2020 Mercury 250 Pro XS

[IdleTime]

Hi All,

May not be the correct form for this but want know what you think.

I have a 2020 Mercury 250 Pro XS four stroke with 38 hours on it. After our last trip in October I noticed the paint blistered on both left and right lower cowlings and the 5 inch extension on the lower unit discolored, the boat had been in the water for 20 day's, break-in had been completed earlier so ran it normally, still only full throttle and trim for not more than 5 minutes, temp/pressure always consistent. Took it to my local Mercury dealer, Mercury replaced all the parts under warranty. They had no idea what caused this but thought the unit may have been repainted??? Anyway scheduled with the dealer to replace the cowlings, 5 inch extension and while there, change the engine oil and lower unit service. Sounds simple right? After the motor sat overnight in my garage I notice a puddle of oil. It was engine oil that had spilled from the oil filter, into the cowling that made its way to the floor. I had done a lot of research on this engine before purchasing and Mercury could not have made it simpler to change the oil without causing this mess, with drain provisions provided on the side of the lower unit for the oil and a "catch" can with hose connection under the oil filter. I found the "catch" can was full of oil. I sent pictures to  the dealer and the technician that did the work called me saying he typically works on bigger projects and wasn't familiar with these new motors but apologized. He said he did leak check the filter, but if the catch can was full of oil what kind of leak check could he have accomplished, I asked? He replied that if the filter was leaking it would have sprayed all over the place.

Anyway, after dismissing that entire conversation I cleaned all the oil, hooked up the muffs to do my own leak check. Engine started right up, but after a couple of minutes the water temp went to 200 degrees (typical temp is around 137 in the water) so I shut it off, just as the steady warning horn sounded. I did have a week stream out "P" hole, so I thought water wasn't an issue. Some "online" research notes that these new motors will not run on muffs and require a tank.

Has anyone experienced the same "running on muffs" or paint issues described?

 

Also For Sale - 2020 Minn-Kota Ultrex, I-piolt, 60" shaft, 36V, US2, with quick release bracket for $2100.00 and listed in For Sale form.

 

A couple of pictures of the new rig(May 2020), Ranger 620 FS, If you see us out on the water stop and say hey.

[fishinwrench]

If it has the additional water pick-up vent on the nose cone then you can cover that vent with a piece of duct tape and run the engine on muffs.  But....if you ran it (without it covered) until the warning horn went off, then you're gonna need to replace the water pump, pronto.  

If I understand correctly, you said the boat was in the water for 20 days (?) .     If so, then electrolysis from a badly wired (improperly grounded) dock could have caused the paint blistering. 

FYI:. That overheat is going to store a code on the ECM.....So congratulations, your warranty is null and void.  😂

[snagged in outlet 3]

22 minutes ago, fishinwrench said:

FYI:. That overheat is going to store a code on the ECM.....So congratulations, your warranty is null and void.  😂

OUCH!!

[fishinwrench]

26 minutes ago, snagged in outlet 3 said:

OUCH!!

Yeah, Ouch! 

Had it been a 2-stroke.....No biggie.  Let her cool off and you'll never know.

But a 4-stroke has a number of little plastic do-dads (valve guides, valve seats, ect.) inside the powerhead that don't react well to getting hot.   Get her hot ONCE and it'll never run the same again.  Those parts are plastic because y'all want QUIET motors.   They'd sound like a diesel if it was all hard metal. It would sound like a vibrating tin can with 20 penny's in it.  They would probably run forever....but nobody would buy a motor that sounded like that when it was running.

Is all of my 4-stroke ranting beginning to make any sense yet? 🙄

[IdleTime]

Now this is not the kind of thoughts I was looking for but helpful. 

The manual say's "Engine Guardian System monitors the critical sensors of the engine for any early indication of problems", so doesn't make sense to provide a "warning" horn if, when it alerts it is too late. I was watching the temp gauge as it climbed slowly and was going to shut it off at 200, when it hit 200 the horn sounded and I shut it off. Will check with the dealer and let you know what they say.

If it is toast, anyone want to buy a boat?

 

[snagged in outlet 3]

24 minutes ago, IdleTime said:

Now this is not the kind of thoughts I was looking for but helpful. 

The manual say's "Engine Guardian System monitors the critical sensors of the engine for any early indication of problems", so doesn't make sense to provide a "warning" horn if, when it alerts it is too late. I was watching the temp gauge as it climbed slowly and was going to shut it off at 200, when it hit 200 the horn sounded and I shut it off. Will check with the dealer and let you know what they say.

If it is toast, anyone want to buy a boat?

 

I hope it turns out ok for you.  

[dtrs5kprs]

Things like this make me love my old '05 250 more and more.

[fishinwrench]

Oh it shouldn't be "toast" if you shut it off as soon as the horn went off.  But the friction from starving the water pump of sufficient water will damage the impeller. 

 But still, I wouldn't freely offer up the information that it overheated while you were running it on a hose. Just for your own sake.

Although anyone trained in deciphering the ECM data is going to see that it was started, and then immediately began to overheat at idle speed.   Gonna be pretty obvious that you did something that was specifically "not recommended".  They'll make a note of that and it can effect any future warranty claims.  

[IdleTime]

Called the Mercury dealer to talk about the temp issue. He responded as wrench did that there are low water pickups on the leading edge of the lower unit that must be covered when running this motor on muffs. He said there is a boot you can purchase or use tape to cover the holes. For damage, he asked if there was water coming from the "water pump indicator hole", if there was then the impeller should be ok and didn't run dry, but suggested to back it into some water and monitor the temp to insure no impeller damage.

He said this event will not impact the warranty but suggested that the next time the boat is in for service to have them clear the code, as we know the reason for the onetime code.

Lessons learned: 

Make sure to cover the low water pickups when running on muffs.

Make sure water coming from the "water pump indicator hole" right after starting the engine.

Monitor water pressure and temp at all times if so equipped.

Hope this helps others not make the same mistake.

[fishinwrench]

The fault code will clear itself after 3 run cycles with no repeat.   But it will always remain in the run history. 

Assuming that there was enough water circulating to keep friction from distorting the sealing ring edges of the impeller is a bit of a gamble.   

100.00 could potentially save 7,000.00