Running the outboard hard without oil....now what?

[gamayun]

Soooo....go easy on us. My best bud and I and her husband are shooting across San Pablo Bay to meet up with friends in Petaluma. They have a single Yamaha 50 HP. After 2 hours at around 5000 RPM it starts sputtering a bit then dies. He checks the oil and nothing is registering on the dip stick. We got a tow to Loch Lomand. The outboard turns over but is not firing up. I went through the manual and a bit of Googling. Could it be the spark plugs? Did we blow a head gasket? Hubby's not telling his mechanic that he ran the motor with no oil so the mechanic has been texting him about checking the fuel and such. Alrighty then CF friends. Lay it on us. How bad could it be? Can we check anything with limited tools and know-how?

[pesarsten]

Pull the spark plugs, you will likely see them fouled with melted aluminum.
Please post the findings for us.

[Compass790]

It could be bad but try taking plugs out & squirting a little bit of oil in the cylinders ( say a teaspoon) & then firing up.Whilst you have plugs out make sure they are sparking before re-installing. Also try spraying a little Wd40 in the air intake whilst cranking as valves may have seized. I'm assuming 4 stroke?

The good news is it's not seized. Yes you could have blown the head gasket. Was the oil down from lack of checks or another reason?

[JPA Cate]

It doesn't have oil injection? Those will cut out when the oil gets too low.


The gory, blood-sucking side of us wants to see pictures, as a lesson to us all.

Ann

[Compass790]

Originally Posted by JPA Cate

It doesn't have oil injection? Those will cut out when the oil gets too low.


The gory, blood-sucking side of us wants to see pictures, as a lesson to us all.

Ann

She does not say wether it is a 2 or 4 stroke. Yet that is

[gamayun]

It's 4 stroke. He said he checked the oil before we left but later said he might not have warmed the engine so not sure what he actually read on the dip stick. When I looked to see if there had been any evidence of a leak, he'd spilled some oil inside while filling up the crankcase. So still not positively sure about why it ran dry. I'm liking that oil injection types will cut off rather than blow up when run dry. That's good! Thanks for all the suggestions so far. I will definitely report back and post pictures if there's something gory to show. But hang tight. It's just 6 AM for us now so gotta make coffee and breakfast first

[rslifkin]

If you're lucky it's got a low oil cutoff and just needs a refill.

[thomm225]

Exactly, step one is to fill the oil up to the proper level.

I have been running my outboard hard here lately. It's only a 5 hp 4 stoke but sometimes I have had to run it 4-5 hours to get home.

I checked the oil recently and there was only about 1/8 " showing on the dipstick which when full is like 3/8" to 1/2" oil showing.

Point is the motor holds 15 ounces and to bring the oil back to the correct level only took like 3 ounces so there would have still been plenty of oil in the engine if it was just below the stick and not showing.

(but) my engine never quit so it sounds like there is another problem with your engine. It's strange that it didn't seize up.

I had an impeller fail one time and the engine over heated then wouldn't start until it cooled down some. After is cooled down I was able to start it long enough to get the boat into my slip.

Recent 18 mile sail/motorsail almost straight into the wind to get home after sailing 3 hours to get lined up.

https://www.youtube.com/watch?v=ri0c5GnZ1I8

[Lake-Effect]

Originally Posted by gamayun

Soooo....go easy on us. My best bud and I and her husband are shooting across San Pablo Bay to meet up with friends in Petaluma. They have a single Yamaha 50 HP. After 2 hours at around 5000 RPM it starts sputtering a bit then dies. He checks the oil and nothing is registering on the dip stick. We got a tow to Loch Lomand. The outboard turns over but is not firing up.

Ouch.

A 2019 manual. In a quick look, I couldn't find any info about an oil safety switch. Was there no low-oil alert, over-temp alert, or buzzer? The way you describe how it quit suggests some sort of protective shutdown.

I would just treat it like any outboard that won't start. Fill with oil (maybe a few drips of oil in each cylinder) disconnect the spark plugs and turn it over a few times to distribute oil and feel for compression, inspect the spark plugs, re-install and try... if still no start then check for fuel and spark, check compression, etc etc.

Good luck. Report back please.

[gamayun]

It was late night when I posted that the engine is 50 HP. It's actually 115, and 20 years old.

[wallda]

First step is to bring the engine back to operating conditions. Add and measure the amount of oil it takes to restore the normal amount of oil (if it is a four stroke). Compare this to the published oil capacity to find out how much oil was actually in the system. See if the engine will start. If it starts do a complete PM. Drain all oil, change oil filter and start over.

If it doesn’t start check compression on all cylinders, inspect plugs for signs of metal, open oil filter and check for metal.

The bottom line is you have low compression or metal you are probably better off buying a new engine then rebuilding.

[wallda]

Originally Posted by gamayun

It was late night when I posted that the engine is 50 HP. It's actually 115, and 20 years old.

If the power head is toast, you may be able to find a rebuilt power head. That is a popular size and would likely be a 90/115HP power head.

[Scubaseas]

If it's a F115 circa 2001 it does not have oil injection. Nor does it have a low oil cut out.

Remove plugs, take compression test if possible. Spray some pentrating oil in cylinders and see if it starts. It'll smoke quite a bit if it does. These are pretty tough motors. My staff at the dive shop tries their best to kill them. Just because there was no oil on the dip stick means it was at least 1.5 qts low. It holds about 5 qts. Compression test will tell you a lot about if you fried the rings or not.

When cranking over see if both cams are turning. When these motors run out of oil the cam shafts usually sieze. Ask me how I know this.

[MikeHoncho]

Originally Posted by gamayun

It was late night when I posted that the engine is 50 HP. It's actually 115, and 20 years old.

you are kind of all over the place which only results in guesses. What is the year and is it 2 or 4 stroke?

Here's my guess........20 years old = 2 stroke. "Checked oil before leaving" = auto injection. You didn't run it for 5 hours without oil but you did run it without oil probably which now requires a total rebuild. You may get it to start by putting oil into the cylinder. This is all irrelevant due to loss of compression and fried crank. Who wants to be in a boat dependent on a engine that siezed? Just stop trying to rule out that you know what happened and get a compression test done on it. If I was your mechanic and found out later that you didn't tell me you ran it out of oil, I would no longer be your mechanic.

[Finalee]

Tell the mechanic what happened. It will shorten the time to figure it out. I'm tearing down a diesel the ran low on oil. It started again but peace of mind is everything.