Volvo Penta Gearbox MS3C

[Fullabeer]

Hi All,

I've got a problem with my port gearbox. It was working fine, and still goes into reverse fine, but when shifting to forward it just slowly rotates and then stops after a minute or so.

So couple of questions if I can:

• Has anyone had this issue and if so, what was the cause?
• Does anyone have suggestions on what to check for? I've checked oil and levels are fine and isnt too black
• Any recommendations of someone that can overhaul it?

In case it's relevant, the gearbox is coupled to a TAMD31B.

Many thanks in advance

 

[VicS]

Have you checked that the external lever is moving fully ?
Cable adjustment ??
Tried disconnecting the cable and operating the external lever by hand ?

 

[superheat6k]

I overhauled my MS3B a few years ago and could not find a manual - so I wrote one. I expect your box might be similar.

Good luck.

 

[oldgit]

Many new parts are still available from VP. Second hand bits and complete gearboxes do turn up on ebay .
Your problem may be finding somebody local prepared to look at it.
It is a simple very basic gearbox and if the problem is internal after removal and dismantling any failures should obvious.
The box is small and light enough for a keen individual to remove .
Will need sufficient room to slide box aft to from engine shaft splines.
With luck this only involves releasing prop shaft from flange/ flexible joint and pushing prop shaft back a few inches.
Take real care removing water cooling pipes in order not to make extra work.
Later box but same principle.

 

[Fullabeer]

Have you checked that the external lever is moving fully ?
Cable adjustment ??
Tried disconnecting the cable and operating the external lever by hand ?

Yes, checked that first and sadly that isn’t the issue

 

[Fullabeer]

I overhauled my MS3B a few years ago and could not find a manual - so I wrote one. I expect your box might be similar.

Good luck.

Thanks mate, I actually downloaded this from somewhere already. It’s great, but I also need help with diagnosis as I wouldn’t know what to look for

 

[Fullabeer]

Many new parts are still available from VP. Second hand bits and complete gearboxes do turn up on ebay .
Your problem may be finding somebody local prepared to look at it.
It is a simple very basic gearbox and if the problem is internal after removal and dismantling any failures should obvious.
The box is small and light enough for a keen individual to remove .
Will need sufficient room to slide box aft to from engine shaft splines.
With luck this only involves releasing prop shaft from flange/ flexible joint and pushing prop shaft back a few inches.
Take real care removing water cooling pipes in order not to make extra work.
Later box but same principle.

Thanks. Was hoping to hear a company I can just send it to. I can remove it, just rather have someone that knows how to recondition it.

 

[oldgit]

Volvo Paul of this parish might be your first port of call. Depending on where you live but it might be case of sticking it on pallet or delivering.
Try ringing anybody local who mends marine gearboxes but most only seem to want to get involved with hydraulic stuff.
Think there are a couple of pucker VP dealerships (Volspec etc ) in Essex who might take a look at the box but suspect they will do the job "properly" and with a proper VP price to match.
CoastRides in Dover were trying to unload a large pile of MS3 parts recently online, suspect that the bits being got rid of are the bits that do not fail unfortunately.

One word of caution. One now disappeared forumite bought a boat with a iffy gearbox, it had worn cones. Was assured that they could be "reground" by some expert ,to make them do their job again. It did not work The gearbox was in and out like a yoyo.
Owner eventually got fed up and fitted a new gear box which involved a lot of time, money and faffing. Shortly after he gave up boating and sold the boat.

 

[Fullabeer]

Just wanted to give an update to anyone else that has this issue....I've fixed it!!

In short, the brass selector cone was worn and rather than trying to regrind it, I replaced it along with the selector. This little brass part is almost £900!! If you can get someone to engineer it, great, but otherwise it's an expensive job.....which it was.

Gearbox is like new and slips in and out like a dream! First few projects on the princess are done. Next job is to find a good upholsterer in Essex.

 

[superheat6k]

Nice to hear you fixed your problem. Not unusual to hear VP charging rip off prices for basic components.

I will be very pleased never to own a boat again with VP engines.

 

[oldgit]

The MS3/4 boxes are supposed to give a nice solid "clonk" when engaging.
These boxes have a less than stellar reputation, on the other hand there must have been tens/hundreds of thousands of the things installed over a decade or two, some will be now 50 years old with thousands of hours under their belt. Most of them still chugging away ...........So a few have worn out or fail !
You can still get many parts to this day from Volvo and all within 48 hours.
A pretty impressive record really.
Trying getting a part for any other 50 year old boat bit.

 

[Mirage Aft]

I overhauled my MS3B a few years ago and could not find a manual - so I wrote one. I expect your box might be similar.

Good luck.

Very good instructions! I am just about to strip down my MS3B. Regarding undoing the top nut, you mention holding the bottom of the shaft with a 21mm socket. The shaft is splined, 17 of them. Did you use a regular socket to hold against the significant pressure required to undo / tighten this nut? I was also thinking that it might be better to undo the nut before removing the box but not sure if the engine will give enough resistance? Would really appreciate you thoughts on both points. Thanks, Alan