Volvo MD22L

[Sppro]

A friend (whos in open seas right now) has a Volvo Penta (or Perkins) MD22L engine where the propella is not spinning.

There is an impeller which runs seawater to the heat exchange, its not turning.. They would like to know if there is a clutch attached to the impreller and how to access it? The imprella is ok but not spinning when motor turns, all belts are ok.

Any ideas would help.

[Wotname]

There isn't a clutch on a seawater pump impeller. If it isn't turning when the pump shaft is turning, then the impeller needs replacing.

Pretty easy job assuming your friend has a spare impeller on board.

[Sppro]

Thanks for your response.

My friend says the shaft isnt turning either.,

[jimbunyard]

If your friend has an MD22L-A or earlier, the water pump">raw water pump should be driven by the camshaft (as far as I can tell), via a coupling that looks like this




https://www.parts4engines.com/perkin...rive-coupling/

This part is not shown in either the Volvo or Perkins Prima factory parts catalogs that I could see; the only p/n I could find was 163081. I could not tell from the picture if it is metal or plastic; if the drive tang is broken, this seems to be the only 'clutch' that could cause the pump shaft not to turn, short of the drive tangs on the shaft being broken. To access it to determine if this is the problem, the r/w pump will have to be removed.

If the engine is an MD22L-B, the R/W pump drive should be a Poly-V belt and any problems there should be obvious.


Perhaps later today someone with more direct knowledge of this particular engine will weigh in.

[Wotname]

Originally Posted by Sppro

Thanks for your response.

My friend says the shaft isnt turning either.,

Would that be the propella (propeller) shaft (that is, the thing that moves the boat) or the impeller shaft inside the seawater pump?

[Mikmet]

Here are some diagrams
https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744150-26-308.aspx

https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744150-26-309.aspx

[Sppro]

thanks for everyone responses. I'm the proxy in the middle with my friend and I have 0 mechanical knowledge. We are talking about the impeller shaft.

Responses from my friend (to avoid my stuffing it up im just writing it word for word so it spans a bit of time, any assistance for me to forward on would be great):

We got the pump off and we can see the coupling. There is alot of hard greasy gunk in there which we cleaned out but we noticed a spring in the pump. Is that meant to push the coupling together? we cant seem to budge it at all, if there is supposed to be some play can someone please confirm the same?

It's not a spring actually, its an 0 ring. looks like it slipped out and there is some wear damage in the coupling but hopefully we can get it working.

are we supposed to grease the coupling?

There seems to be a fair bit of play, is there anyway to adjust the clearance of the coupling

[Mikmet]

The way I see it from the diagrams, the complete sea water pump assembly (not under the impeller cover - the whole pump) has a shaft in it, and is rigidly mounted in the pump housing with bearings. It should spin but not move in and out..
The front of the shaft has the impeller.
The back of the shaft has a slot in it that drives it.

In between, on the shaft is a gap that has two seals - preventing water from getting in the engine, and letting you know that one of the seals is leaking.

The slot on the end of the shaft mates up to a "ridge" or "key" on the "companion flange", which is bolted to a gear I think, inside the engine case.
Anyway, when the pump is bolted in place, the slot needs to be rotated so that the slot engages the "ridge", and so the pump shaft should turn whenever the engine turns.
If you can see the ridge on the companion flange, I'd first confirm that it turns when the engine turns. Then make sure that the pump shaft spins freely and turns the impeller. Then mate up the pump and make sure that turning engine turns the impeller.



Here are the hyperlinks for the pics:



https://www.marinepartseurope.com/en...50-26-309.aspx


https://www.marinepartseurope.com/en...50-26-308.aspx

[mike d.]

We have an Md22L ! Our pump is attached to the back of the motor ! The pump shaft should connect/fit to a slotted shaft in the recess, in the back of the block! It is/was a pretty simple fix once we got the kit parts ! Ours had the problem of a blown/worn out water seal, which was spraying water all over the back of the engine for some time before we bought the boat !

[jimbunyard]

Originally Posted by Sppro

thanks for everyone responses. I'm the proxy in the middle with my friend and I have 0 mechanical knowledge. We are talking about the impeller shaft.

Responses from my friend (to avoid my stuffing it up im just writing it word for word so it spans a bit of time, any assistance for me to forward on would be great):

We got the pump off and we can see the coupling. There is alot of hard greasy gunk in there which we cleaned out but we noticed a spring in the pump. Is that meant to push the coupling together? we cant seem to budge it at all, if there is supposed to be some play can someone please confirm the same?

It's not a spring actually, its an 0 ring. looks like it slipped out and there is some wear damage in the coupling but hopefully we can get it working.

are we supposed to grease the coupling?

There seems to be a fair bit of play, is there anyway to adjust the clearance of the coupling

Everything I say is based on what I see in the factory drawings, so, though I have a fairly large scope of experience, it should be taken with a grain of salt...

The drive coupling is bolted to the end of the cam; there shouldn't be any play.

I've no idea what spring or oring you're talking about.

Grease the interface between the coupling and the pump, it certainly won't hurt anything.

Without further information, I'd say that the problem may be with improper R/W pump assembly after rebuild, which allowed the pump shaft to float in the housing and migrate aft to disengage with the coupling. It is also possible that aftermarket or non-specific gaskets could have been used that increased the clearance between the shaft and the drive so that they eventually failed to mesh.

Or it could be a combination of both faulty reassembly and improper spacing,

Not knowing the spares situation, my recommendation would be to try and figure out if the pump shaft is as far toward the cam/drive as possible, and that there are as thin as possible gaskets between the pump flange and it's mounting surface.
.
Also, keep in mind that, if push comes to shove, in an emergency a bilge pump can be used to provide cooling water to the engine heat exchanger

[Karlostavitch]

Hi All,

Thanks for the assistance, I am the friend SPPro was assisting and I came across this thread while sourcing parts. All the feedback was helpful for troubleshooting the raw water pump coupling but I just thought I might share my experience in case anybody else comes across a similar situation.

The coupler on the engine looks like the image supplied by JimBunyard except if you imagine the corners were cut down, so a 3rd of the coupler on each end were only a few mm high, where as the centre 3rd was the full height. This seemed like a bad design while we were out there inspecting it and I suspect the part installed was not the original.
If you imagine the female version of that image, this what was on the end of the raw water pump. Looking at the exploded view of the raw water pump, there is meant to be a cir-clip between the bearing and the coupler, which we suspected but was missing and the shaft was able to move away from the motor on the bearing and let go of the coupler.
We ran water through the raw water pump with the bilge pump while we put locktite and on the bearing, then set the coupler clearance by extruding it as far as possible, then bolting back on the engine so that minimum clearance was achieved before removing and resuming running of the bilge pump for 6 hrs for the locktite to set.

This appears to have worked so well, as it has not failed since. I am now sourcing replacement parts for both sides of the coupler as both sides have been damaged.

Cheers

[Wotname]

^^ thanks for the feedback; it is always nice to hear how these issues get resolved.