bpp
New member
Transmission pops in and out of forward gear at low throttle setting. 2500 hrs oil level good
volvo penta ms4a transmission
- Thread starter bpp
- Start date
volvopaul
Well-known member
Possibly worn cone clutch .
bpp
New member
Looking at buying boat with this problem. Consider myself a good mechanic but not familure with marine transmissions. Is this part available and is it replaceable without special tools?
volvopaul
Well-known member
Yes and no , more knowledge on how to strip and set up .
bpp
New member
Thanks, I'll see if I can find a shop manual.
oldgit
Well-known member
Any search on the interweb should produce an exploded diagram of MS series gearboxes.
Two points of view on this gearbox and before deciding on a course of action worth remembering that this reverse gear has been around since the dawn of time and probably tens of thousands are still out there doing stirling service in thousands of boats.
The fact is that very few actually fail, prop strikes mainly , majority certain bits simply wear out.
The diagrams will show a very simple piece of kit and Volvo Penta still do make some parts.
Box can be physically removed by a single keen & fit tightwad DIYer in an hour or two, no need for expensive yard based boat ashore job or Hi Ab etc to get unit out of boat.
Simple to remove, however finding somebody to diagnose the fault is where the problems start to arrive.
Most marine gearbox menders only appear to want to repair hydraulic boxes, this may well be because parts are commonly available and probably a profit still to be made, suspect that repair shops have spent time pulling apart too many MS boxes , wasting time and money , to find the owner reluctant to cough up for an unrepairable gearbox all in bits.
A couple of things to consider, secondhand units are rarer than sunny summer days ( it will need to be the same ratio) and any replacement new gearbox involves moving engines and extra plumbing.
VolvoPauls diagnoses is probably spot on .................as always
Reverse Gear MS4B (872210)
Two points of view on this gearbox and before deciding on a course of action worth remembering that this reverse gear has been around since the dawn of time and probably tens of thousands are still out there doing stirling service in thousands of boats.
The fact is that very few actually fail, prop strikes mainly , majority certain bits simply wear out.
The diagrams will show a very simple piece of kit and Volvo Penta still do make some parts.
Box can be physically removed by a single keen & fit tightwad DIYer in an hour or two, no need for expensive yard based boat ashore job or Hi Ab etc to get unit out of boat.
Simple to remove, however finding somebody to diagnose the fault is where the problems start to arrive.
Most marine gearbox menders only appear to want to repair hydraulic boxes, this may well be because parts are commonly available and probably a profit still to be made, suspect that repair shops have spent time pulling apart too many MS boxes , wasting time and money , to find the owner reluctant to cough up for an unrepairable gearbox all in bits.
A couple of things to consider, secondhand units are rarer than sunny summer days ( it will need to be the same ratio) and any replacement new gearbox involves moving engines and extra plumbing.
VolvoPauls diagnoses is probably spot on .................as always
Reverse Gear MS4B (872210)
volvopaul
Well-known member
He can send it to me.Any search on the interweb should produce an exploded diagram of MS series gearboxes.
Two points of view on this gearbox and before deciding on a course of action worth remembering that this reverse gear has been around since the dawn of time and probably tens of thousands are still out there doing stirling service in thousands of boats.
The fact is that very few actually fail, prop strikes mainly , majority certain bits simply wear out.
The diagrams will show a very simple piece of kit and Volvo Penta still do make some parts.
Box can be physically removed by a single keen & fit tightwad DIYer in an hour or two, no need for expensive yard based boat ashore job or Hi Ab etc to get unit out of boat.
Simple to remove, however finding somebody to diagnose the fault is where the problems start to arrive.
Most marine gearbox menders only appear to want to repair hydraulic boxes, this may well be because parts are commonly available and probably a profit still to be made, suspect that repair shops have spent time pulling apart too many MS boxes , wasting time and money , to find the owner reluctant to cough up for an unrepairable gearbox all in bits.
A couple of things to consider, secondhand units are rarer than sunny summer days ( it will need to be the same ratio) and any replacement new gearbox involves moving engines and extra plumbing.
VolvoPauls diagnoses is probably spot on .................as always
Reverse Gear MS4B (872210)
oldgit
Well-known member
Shaft failure due to prop strikes ?
Both had whacked something sometime in the past, in one case several months.
Both had whacked something sometime in the past, in one case several months.