115 EFI 4-stroke ran with no oil, now alarm sounds

[twirk]

Hi There iBoaters,
I just bought a Mariner 4-stroke 115hp EFI from a guy who ran the engine without oil until it shut off and didnt dare use it any longer. The guy got stuck in bad weather and had to ignore the alarm until he could get close to port and be towed home.

Oil is now refilled and the engine starts no problem, however the alarm sounds when revving the engine (i dont remember if it beeps or if it is constant).

What would cause this and what is the solution?

Does the mariner 115 EFI have a an automatic shutoff when it runs out of oil, or is there a chance there was a meltdown somewhere?

 

[BoatNoobie]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

how did it run out of oil? if there was no oil and the motor was running. that motor is toast.

 

[twirk]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

Well, the previous owner forgot to put oil in the engine and went out sailing. He got caught in bad weather out on the sea when the oil alarm began to go off. So he had no choice but to sail back towards home even though the alarm was going off because the oil was low. About a kilometer before he reached the dock the motor shut down, and he got towed the rest of the way.

Later, he refilled the oil and started the engine. It started, and it will still start. Ive witnessed it several times.

So it's not like the piston rings melted down and made the engine stick, because it turns over fine and will run. We have only tried using the engine at low RPMs, which causes the alarm to sound (although i dont remember whether it is beeping or a constant sound).

What would suggest that i check in order to make sure the engine is "toast"?

 

[Outsider]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

Were I either of you guys, I'd start by determining what the alarms are for ...

 

[Timestep]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

The oil may be a red herring. It could easily be overheat due to a stuck thermostat or poor impellor? Get a Mercury diagnostic check and all will be revealed, or maybe not?

Regards

Dave

 

[twirk]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

The previous owner said that the engine definately ran out of oil that once, because he checked the dipstick and it was dry.

As I understand it, the alarm is for overheating (constant sound) and low oil (beeping). Is that correct?

I will check around to see if it possible for me to get a merc/mariner diagnostic check. I am not optimistic though. I live way the heck far out in no mans land

Is it possible that the piston rings have expanded but still allow the engine to run?

Does anyone know whether the Mariner engine has an auto-off when it detects extremely low oil levels?

 

[j_martin]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

It is possible for a 4 cycle engine to run with just a few ounces of oil in it and not be seriously damaged. I have teenagers, and have seen it twice so far. Modern synthetic oils have so much film strength that they can protect bearing surfaces without oil pressure, at least for a short time.

To be hearing an alarm without knowing or even remembering the beep code heard, and making assumptions about what it might be is going beyond ignorance. It's just plain stupid.

At a minimum get the maintenance manual, understand the alarm system, and debug the problem to it's actual cause. Like Outsider said, at least learn what the alarm is for.

hope it helps
John

 

[Faztbullet]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

I hope ya got it cheeeep!!! The reason alarm sounds is oil pressure is low and running with out oil will damage bearings,crank,cam and head..

 

[Timestep]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

Still could be overheat, no evidence to the contrary!!

Dave

 

[twirk]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

I did get it cheap

Good to hear that youve had experience with engines surviving running without oil. Perhaps there were still a few ounces of oil when the engine shut off on the engine. Ill check to see if he used synthetic oil.

Ive now read over the manual and the reason why the alarm/buzzer sounds is either overheating or low oil pressure. And it seems the engine has an automatic shut-off (power-off) if it overheats or oil pressure drops. This is hopeful for me, because perhaps the engine shut off before too much damage happened.

I have the engine in a workshop right now and will try to see if there are any Mariner/Mercury mechanics in town who can diagnose it.

Also i will try to run the engine briefly to identify the buzzer/alarm pattern.

 

[twirk]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

I hope ya got it cheeeep!!! The reason alarm sounds is oil pressure is low and running with out oil will damage bearings,crank,cam and head..

Faztbullet, do you see this damage occuring in all cases where an engine runs low on oil, even with the Mariner auto power-off feature.

Like, should I assume that I will HAVE to replace, bearings, crank, cam and head?

 

[Faztbullet]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

That engine is the Yamaha badged as a Merc and no auto off mode(safety feature). Its will be real easy to test,change oil and filter,refill crankcase,remove oil pressure switch and install a oil pressure guage 100psi max. Start engine and let warm up and check oil pressure ,it should be 50 psi at idle +/- 5 psi for wear/guage inaccurate's. If below 40 psi internal damage has occured no matter what type of oil or the level of oil. Cut open the old filter and check for babbit material in filter pleats. The oil protection and temp overheat mode/alarm will put engine in a limp mode but will not cause it to shut down, only thing to cause this would be a siezure. Test compression as oil /compression rings may have have caused it to stop. I have repaired quit a few of these do to oil problems and most common damage is cam bearings as they are nearly last to get oil...

 

[Silvertip]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

The alarm is probably not a "low oil" alarm but rather an "oil pressure" alarm. Four stroke engines have rod and main bearings that are lubricated under pressure from an oil pump. If the engine runs out of oil the pump can't obviously deliver any oil and the bearings run dry. Even if the engine is full of oil, the bearings may have been damaged or spun and the oil PRESSURE is now lower or zero -- hence the alarm. An oil pressure check with an analog gauge is necessary.

 

[Timestep]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

"Like, should I assume that I will HAVE to replace, bearings, crank, cam and head?"

Not if it's a water problem?

Dave

 

[Faztbullet]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

Test first and that will tell ya real quick what it needs....

 

[Dave1027]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

How did the sailor forget to put oil in it? Was it a brand new engine that did not come with any oil? This story sounds a little screwy

 

[twirk]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

Yes unfortunately it does sound like a screwy story and it also happens to be true :-S The sailor simply forgot to check for oil. The engine is approx. 4 years old (i think, i cant actually tell).

 

[j_martin]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

Is there a chance we're being punked again?

 

[twirk]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

That engine is the Yamaha badged as a Merc and no auto off mode(safety feature).

You say this model is actually a Yamaha? I have a Yamaha f100 4-stroke in storage (I believe it is a 1999 or 2000 model). If it turns out i need to exchange the camshaft bearings in my Mariner, are these parts interchangeable? Meaning, can i use my yamaha f100 parts on the mariner 115 EFI?

Ive been looking at diagrams of both engines and they are practically identical.


@j_martin: Punked? I am not sure I follow?

 

[cr2k]

Re: 115 EFI 4-stroke ran with no oil, now alarm sounds

Not sure if this is right on your engine, but some overheat sensors just melt into the engine and ground out to set the alarm off. In this case the rubber grommet needs to be replaced.