Motor Problems

[stinger160]

I have a 2006 mercury, 25 horsepower four stroke. Every once in awhile when cruising at 5000 - 5500 rpms, I get the warning alarm, engine slows to an idle. I can turn it off then back on and it runs fine. Took it to a local mercury dealer, put a new oil pressure sensor in. Still doing the same thing, periodic alarm warning etc. took it back to dealer, checked for engine codes, didn't find any and couldn't get the engine to replicate the problem. Charged me $60 and said they didn't know what to do.

Any ideas?

Thanks for any help you can provide.

[fishinwrench]

Did they run it on a hose, in a test tank, or actually launch your boat and take it for a ride ?

Since it fires back up immediately with no warning horn or power loss I'll assume it isn't an overheat issue.

Did they actually test for adequate oil pressure @ WOT or just swap the sensor ?

The sensor may be doing its job !

I haven't ran into any oil pressure issues yet but I do know that the 25 is equipped with an oil pressure regulator above the sump on the return side which if partially blocked will REDUCE oil pressure at the sensor port.

The actual oil pressure (psi) isn't very much (like 6psi or something like that) so it stands to reason that the sensor would be extremely sensitive.

Is the oil level where it is supposed to be on the dipstick ? Some folks fill it to the very top of the crosshatch.....it should be slightly below the extreme top of the crosshatch when cold and the motor in a straight up/down position.

[stinger160]

I regularly check the oil but will confirm if it is below the crosshatch. Ran it in a test tank, never took it for a ride. Not sure if they tested for adequate oil pressure. Is there a particular way that they can check the actual oil pressure that I should ask them to test?

[fishinwrench]

Yes there is, but just like many other 4-stroke outboard issues there is no need discussing it because IF there is an oil pressure problem nobody is going to be willing to pay what it will cost to fix it properly.

Trust me, once you hear the estimate you'll simply decide to snip the horn leads, run her til she blows and then scrap it.

If you have by chance followed any of my original 4-stroke rants on here and wondered why I spoke so badly about them....maybe now you understand.

You have gotten 8 good years out of it, and you'll probably be able to limp it through a couple more. That's better than a lot of them for sure.

Don't get sucked into a thousand+ dollar cobble-job on a over-engineered little 25hp.

[stinger160]

That's about where I was going. Run it like crazy until it blows! Then get me a new boat.

[Fish24/7]

Might want to take it to another shop for a second opinion.

All of our certified mechanics say the majority of 4 stroke repairs they do are due to lack of maintenance by the owner/operator..

We have 9 Mercury 4-strokes all bought new in 2006 ranging from 60-115hp. Thre's 900+ hours on each of them, and they still perform flawlessly because they are being well maintained.

good luck

[REDSOXWSCHAMP]

maintenance is key.

[stinger160]

I annually change oil and check it every third trip or so, along with the other maintenance recommended in the manual.

Came to oaf to try and get some ideas before I went to another mechanic.

[fishinwrench]

Might want to take it to another shop for a second opinion.

All of our certified mechanics say the majority of 4 stroke repairs they do are due to lack of maintenance by the owner/operator..

We have 9 Mercury 4-strokes all bought new in 2006 ranging from 60-115hp. Thre's 900+ hours on each of them, and they still perform flawlessly because they are being well maintained.

good luck

A '06 with 900+hrs. is performing well because it is being USED REGULARLY, not because of perfect "by the book" maintainance.

Which maintenance step(s) do your certified techs claim is allegedly being skipped or not done properly?

[stinger160]

Found the problem. Warning was for overheating not oil pressure. Tracker marine in independence mo found that the thermostat was occasionally sticking shut, allowe the engine to exceed operating temp range causing the alarm to go off. New thermostat and running like a champ.

Not sure why the other service shops didn't understand the reason for the issue as overheating, I would have thought the computer would tell them.

Oh well, at least I'm back in business. Thanks to all that provided advice!