mechanics fault or bad luck

[gitto]

brought a boat early this year with a 40 hp merc , 2000 model. it has oil injected. i put it in for a major service last week ,anyway took it out for its first run on the weekend and it went good for 20min then cut out , went another 100mtrs and it cut out again done this 4 times then i realized it wasn't using any oil. i was wondering if when you get a major service do they check the oil pump and filter and if they do ,do you need to prime it before use. seem strange i have never had any problem before and the day i get it back something goes wrong. the motor is still running ok i put oil straight in the tank to get me home. do these motors have a safety device that's stops the motor or was i lucky . i'm just after some advise before i ring the mechanic any help would be appreciated

thank you. gitto

[FNQCairns]

Hi gitto, almost universally the most dangerous time (for your wallet) is the first run after a service.
How do you know it was not using oil? 20min is not a long time and how did it perform after you premixed? also when you say cutout what do you mean?

Usually an engine that is running without oil will start to bog down or surge as the friction becomes too much for the engines output to overcome at any throttle setting..until it seizes.

My 'at desk' appraisal for what it is worth, is not oil starvation although anything is possible...more info.

cheers fnq

[fishingrod]

as above, 20mins is not a long time to work out if its using oil. I know some motors have a very narrow neck on the oil bottle, so maybe you can tell. You know your motor better than me.

Putting oil into the tank was probably a good move either way.

It could have been your breather (portable tank?) was closed and it was sucking it?
When you put the oil in it released the vacumn and ran ok?
Just a guess.

Get the mechanic to give it a diagnosis and check the compressions.

[DaMaGe]

I had an oil injection system, and would prime the bulb, along with the fuel bulb each time I started it.

The oil primer bulb was and is always very very tight, if ever it was loose I would consider not even starting my engine.

I have just recently organised for the oil injection system to be removed and instead will pre-mix fuel/oil to ensure if ever the pump did fail, or the oil injection became blocked that I am safer by pre-mixing.

[BaysideMarine]

Why would you do that??

Modern oil injecton systems are very reliable and to have one removed is a little backward thinking..

Bit like asking the mechanic to take the EFI unit off your vehicle and installing a carby instead.

I would seriously reconsider.

If it makes you feel more comfortable then run your main fuel tank on a 100:1 fuel/oil mix. That way if the injection fails the chances of destroying the engine are very low.

Cheers

[Kerry]

Anybody who doesn't want oil injection then why buy an oil injected motor in the first place just to take it off?

[DaMaGe]

BM, I believe the advice has been given to me by 2 mechanics and many readers of these forums. The oil injection system is somewhat 10years old and my engine is going through a rebuild. Did the oil injection cause this need for a rebuild; I don't think we will exactly know. I hope my backward thinking will allow me to control the oil consumption; this may save my engine for a further rebuild, or simply allow me to start the engine when the wind picks up instead of cleaning fowled spark plugs.

The 100:/1 is a good thought on top of the oil injection system, but again it has come recommended to me as of the age, and because it's OMC/Johnson then I am better off mixing my own fuel, as the pump is defiantly an issue.

[BaysideMarine]

Damage,

that sounds like the usual stuff trotted out by many a mechanic that doesn't trust this "new fangled" oil injection.

10 yrs od makes it 1996 and the VRO2 is a good unit.

Since 1985 the VRO was linked with a warning system that works well AS LONG AS ITS CHECKED AND MAINTAINED.

How many mechanics actually change the filter screen in the oil bottle when servicing??? Ask your mechanic next time what oil bottle servicing he does (don't tip him off by saying filter screen, just ask the question about oil bottle servicing). I know I do........

The filters are cheap, but they do get clogged with gel'd oil.....

If I had a 96 OMC engine I would ensure the warning systems worked (very very easy to check) and carry on happily. If I was really anal about it I would run 100:1 in the tank and drive happily

By the way, the reason most mechanics want to remove oil injection systems PARTICULARLY after a rebuild is to save the liability of IF the system failed for some reason. Safeguarding their own interests period. There is NO other reason. And I am a mechanic and rebuilder. I do not follow that convention however. I test oil injection units, test the warning systems and then make sure people understand the system operation and the associated warnings. If you TUNE a customer into THEIR ENGINE then it goes a long way to alleviating problems down the line.

By the way, what are the details pertaining to your engine rebuild? Oil failure is detectable by examinimg the pistons and the bores. And of course upon rebuilding and test running the VRO can be assessed at that point and go-no go determined.

So for a mechaninc to state they cannot work out what caused the failure is a failure of the mechanic to really understand the engines operation.

There are lots of marine mechanics but not so many really good ones......

Cheers

[Kerry]

Now that's one thing that VRO or really any oil injection never really did like and that was inferior oil! What oil have you been using.

As no oil injection works exactly the same running oil in the main tanks is always a smart thing to do anyway and especially on those bad days

Regards, Kerry.

[TonyOW31]

If you run too much oil in the tank you might end up with your mixture being too lean, if it was a permanent arrangement it would be worth checking the mixture and jetting to suit.
Just to clarify, I am talking about air/fuel ratios, not fuel/oil ratios.

[Squiggle]

Back on topic.......

Why was the engine running worse when you got it back from a major service than when you took it in???
You took the engine in with no vices you get back engine with vices?
Imagine taking a car in for it's regular service/tune up only to be driving it back and have it keep stalling on you.

Before you take it back to mechanic I would be making sure there is no charge for this, after all the motor was fine when you took it to him.