Anybody seen this in their drip pan?

We bought our boat with an old ONAN MDJE 7.5 that we know is probably going to be replaced before long. The question is whether it will get us to Florida.

There are some fuel, oil, and coolant leaks that I haven't yet located so the drip pan is a mess. It was full of water with oil on top when we picked up the boat and there was a big clean up. The unit starts easily but goes through oil fast. Exhaust looks good.

After a few days of running, I found the drip pan full of grey mousse that looks exactly like what came out of my sailboat engine dip stick when the head gasket blew. It seems to be mostly water since spill pads don't soak up much of it. Paper towels do much better. It's so thick that an oil change vacuum sucker won't lift it.

The dipstick oil looks normal and I stuck a plastic tube deep in the oil sump bringing up no hint of water or anything that looks like the mousse. Oil looks great. Oil pressure is usually around 60 but the gauge ends at about 63 and is sometimes pegged there.

Is it possible that the vibration is just mixing up the stuff in the drip pan into this thick emulsion? I'm resigned to going through a lot of paper towels and doing a lot of clean up until we get south but wondering if something else is going on.

The 'grey mousse' sounds like exactly what I had in my Volvo TAMD41A when both raw water pump seals let go on my port motor during a 6-7hr cruise to Lady Musgrave Island letting sea water into the motor. The grey mousse in my case was mostly around the rockers. Can you take the rocker cover off to inspect - or just take the oil cap off and use a torch to inspect through that? I highly doubt such an emulsion could be created simply by water and oil being shaken in a drip pan.

For what it is worth - I rebuilt the RWP (on both engines) and used a wet/dry vac with a seiries of narrowing tubes connected to the end of the vac so I ended up with a very narrow, very 'sucky' vacuume tube that did help getting the goop out. Ran about 5 changes of cheapest (but correct grade) oil through it (running it for 1/2 hour in gear at idle in the dock in between each change) then filled it with 'good oil' and ran it for a few hours (max cruise speed) then changed oil and filters once more. Used the wet/dry vac in between each change. All good since then.

Good luck.

shufti said:

I highly doubt such an emulsion could be created simply by water and oil being shaken in a drip pan.

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Me too, thus the post. Oil fill on that engine is through a large combination dip stick / oil fill so a quick check of the valve and rocker area is difficult even after the sound shield is off.

However, I'm having a hard time seeing how something like this could be created inside the engine without showing up in the crankcase sump. I can see into it with a flash light and it is clean as a whistle, at least in oil sump terms.

Where is the mousse coming out of the motor from, Rog? I don't remember the oil i took out of the sump being 'mousse-ey' either - but it seemed to collect around the rockers. Maybe the aerating action of the rockers rocking is what caused the emulsion - and it just accumulated on itself. Although you mention moussey oil in the sump of the failed-gasket motor.

shufti said:

Where is the mousse coming out of the motor from, Rog?

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Don't know. I'll have to get the sound shield off. No sign of it anywhere on the engine from what I can see through the access panel.

I'll let you know.

Roger Long said:

After a few days of running, I found the drip pan full of grey mousse that looks exactly like what came out of my sailboat engine dip stick when the head gasket blew. It seems to be mostly water since spill pads don't soak up much of it. Paper towels do much better. It's so thick that an oil change vacuum sucker won't lift it.

The dipstick oil looks normal and I stuck a plastic tube deep in the oil sump bringing up no hint of water or anything that looks like the mousse. Oil looks great. Oil pressure is usually around 60 but the gauge ends at about 63 and is sometimes pegged there.

Is it possible that the vibration is just mixing up the stuff in the drip pan into this thick emulsion? I'm resigned to going through a lot of paper towels and doing a lot of clean up until we get south but wondering if something else is going on.

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Does this MDJE have the gear driven Onan raw water pump mounted on the front of the engine block just above the pan?

If so, it's lubricated by crankcase oil on one end and pumps cooling salt water on the other end of the same shaft. When the bearings and seals fail, they don't last very long, you get both oil and water out of the weep hole into the catch pan.
It can be converted to a belt driven Jabsco pedestal pump on the pump platform, mounted next to the Oberdorfer coolant circulation pump. It can run off the same belt if you choose. It's a simple conversion and solves a serious downside to that gen set.

Don't forget to install a gasket and plate over old pumps PTO mounting hole or you'll have oil splattered everywhere.

If oil looks clean on dipstick, not likely that water is mixing with oil in the sump.

If so, it's lubricated by crankcase oil on one end and pumps cooling salt water on the other end of the same shaft. When the bearings and seals fail, they don't last very long, you get both oil and water out of the weep hole into the catch pan.

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Sounds very similar to the RWP on my volvos. Running the motor will tell you instantly if the seals are gone as there will be water coming from the tell tail, as you say.

My MDJE has the Oberdorfer, Jabsco belt driven system too. If yours has this system you probably have a head gasket leak. Either way you need to fix this before you run much as this can cause major engine damage.

Kevin

Don't know how your grey mousse has come out of your engine, but I am with Shufti as to the source being water getting into your oil galleries through a leaking seal on your raw water pump (likely scenario)

This can cause a catastrophic engine failure, even after you have it al cleaned up.

This can cause a catastrophic engine failure, even after you have it al cleaned up.

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Not wishing to argue - and I know they are two completely diifferent motors - but my (trusted) Volvo mechanic wasn't too concerned about it (after I told him how I treated the problem). He was more concerned that I'd tried to run a Diesel/oil mixture to 'clean out' the galleries as he's seen it done in the past. I can;t remember what the exact problem (he explained) with doing that is/was though. I hadn't done it luckily.

As you are planning, remove the sound shield. Then do a really good cleanup of the genset and drip pan. Then put several pads and paper towels around the genset, run it and you should hopefully be able to find out what is dripping and from where.

Water finding paste may be useful. Put it on the dipstick and if there is water in the oil it turns bright red. Works in fuel also.

Kolor Kut is the brand I'm familiar with.

Also, that is a Kubota motor, you don't have to buy all your parts from Cummins/Onan.

Guys, he has milkshake in the drip pan, he says the oil in the sump looks good. If oil looks good in the sump, the engine is fine.

This old beast is not a Kubota, it was made by Onan. Big 2cyl. Later models are Kubota.

I can now answer my OP question in the affirmative.

I've been researching generator replacement in two days away from the boat. This morning started at the ONAN dealer confirming that parts to rebuild the waterpump are unobtainable through any normal sources. Went to the boat to meet with mechanics about the logistics of gen set replacement and confirm wisdom of this group.

The milkshake froth in the drip pan had become just a think layer of clear oil on water. I ran the generator and could detect no hint of oily or water discharge from the pump weep hole. I did find a small oil leak around a bolt but could find no other significant fluid leakage.

Then, I looked in the drip pan and the milkshake froth was growing like a mold around the rubber mounting feet and away from the sides of the pan. An hour of running would have covered the entire surface of the pan and a day frothed it up into overflowing.

I sucked out as much as I could and refilled the oil which turned out to be down only 1/2 quart after running all the way from Buffalo to Albany. Not too bad.

So, the vibration from the pan can create impressive amounts of this stuff, at least on our boat. There was a sloppy oil change just before we bought the boat and we spilled some coolant draining and flushing. The boat sits down by the stern and there was more of this witches brew back out of sight than I thought.

The mechanic thinks this gen set will go for a long, long time. I'll just have to keep that drip pan well cleaned out.

There is a forum that has a description of the electric raw water pump retrofit. I did it and am glad. Put 500 hours on a 110v pump that costs $120. Wish I would've done it years ago.

I have the same generator and the oil pressure gauge indicates 30 PSI. I looked in the Operators Manual and unless I missed it there is no mention of what the gauge should indicate under normal operation.
So now I'm not sure if your 60 PSI is to high or my 30 PSI is to low.

I use Delo 30 wt. pressure is about 32lbs

FOG said:

So now I'm not sure if your 60 PSI is to high or my 30 PSI is to low.

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I never had pressure gauges before, just alarms. My main engines run at 40 right after start and 55 - 60 in cruise. I can't see that the pressure should be much different for a smaller engine.

I was concerned because my gauge was pegging, however it only goes to 60 and backs off a bit when the engine warms up so I think my operating oil pressure is probably 55 - 58.

My manual does say that there is no oil pressure relief setting on the engine. Your pressure sounds low. Pressure goes down as engines age, one of the reasons the mechanic I spoke to said we'll probably be living with this rattle trap for a long time.

If the raw water pump is the same as my raw water pump 6500 watt MCCK onan, then yes the water pump seal is available direct fit from U. S. Seal MFG. # PS-163.

This will have a SS instead of brass cup base. It will not have the large flat ceramic washer, just reuse your OEM ceramic washer. Oberdorfer pumps use the same flat ceramic washer in their pumps, so you could get one anyway. It looks like a fender washer with a 5/8 inch center hole which has a rubber grommet on it's back to seal to the pump shaft.

Price I paid was under $10 for the seal.

For example
http://www.hottubwarehouse.com/us-s...ofvmYqcSQXx-h7Xs-wD0w3skeRHwQvpfqPxoC-irw_wcB

shows the seal with the washer, #32154.
http://www.oberdorferpumps.com/pumps/centrifugal-pumps/60p/

Roger Long said:

I was concerned because my gauge was pegging, however it only goes to 60 and backs off a bit when the engine warms up so I think my operating oil pressure is probably 55 - 58.
.

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My MDJE manual lists minimum oil pressure at #20 on page 13 under Starting. But same here, pressure is like 50 lbs at start, drops down to 35 after running for a few minutes. It's been that way since the boat was new.

Just to be sure I understand correctly, when you run the gen set

1) the oil level in the crank case goes down faster than normal consumption

2) Oil appears and accumulates in the drip pan

3) Water (or perhaps coolant) also appears and accumulates in the drip pan

4) You have observed the engine vibration turning the mix into a mike shake.

With that you have already gone a long way to diagnosing the problem.

Have you checked to see if your coolant level is dropping? Any way to figure out if the "water" is sea water, coolant, or something else?

It seems you just need to figure out where the fluids are leaking from. I know, easier said than done, but it's definitely easier than randomly replacing parts.

I've found that the heavy duty blue paper shop towels that you can buy in any hardware or automotive store are great for tracking down leaks. Whatever fluid hits them leaves a very evident stain because of the towels blue color. Stuff a bunch of them in strategic places in and around the engine, you you will pretty quickly narrow down where the leaks are coming from. I've even taped or zip tied them around things that I thought might be leaking. I had one stuffed into a corner by my coolant pump weep hole to nail down a leak that I had.

Find the leaks, then figure out how to fix it. The raw water pump sounds like a strong candidate based on what people here are saying about this particular unit, so be sure to dress that well with towels. I'm not familiar with that gen set so can't offer specific advice.

I had that gen. But a Honda portable if u have to. The Onan is prehistoric.

jrs1958 said:

I had that gen. But a Honda portable if u have to. The Onan is prehistoric.

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My 6.5 MCCK with water lift muffler is quiet. Just makes a whirring sound. 1800 rpm, sure it is from 1970 also. It is FWC and so then has survived. It also has control-o-matic, it autostarts on demand, which seems like a worthwhile idea to save fuel.

I installed a wire to bypass the DC charger converter from wanting to always run the gen, basically put the wire to the charger before the sense circuit..

Edelweiss said:

My MDJE manual lists minimum oil pressure at #20 on page 13 under Starting. But same here, pressure is like 50 lbs at start, drops down to 35 after running for a few minutes. It's been that way since the boat was new.

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Thanks. Found it on page 15 of my manual. Says the same thing.
BTW the pressure in mine is 45 lbs at start up, then drops down to 30 once warmed up. Maybe a few more hours or lower viscosity oil.

The 6.5 MCCK gasser is a very social machine. Not real accurate governor or regulator, but very quiet and smooth. Much like BMW opposed twin bikes.

MDJ diesel twin is a rock crusher. Oil pressure if anything over 20psi hot should be fine. If bottom end does not send chunks across engine room, oil pressure is good enough. And noise level won't be much different.

Just kidding, a little bit.

Ski in NC said:

The 6.5 MCCK gasser is a very social machine. Not real accurate governor or regulator, but very quiet and smooth. Much like BMW opposed twin bikes.

MDJ diesel twin is a rock crusher. Oil pressure if anything over 20psi hot should be fine. If bottom end does not send chunks across engine room, oil pressure is good enough. And noise level won't be much different.

Just kidding, a little bit.

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Mine burns 1/3 gallon per hour while running the heat pump-AC, charger-converter and fridge.

There is a vaccuum boost along with governor spring to kelp maintain cycles close to 60.
Under heavy loads, the volts will drop but I compensate by having it set about 123 to 125 with no loads. I also have 8 gauge wire, likely should be 6 gauge wire to the distribution panel, but this was installed with that wire many decades ago and it just works fine anyway.