06 Yamaha F150 - Oil in prop exhaust, but what kind of oil?

[vb2oc0371]

I changed my LU oil a month ago and haven't used the boat until this morning. I took it off the lift, started it up and it was puffing greyish white smoke and made a colorful little oil slick my old lady neighbor just loved. It's been below freezing on quite a few occasions since I changed LU oil, but I make sure the engines are down so any rain or snow doesn't collect and freeze. I popped open the lower gear case oil drain plug looking for water, but only clear new looking oil barely oozed out (It was below freezing at the time). I would doubt any water would have time to intrude the LU since the boat has been high and dry since the oil change. One thing though, I had the engine tilted all the way down when I checked the condition of the oil after my Capt Hazelwood event. Should I tilt it up when checking for water in the oil? I'm going to do a pressure test next.

Here's what it looked like going back on the lift:







My LU oil was not black when I checked it this morning so I'm not thinking water in the gear case? Oh, I did have the top fill vent unplugged when I pumped LU oil from the bottom drain port. Seems like a few folks don't do that and bust seals, but no, not me.

Thanks in advance for any helpful info.

[TownsendsFJR1300]

You can remove the lower plug, crack loose the upper plug and let some oil out to check it. It can either be trimmed up or down, oil will come out.. Top off with the LU level.

Sometimes, if the engine is trimmed in all the way, oil will seep past the rings and smoke upon start up. It burns off but does leave a nice BLUE cloud.

How do your spark plugs look? One any oily??

If the lower unit oil looks good, the plugs look good, run it on some muffs and watch for bluish smoke(oil burning).

For S&G's, I'd pull the prop, check for any fishing line and also inspect for any oil oozing out the prop shaft seals.

[99yam40]

what does the oil on the prop smell like?
LU lube smells a lot different than motor oil.
Have you checked the oil level in the motors to make sure not over full?

[vb2oc0371]

I've always stored my boats in boatels, so this in the first one I've owned that's been exposed to the harsh winter freezes. I kept the engines in a negative tilt position since I changed the LU oil (one month) to keep rain & snow from freezing in the prop hub. Wondering if that comprised the seals?

[vb2oc0371]

what does the oil on the prop smell like?
LU lube smells a lot different than motor oil.
Have you checked the oil level in the motors to make sure not over full?

The leaking oil had a funky smell, so went to the shed and got some a bottle of new gear lube oil then compared that to what I wiped off the prop. Can't say they matched up exactly, but similar. I'm going through the checklist of what to look for and oil levels are on the list.

Thanks.

[vb2oc0371]

How many hours on the motor? Could just be oil leaking into the cylinder through the valves, just like an old car will do if it hasn't been run in awhile. Or it could be a prop shaft seal.

I would run the boat and then check the lower unit oil. If it stays dry and the smoke goes away I wouldnt worry about it.

The port engine (the biggest leak) has 1006 hrs. The starboard engine has 1032 hrs. (leaks to a lesser degree) from the prop exhaust area, same symptoms. Both started this leaking at the same time, but I didn't notice the starboard engine leaking because the ports slick was hiding it. The will only leak if the engines are running or if I'm flushing them. I put it on the lift and watched for a while and no drips. Since both engines exhibit the same symptoms, with the port being more severe, It's got to be an external factor either with the LU oil change I did, or the prolonged freeze and water left over in the engines that froze.

I bought this boat last fall and have put about 50hrs on it. The seller was a good guy. I believe he was honest and not a flim-flammer when he said he had the 1000hr maintenance done. Thing is, his mechanic blew off all my requests for the maintenance history, so who knows. I checked the engine oil today. It needs to be changed for sure, but I couldn't believe the dip stick reading on the port engine, the engine that's puking oil from the exhaust. It was about 3/4 up the dip stick, waaaayyyy over the MAX line. I verified the same reading about 6 times in a row. The starboard engine oil level looked normal, just below the MAX line:

Port oil level: (bad pics but maybe you'll get the idea)


Starboard oil level:

I sampled the gear lube and here's what it looks like:


I pulled the prop:

[99yam40]

did you take a wif of the motor oil to see what it smelled like.
may have fuel contaminating it.
how do you normally run these motors?
Lots of slow *****ing and idling

Change the oil and filters.

and check on the stats to make sure they are in there and not stuck open?
Might even test in a pot of water as you heat it up to see what temp they open and close.

You need to be checking the oil frequently to see how things are going

[vb2oc0371]

did you take a wif of the motor oil to see what it smelled like.
may have fuel contaminating it.
how do you normally run these motors?
Lots of slow *****ing and idling

Change the oil and filters.

and check on the stats to make sure they are in there and not stuck open?
Might even test in a pot of water as you heat it up to see what temp they open and close.

You need to be checking the oil frequently to see how things are going

Thanks for the insight, I really appreciate it. I don't ***** at all, I cruise to the wrecks at about 3500 RMP, and shut down when I'm anchored. But now that you mention it, about a month or so ago, I had to run the engines at idle for 8-9 hours straight. Long story short, I went fishing, got home and the tide was so low I couldn't get on the lift. The temp dropped from 40 some degrees to the mid-****s when a nasty NW front moved in that evening. I couldn't put the engines down when I was tied up to prevent freeze over because it was too shallow. I had to situate the boat in the middle of the canal at idle all night so I could keep the engines wet and warm instead of freeze dried. So yes, I do a lot of idling, all at once and it was not a pleasurable experience.

[vb2oc0371]

On both engines, a coolant passage hose nipple is badly corroded possibly restricting water flow making the thermostat act out?





I have low water pressure at my dock. When I flush my engines on the hose adapter or muffs, they don't pee out of the hole located on the starboard side just under the cowling. I'm still blurry on really what's really getting flushed and what's not when the engine doesn't pee.

[TownsendsFJR1300]

Have YOU changed the oil in both engines since owning it?

If so, I'm assuming it was set about half-ways up the dip stick HASH MARKS?

Does the oil smell like fuel at all?

As noted previously, change the oil and filter's (both engines) ASAP. The oils very nasty and WILL be darker than what shows on the dip stick once out.

The very high oil level is NOT good at all for that engine (or any engine).

Why its so high is the question of the hour-

[vb2oc0371]

You guys called it with the thermostat being stuck open. Heres what I did to hopefully resolve the issue and the results of my work:

1. Oil/Filter changed (Looked like almost 10 quarts of oil/gas mixture was pumped out)
2. Replaced stuck open thermostat + gasket (in poor shape, see pic below)
3. Changed out spark plugs (black & oily)

I did the same to my starboard engine as well despite it's better behavior.

So after I did this work, I haven't been able to get the boat out and open it up. I have lowered into the water and ran the engines at idle, heard the RPMs level out after the engine warmed up and the thermo open, so that's good. I throttled up to about 2500 RPM out of gear. Prior to the work, when the engine was in full OPEC mode, I observed the oil slick from the exhaust, but that's gone. The thick blueish/whiteish smoke output has been reduced by about 90%, but there's still some visible smoke being emitted when the engine is running, more so as I add power. I ran it about 10 minutes and the light smoking didn't stop, but it sounded okay. Again, way less smoke than when it was making oil, but I still have some concerns. The starboard engine's exhaust output appears to be light and normal.

So here's the questions. Since I haven't dealt with this issue before, should I...

a) Do a compression check to make sure there's no internal damage from the oil making episode, or...
b. Do step (a), then if there's no compression issues, take it out and run WOT for 10-15 minutes to see if that clears up the smoking issue, or...
b) Call my trusty Yamaha guy to have look at it because most likely my engine is sicker than it looks and sounds?


On another note, here's a pic down the coolant passage where the thermostat has been removed. I have water pressure issues at my dock that results in my engines not peeing when I flush them. This is not really what I wanted to see. I'm going to buy a booster pump, but need to be careful to not go over 50psi when flushing or it can have a in the coolant system (according to the manual;?) Would this level of corrosion inside the engine be of huge concern, or business as usual assuming the booster pump gets water up in there?



Thermo stuck open - If the previous owner's maintenance records are correct, this thermo had a little over 100 hrs on it. Dunno about that though...



Thanks again for the guidance on tracking this oil spill back to its source. Much appreciated.

[TownsendsFJR1300]

I'm on city water and have about 70 PSI water pressure with 3/4" or 1" PVC lines to the lift (forgot, I buried them 20 years ago) lines to the back yard.

There's no problem with the higher pressure if using the muffs as the water pump will only pump so much water into the power-head..And the engine hasn't ever set off an overheat on the muffs-NEVER.

You had so much "oil" in the engine and places it shouldn't be.
I would run it and make sure its (the old oil) is flushed out completely.

Doing a leak down test would be much better than a compression test. You'll get a good idea of the health of the top end of your engine-piston, rings, valves, block, etc. It won't tell if you have any lower end rod to crank issues (from lack of GOOD OIL) so pay close attention to any new noises

You want ALL the excess oil (say in-between the rings) gone/burned off BEFORE TESTING. That'll mess up your readings-reading higher than normal.

Good luck and please post back what you find..

[fairdeal]

The port engine (the biggest leak) has 1006 hrs. The starboard engine has 1032 hrs....

I bought this boat last fall and have put about 50hrs on it. The seller was a good guy. I believe he was honest and not a flim-flammer when he said he had the 1000hr maintenance done.

Thermo stuck open - If the previous owner's maintenance records are correct, this thermo had a little over 100 hrs on it.

Looks to me - from the appearance of the oil, and that thermostat -

that the previous owner is a lying sack of sh*t

and his "maintenance records" are pure fiction....

But if you believed him, why did you "change my LU oil a month ago" ?

[vb2oc0371]

Looks to me - from the appearance of the oil, and that thermostat -

that the previous owner is a lying sack of sh*t

and his "maintenance records" are pure fiction....

But if you believed him, why did you "change my LU oil a month ago" ?

Had some fishing line wrapped in the prop shaft so I went ahead and changed LU oil making sure the oil seal didn't get comprised allowing water intrusion.

Thanks.

[fairdeal]

well, I "second" Scott on suggesting leakdown testing as a useful indicator of "health".

good luck

and while you're at that, maybe have a look at the internal engine anodes