M2 Housing Cracked

[AirSniper]

I know this is not good, but I suppose I am looking to understand how bad it is.

I have been hearing a "ticking" or tapping, particularly at idle/low rpm. Thought maybe an exhaust leak or FOD in the impeller - the noise went with rpm.

Pulled the boat & without the lanyard, turned the engine, the noise is clearly from the drive/gearbox. Was going to change the gear oil, and found this housing cracked. I did change out the oil, and with a magnet, I pulled out the metal pieces in the other pic. the oil was dark, but no sign of water, and it seemed to drain a sufficient amount.

After the oil change, the boat seems to run fine except for the tapping noise which continues. The noise either goes away or is drowned out at higher rpm.

Looking at ebay, there are at least 2 for sale in the $250-$350 range, one of them shows the same crack in a pic. Looking through the forum, a few pics have this crack too.

Lots of questions:

So, the metal is clearly gear chips. I havent seen inside the housing, but it would seem that the mis-alignment in my crack would offset the mounting of the gears and cause noise/chips. Is this a correct assuption?

is this common in the M2 design?
can it be fixed?
does anyone have any photos of the inside of the housing (to show if this aligns gears)?
Since it holds oil, and doesnt let water in, and the gears are already damaged - should I run it until complete failure?
Does the engine need to be removed - can i remove the housing from below?
what could cause this...quick accelerations...etc?

Thanks in advance, I would recommend all M2 owners to take a look at their housings. from what I've seen, this is common enough to give a close look at when possible.

 

[Dr Honda]

Well.....


The second picture is not good. Are we sure it's gear, and not just a bearing failing? I guess it doesn't mater at this point, since the pump needs to come apart. So, I will just go down your list...

1) Are you sure it's a crack? Is it leaking oil? There is a casting line in the pump housing, and that's why you see it in other pumps. If it's a crack... it will be oily.

But... the gears aren't aligned using the case at that point. The input shaft comes down from the top... and the pump shaft goes front to back. Gear mesh is set with shims. SO... if you are loosing a bearing (possibly the clicking sound) the gears will go out of align.

2) Not sure what you are asking on this. (Is it a common in the design)

3) Anything can be fixed. But if you are paying a shop... they the labor may be expensive.

4) I don't have photos, since the pumps on these boats are generally very tough. The normal issues are with the stator bearings, or wear ring.

5) I WOULD NOT run it to failure. Right now, it can probably be fixed. (Even if there is a crack) If you run it to failure, you may have to replace the entire pump. Not to mention, you will be stranded somewhere... and it will ruin a day on the water.

6) Yes, the engine has to be removed. Basically... the pump unit, mounts to the boat... and then the engine mounts to it. So, engine out... adaptor plate out... cables removed... pump goes down.

7) Sometimes there's no reason. If the boat is new to you... there could have been water in there before... and it caused damage. Or... a bearing simply failed. OR... the last owners sucked up a lot of rocks, and cracked a gear. Oh... also... using anything other than the Quicksilver hi performance oil. Using regular gear lube, or the outboard oil will not protect the gears correctly.


Here's a pic I found of my pump. It's not the best pic... but you can see that casting line.

 

[AirSniper]

Thanks Doc. Once I take it out of the water, I will take a closer look to see if it is a casting seam. There is definitely an offset that is real, just like the pic shows (the lower part in the pic is definitely "raised" downward).

There was really no sign of water or grease where it shouldn't have been. Perhaps being magnetic, that may point to gear or bearing? I don't know if the gears are magnetic but would expect the bearing to be.

I added the quicksilver gear oil, but what i took out was likely not - it was black & smelled of regular gear oil. I didnt think to sniff the Mercury oil before i added.

I've got perhaps a few more days of summer here, and will certainly stay close to shore. I will update any new findings.

 

[Sportster-2001-951C-Stock]

I don't think that's a crack, either.

Sometimes gears just go for some reason but did the oil seem thin like motor oil? Chunks floating around do lots of damage and I predict what's remaining won't last long at all.

Mercury Hi Performance gear oil smells like regular gear lube to me, doesn't smell like a dead whale or something IMO. You have the bottle still, for a sniff. Stick with HI Performance, it's good lube.

 

[AirSniper]

Seemed to be similar viscosity as the blue mercury lube... but yes, dead whale - great description. Permeated the entire house for a day. I supposed the last service probably used the wrong oil.

 

[Dr Honda]

.............. Perhaps being magnetic, that may point to gear or bearing? I don't know if the gears are magnetic but would expect the bearing to be.

Both will be steel. So, it could be either. I guess the parts are too small to tell if it was gears, or bearings.

I added the quicksilver gear oil................................

OK... but was it specifically Quicksilver "High Performance" gear oil?? If not... you have the wrong stuff. The standard gear oil, or "Lower Gear Case" oil won't properly protect the sportjet gear case. There's just too much load on this system.

But... this is where the problem may be. If what came out was black... it's either wrong, or very old.

I've got perhaps a few more days of summer here, and will certainly stay close to shore. I will update any new findings.

I still say it's a bad idea. Here's why...

The best case would be that you simply kill the gears, and you go home. The worst case would be... you jam a gear... bend the shafts, and shatter the case. AND... along with that... if you stop the engine instantly (from something in the lower jamming) you could break your crank shaft... or bend a rod. You have to remember, that there is a 20 Lb flywheel, 3ft above the gear case, that doesn't want to stop instantly. And, something in the middle will become it's casualty.

So, being... well... dumb... you can possibly lose the engine along with the pump.


Right now... it's potentially a weekend, and $100 or less in parts. Later, it could be $10k for an entire sportjet unit. Oh... and the only new units are 200 Opti sportjets. (so it's an expensive down grade)

 

[AirSniper]

I will check the oil, bought 2 quarts. I know it was Mercury high performance gear oil.
The largest of the chips appears to be a gear, seemingly machines edges on it, so I will make that assumption. Unless the bearing has a metal cage, the other parts are also sharp.

I definitely understand and agree with your cautious warnings. We'll see if I can resist the temptations of the last nice weather days.

 

[Sportster-2001-951C-Stock]

I agree you're better off maybe MUCH better off tearing into that gear case for reasons listed, not worth taking the chance.

If you have a spare pump (used but checked) on the side the swap should go fast.

Those chunks look like broken gear teeth to me, the bits get into the bearings and chew them up so bearings likely are necessary.

FYI, I've never been into a sportjet pump so I'm no expert but plenty of stern drives.

 

[shep]

Hey AirSniper!

Re: Your question: Looking at ebay, there are at least 2 for sale in the $250-$350 range, one of them shows the same crack in a pic. Looking through the forum, a few pics have this crack too.

I was under my boat on the weekend, and thought the same as you last year, but it is definitely not a crack, but the casting seam. I took a pic of mine, please see attached.

 

[AirSniper]

Thanks Shep! I am starting to be convinced & sure hope you're right. I will update once I have definitive evidence. Still in the water just yet.

 

[AirSniper]

Finally, the UPDATE:

The "crack" is clearly just the casting seam, so not the issue.

$7K !!
the gears were missing teeth, the bearing shot. The shop recommended replacement of the entire housing/shaft/wear ring. Probably could have saved a few parts, or tried to find ebay parts with unknown history, but went for the new parts package.

I have the assembled housing in the garage, one day I may tear it down and post some pics. Not sure what to do with it, the housing may be able to be salvaged.

The shop I went to specializes in jet pumps and clearly knew the design and engine, i was very comfortable in their recommendations and capabilities. They said my failure was something they dont see, so I'm still wondering about the cause. We had the wood chip incident which acted like it was clogged with weeds, but no issues resulting from that - immediately anyway.

The $7k did include some add-ons, filters/plugs/anodes/belt...other things which are easier taking care of while disassembled. The lube oil was ~ 2 years old & i am sure to be more vigilant in the future.

Thanks to all for the input and insights, now it is time to get it in the water.

 

[Sportster-2001-951C-Stock]

Yeah, not cheap but at least you can enjoy the boat this summer!

Usually when I see gears and bearings torn up it was traced to an issue with the lubricant being the wrong type or contaminated, FWIW. Maybe something like rocks went through your pump at some point, that's another possibility I suppose.

 

[Dr Honda]

$7k is nuts. Check ebay... you can probably find an entire used/good M2 for $1k.