotate the shaft that enters the gearbox meaning it appears to be rotating fully forward for reverse and fully backwards for forward gear. Note I did this test while engine was not running.
I have checked ATF and level is fine which I would expect as engine had major service in October 2021.
A solution I stumbled on is to start engine, move into forward so forward gear engages then immediately shift into reverse and every time reverse engages normally.
Our diesel mechanics here are running with a two-month lead time to get to your boat, even as a registered customer they are that busy.
This weekend I will take a look at gear lever and mechanism on binnacle end but as this appears to be fully moving the lever on the gearbox I am not too hopeful, added to this the reverse is engaging when I shift from forward straight into reverse.

I'll also take look on the weekend with a mask and snorkel and check the feathering prop position and ensure it is clean and able to feather and deploy freely as I read on another thread here that this could be an issue with feathering props (noting I am engaging reverse fine from forward so I am doubtful).

Any insights greatly appreciated.

[Tia Bu]

Sounds like a new or rebuilt transmission will soon be needed. Hope I'm wrong. Approach all docks as if you have no reverse. Sooner or later, that will probably be the case...

[FreoDreamtime]

I have been coming into our downwind pen / dock real slow and lines are stowed neatly at departure for easy retrieval on approach as they should anyway. So far so good and the short shift forward and straight to reverse has worked but its not my favorite way of ending a few days away.

[Rumrace]

Reverse is suppose to work but not forward on a blown clutch but it still sounds like a bad clutch. If it’s a cone or disc clutch some can be resurfaced. If it’s a dog clutch it can damage the transmission.
Also there is a cut out switch which suspends power from the engine for a second to take the torque off the shift on clutch and engaging gears. Stretched cables, cables needing lube, adjustments to throttle can make this switch only work for shifting into forward but not reverse.
Most are a micro switch on most motors mounted where the cables enter the engine room or on the top of an out board.
Assure it’s working by starting the motor then cut it out by pressing the arm. The two screws will allow you to adjust it to suit cable changes.

[FPNC]

The MS15A is a ZF 15MA and Volvo labeled, multi disc transmission. Check your linkage throw. It must move all the way to where the lever releases. Or the clutches will slip. It can be replaced with a new ZF 15MA or a TMC 60A. Note that the prop flange will need to be replaced as well.

[AnsleyS]

Free,


I think that you are just having difficulty with the feathering prop popping out when going into reverse. This is common with some types of feathering props. You are doing it properly by putting her in forward and then shifting into reverse. That helps to shake the prop loose.

[FreoDreamtime]

Thanks for all the advice, it’s weekend so we’re aboard and time to test some of the ideas. Morning coffee first though