Emulsified Oil

Simon B · 09 May 2007, 13:37

Not sure how serious this is or exactly what it points (though I do have an idea)

The engine oil in our Yam F100A 4 stroke (carb) has emulsified it's been changed and after a run up shows signs of the same again.

Has anyone else had this problem?

codprawn · 09 May 2007, 15:13

Deson't sound too clever - obviously water in the oil. On most engines it would indicate head gasket failiure but maybe different on an outboard?

It could be serious condensation problems - maybe caused by the engine running too cold? If you take a sample of the oil and let it sperate out check if the water is salt or fresh - you can either taste it or measure it's boiling point or even evaporate it and see if there are salt crystal left.

jyasaki · 09 May 2007, 16:38

Milky oil...

Could be water, as Cod says. If it's water, I'd suspect a head gasket.

Could also be fuel getting mixed in. Take a sniff and see if it smells like gas. If it does you've got the condition known familiarly as "making oil". Don't know about the F100, but the F115 is very prone to this (fishermen who troll a lot report this pretty often.) The short version is that unburned fuel gets to the crankcase, condenses, and mixes with the oil. Short term solution is a hotter spark plug and less running at low rpms.

jky

Simon B · 09 May 2007, 19:13

Cheers JKY,

We're going to run some flushing oil through, it's had one change already, it's happened quite quickly since the last change and during the last trip out it miss fired a number of times but appeared to clear. I put it down to some crappy fuel as it appeared to disappear when we changed tanks. I'll wait a bit before I get morosely depressed. The reports were of strings or spirals of the emulsified stuff forming soon after the new change.

Sixy_the_red · 10 May 2007, 12:47

Check your plugs too - if the head gasket's gone big style, or the head / block are cracked and cooling water's getting into the barrels the plugs will appear 'jet-washed'.

Paul F · 11 May 2007, 07:12

Quote:

Originally Posted by Sixy_the_red

Check your plugs too - if the head gasket's gone big style, or the head / block are cracked and cooling water's getting into the barrels the plugs will appear 'jet-washed'.

Could also be adaptor plate gasket/ water pipe seal at the base of the powerhead.
Paul

Simon B · 11 May 2007, 07:40

Got a sample of the oil, its a couple of days old now, however, all the "emulsification" has gone its a charcoal grey colour and reeks of fuel. It certainly doesnt look like the emulsified stuff I've taken from gearboxes at work. The chaps who drained it said that the dipstick level was very high.

Sixy_the_red · 11 May 2007, 08:27

Quote:

Originally Posted by Simon B

Got a sample of the oil, its a couple of days old now, however, all the "emulsification" has gone its a charcoal grey colour and reeks of fuel. It certainly doesnt look like the emulsified stuff I've taken from gearboxes at work. The chaps who drained it said that the dipstick level was very high.

Sounds like float needles - if they're not seating properly then the fuel pump(?) will simply push fuel past them. The bowls should have overflows but I'd guess if you're leaving the engine tilted then its likely that the fuel will drain into the engine. Fuel shouldn't cause the oil to emulsify though, unless its got dry fuel or preservative in it maybe?

(I once drained 4.5l of 'fluid' out of a 2.5l sump on a bike so you're not alone!

)

jyasaki · 11 May 2007, 16:25

Quote:

Originally Posted by Sixy_the_red

(I once drained 4.5l of 'fluid' out of a 2.5l sump on a bike so you're not alone!

)

Was that the old "Fill it up 'til it overflows out the dipstick tube" trick?

jky

Sixy_the_red · 12 May 2007, 08:41

Quote:

Originally Posted by jyasaki

Was that the old "Fill it up 'til it overflows out the dipstick tube" trick?

jky

Naa, more like the 'leave it stood for too long with leaking float needles so it fills the engine up with petrol, sorry gas

' trick!

Simon B · 08 June 2007, 07:41

Engine now in bits;

Head gasket ok
Powerhead gasket ok

No other signs of areas where obvious oil "water" mixing can take place. However, the oil samples taken are now dark in colour there has been no separation into oil and water and it still reeks of unburnt fuel.

What did the oil look like in the engines that were "making oil"?

Sixy_the_red · 08 June 2007, 10:06

In the engine I had that was 'making oil', the oil looked normal if a bit runny - I don't know about o/b 4 stroke oil, but the stuff used in bikes is 'natural' (ie crude based rather than synthetic) so the petrol mixes with it normally.

The dark colour could be as a result of carbon deposits being washed down from the bores into the sump?

jwalker · 08 June 2007, 13:46

It's unlikely that the fuel will be running freely into the engine if the fuel tank is lower than it. I don't know your engine at all but it was a problem commonly associated with a leaking diaphagm on a camshaft driven mechanical pump. It could be a clue...or not.

Simon B · 08 June 2007, 14:34

Gadzooks JW! How could I have missed the obvious to check. I'll see if this can be verified. It sounds logical in terms of a ready route to put fuel into our oil. The miss fire we experienced before this started still seems a little at odds, or just not connected. Next step is see if we can have the oil analysed.

RIB BOI · 08 June 2007, 19:47

Its so cheap to have the oil analysed it would of been the first thing on my list of things to do. It can show you problems befor thay do to much harm. like bearing failings.

RIBBOI

jyasaki · 09 June 2007, 07:54

The Yamaha problem had something to do with fuel/air blow-by past the rings into the crankcase, where due to lower temperatures from low speed operation, the fuel condensed out (or something) and mixed with the oil. Higher speed operation caused a rise in temperature that alleviated the problem.

It apparently takes a while for the level to rise noticeably, but it's happening enough that I've heard of it from several different sources. As I said, the first line fix was a hotter spark plug. I don't know off-hand what else was done to correct the problem.

Sorry, Simon, I don't know what the fuel contaminated oil looked like, but the smell should be a fairly positive indicator. The remaining question, of course, is how it got there.

You can hit The Hull Truth forum (thehulltruth.com) and do a search for "making oil"; you should get quite a bit of information.

jky

Simon B · 10 June 2007, 12:29

Cheers jyasaki,

Trolled through thehulltruth and will be pursuing their fix list once the, motor is back together. Its not something I've heard of much here but I guess it would only be divers who would see this?

Will let you all know how we get on.

jyasaki · 11 June 2007, 01:59

Quote:

Originally Posted by Simon B

Its not something I've heard of much here but I guess it would only be divers who would see this?

No, I think divers (or most divers, anyway) tend to run fairly high speed most of the time. Not much time spent idling along except when looking for structure to dive on. Most of the running is point A to point B fast stuff.

The problem is more prevalent among blue-water fishermen and lake trollers. Those guys run high rpms to get to their fishing grounds, then idle along trolling for hours at a time.

jky

Simon B · 29 June 2007, 14:18

Oil analysis back from Caterpillar in Leeds; some water but a lot more fuel so it looks like we were "making oil" in some form. We'll monitor and then see if it re-occurs, if it does then we'll have to work down the list of known fixes from US will keep posting results.

This is the first time we have seen this and the only thing different in how we used the engine was allowing it to run on tick over (not in gear) for about 3 hours to charge the flat battery.

Simon B · 18 February 2008, 15:28

Just had the motor back from it's annual service, thermostat was jammed in open, thus engine has been running cool all year (or part of) Will see why it's jammed in a bit.