Flushing the Crap Out 250 Pro XS

[Rude Awakening]

I'm a long time Evinrude fan. Yesterday I picked up my first new Mercury. A 250 Pro XS. I made a photo copy of the break-in page from my owners manual and headed for the lake. I beached the boat next to the ramp, parked the truck, and headed out. About halfway through my second rpm change I got on overtemp alert on the SC gages. Gack! A quick shut down. Let it cool and called the mechanic at the shop.

While I was trying to get through I turned the key back on and checked. The engine temp was only 113, but the alarm started sounding again. Finally got through to the mechanic and he said to check the pee hole. It was probably plugged and the over temp was probably the compressor, not the engine.

I idled over to a dock where I could tie up the boat to get to the back of the motor after the temp alarm stopped, and cleared the pee hole. Yep it had sand in it. A little wiggling around and it started peeing normally. Never had the temp go off again the rest of the trip. I took plenty of time to warm the motor up again, and then proceeded to make a ten mile run to get some more breakin time on the clock. At varying RPMs (every two minutes by the book) the engine temp held steady at 102 the whole time out and back. Water temp was around 62-64 degrees where I was at, and air temp was in the low 70s. Given the pee hole was plugged up does that mean the stats are probably stuck open also? Is there an easy way to check/flush/clear them? I suspect if they are stuck open just running it on the flush adaptor may not be enough to clear them. I'm in Winterhaven Ca, and its quite a drive to take the boat to a shop. 3+ hours in any direction one way.

One thing the mechanic said yesterday was, "Mercury says don't run them in dirty water." You are kidding me right? New Mercurys can't run in 75% of the water in the country and 100% of the water near where I live?

Sincerely,
Rude Awakening

[EuropeanAM]

Welcome to BBC!

In regards to your compressor overheat- you're likely fine now. The telltale fitting is indeed the "outlet" for this particular cooling circuit (and if it's plugged, the compressor will overheat).

Running the engine on the flush attachment AT IDLE SPEED ONLY may assist in washing sand or debris from the system. That's really it's ONLY "useful" purpose.

Your technican was indeed correct.... the cooling system on a marine engine is meant to be cooled by relatively clean circulating water (and not mud, sand, wood chips or debris). Probably not what you want to hear.... but he's definitely correct.

Probably occurred when you "beached" the boat.... some additional engine trim angle when approaching shallow water may be a viable solution to prevent future problems.

[Rude Awakening]

So according to you, him and Mercury 75% of all inland marine users should avoid Mercury. Got it. You really think the flush adaptor will get all the crud out or do I need to pull the stat housings?

Additional trim angle huh? LOL. I've been running Evinrudes since the 70s. Just my first Mercury. I've still got my first "hot" rude on a stand in the garage. A 235 from the early 80s. Sorry getting to old to remember which year model without going out and looking.

[Flipping57]

From what you have said on here so far I would say that YOU should avoid Mercury at all cost.

[Bob La Londe]

I always thought it was odd that stuff that would make it through the entire system would plug in the water outlet port. On these Mecurys (I have one too) there is a sharp turn in the pee hole fitting that seems to be the cause. If it was straight I bet all that stuff would blow right through.

From what you say, yes you need to pull both thermostats, and heat them up on a pan of 130-140 degree water and swish them around to clear out all the debris.

Get used to it. I just had the same thing happen. Picked up my motor from the shop with a new powerhead and get an overtemp from the outlet plugging up.

Winterhaven huh? I bet we were both adrift on the river at the same time. LOL. One thing my mechanic suggested is to drill the outlet port out slightly to round that internal corner. Not sure I want to do that, but I can't see the harm.

[redline]

First, ALL marine engines are suspect to some sort of "clog" if the debris is concentrated enough in certain areas. The newer Mercs have such a sophisticated on-board PCM that the operating parameters are "close" enough to warn you of potential damage before it occurs. No system is foolproof, but this one is close. I agree with a slight tell-tale mod. Drill it our slightly to allow the rocks you've picked up to be expelled.
As far as that "hot" 235.....well, they weren't so hot performance wise, but they sure had a beautiful harmonic imbalance that would shear a flywheel key off and start chirping like a bird! Stock for stock a 2.4 / 200 Merc SMOKED them on a hi-perf hull.....the only way those things ran was with an even-firing crank, light flywheel and balanced.....be happy, you've got a great NEW motor.... Oh...and I can't resist.....if 'ya don't like the Merc maybe you ought to prep that old "RUDE FOR AN AWAKENING"!!!! Don't worry, it'll blow up...


Modified by redline at 7:42 PM 3/4/2010

[Bob La Londe]

Almost forgot... When I talked to my mechanic about it he said he had a whole bunch of guys at a tournament with the exact same problem. He went so far as to say that the Mercs where the only ones who had it. Kinda surprsied me to hear that from a Merc mechanic. I will probably keep using this guy. Its nice to hear unedited honesty from a mechanic like that.

Maybe they were just the only ones to alert you to the problem? LOL. Time will tell.

[JRBjr]

The sharp turn in the pee hole fitting will hold water and freeze, it cost me a tournament this winter because at the blast off, I was getting no water pressure because the water had frozen in the line. The mechanic said it was at the bend where the water could not drain. I was wondering if I could shoot a burst of air through it and clear it out after I fished the day before to keep it from freezing in the line. All I would need is a can of compressed air like they make to blow off computer equipment.

[John Jackson]

I think we are missing one thing here. The sportsmaster and torquemaster both have water intakes under the bullet of the lower unit. This allows the motors to be run higher and still live, where other motors would burn up from no water. However, it also means if you hit the bottom, you can pick up debris. I suspect you picked up trash when the bullet nose contacted the bottom.

[Bob La Londe]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JRBjr &raquo;</TD></TR><TR><TD CLASS="quote">The sharp turn in the pee hole fitting will hold water and freeze, it cost me a tournament this winter because at the blast off, I was getting no water pressure because the water had frozen in the line. The mechanic said it was at the bend where the water could not drain. I was wondering if I could shoot a burst of air through it and clear it out after I fished the day before to keep it from freezing in the line. All I would need is a can of compressed air like they make to blow off computer equipment. </TD></TR></TABLE>

Hmmm.. how about a tiny blast of WD 40 in the hole? The WD stands for water displacer after all. Problem is WD also holds dust. Down here in the desert where I live that could be a problem. Of course I usually don't have problems with freezing. (it does freeze in the desert, just not that often)

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by John Jackson &raquo;</TD></TR><TR><TD CLASS="quote">I think we are missing one thing here. The sportsmaster and torquemaster both have water intakes under the bullet of the lower unit. This allows the motors to be run higher and still live, where other motors would burn up from no water. However, it also means if you hit the bottom, you can pick up debris. I suspect you picked up trash when the bullet nose contacted the bottom.</TD></TR></TABLE>

There's the point! <U>With low water pickups, if the gearcase nose comes into contact with the lake bottom.... You're gonna suck up debris</U>.

Btw... Rude Awakening, you've apparently misunderstood the point, or feel like twisting words. I specifically referred to "all marine engines".... and not just Mercury. Doesn't matter what brand you've got.... what color it's painted, outboard-inboard-inboard/outboard or jet drive, or how big it is... pump it full of sand and it's gonna overheat.

We're here and willing to help those interested or looking to learn... unfortunately, there's "some things we just can't fix".

We try to keep this forum a "helpful" place.

[skeeter77346]

I currently run the 2007 250 ProXS (and Merc V6 motors since 1979) in So Louisiana and Texas lakes and bay systems. I spend a lot of time in marshy bay systems and routinely jump up in these shallow ponds. Z22 Shearwater bay boat. Amazing how well the Merc does in this stuff. Just my experience.
Once I did stick a 2005 250XS (Sporty LU) on a sand bar at low tide in Texas and had to remove and clean the thermostats at the dock - operator error in that case.

Good luck.

[Rude Awakening]

EAM, Not besmirching your knowledge or skills. I may get rid of the low water pickups. No longer have a need for speed anyway, and my current boat is a heavy weight. I may even plug up those low water pickups and just set the motor a tad deeper.

Other guy, that 235 was a race motor. I remember mine was the year before they came out with the 240 ST. What does that mean? I dunno, but it served me pretty well on my Hydrasport for almost ten years, and if I find the right boat to put it on I'll use it again. Maybe the Merc you mention was faster, but I can say in the 80s there wasn't much on the river that could pass me when I had the nerve to drive it past 3/4 throttle. I'm one of the guys who got to learn about huge holes in props to get boats into their power band on the holeshot. I finally had to go to 7/8 exhaust vents. LOL.

Bob, thanks for the tips. I reamed out the pee hole from both ends, and I pulled the stats. They had some pretty large pieces of gravel in them. How does stuff that big even get in the system? I guess if you hit it hard enough. LOL. Also, if you don't mind would you drop me a PM with the name for your wrench? Sounds like the kinda guy I want to give my business too.

P.S. I wish you had warned me about the paint on the gaskets. I tore one taking the stat housings off. Not a big deal though. A trip to Yuma for some gasket material and I was good to go. I'll try and get my breakin time done this weekend. Maybe I'll see you on the river? What are you running. If I see one I'll wave.

Sincerely,
Rude Awakening

[esdbass]

Don, Red, Jon: A side from what you guys pointed out would adding a Popit diverter also assist in keeping it from clogging the T Stats ?

Red and I had a heck of a PIA with some small debris that clogged the pee hole and that slight mod of it is helpful indeed

[Bob La Londe]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rude Awakening &raquo;</TD></TR><TR><TD CLASS="quote">Also, if you don't mind would you drop me a PM with the name for your wrench? Sounds like the kinda guy I want to give my business too.

P.S. I wish you had warned me about the paint on the gaskets. I tore one taking the stat housings off. Not a big deal though. A trip to Yuma for some gasket material and I was good to go. I'll try and get my breakin time done this weekend. Maybe I'll see you on the river? What are you running. If I see one I'll wave.

Sincerely,
Rude Awakening</TD></TR></TABLE>

Brent at Performance Marine in Glendale. So far I like him, but time will tell.

I never thought of mentioning it, but a scalpel or Exacto kife allows you to reach in and slit the paint in circumstances like that. Also a thin blade like a fillet knife allows you to reach in between the metal surface and the gasket if it still sticks at the edges a little bit.

Black Bass Cat Cougar FTD. I used to call her The Antique Kitten. From now on the bitch will be known as the BLACK CAT (subtitled Don't cross my path) due to the wonderful luck I've had. LOL. I may even label the motor Lucky 13 since it went in for a new powerhead at 13 hours. I've already got a logo in mind. LOL.

No need to wave. With three tournaments on the river this weekend keep both hands on the wheel.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by esdbass &raquo;</TD></TR><TR><TD CLASS="quote">Don, Red, Jon: A side from what you guys pointed out would adding a Popit diverter also assist in keeping it from clogging the T Stats ?
</TD></TR></TABLE>

Not really.... in order for the poppet diverter to change the scenario.... it would have to be dumping enough water to keep the thermostats from opening (which will create a MUCH BIGGER problem).

[esdbass]

OK Don, I re thought it a little. It kinda does dump a lot of water which can indeed be a problem about getting up to temp in cold water, hence a 1/2" restrictor

[redline]

The motor was a "2.6 XP", which was a "hot" 235, rated at 245HP. Squared off exhaust ports, plastic reeds, louvered cowl and slightly raised wot rpm range. They ran ok. Just kidding on your old motor, they were really good fishing engines, just don't live long at hi-rpm's........

[Bob La Londe]

As much as I hate adding electronics to engines why not change to a thermistor controlled solenoid for the t-stat. Or a solenoid assist to the t-stat so it can operate non-electronically unless there is a problem. The computer can then open the solenoid controlled passage wider for a few seconds any time the motor runs under a set temp for more than X minutes... allowing larger rocks to stick the stat open. LOL.

Seriously, there may be something there, but it is another level of complexity.

All copyright retained. LOL. Hey Mercury, if you use this idea I want a new motor of my choice for it.

For that matter, why isn't the computer giving us an alert to extended run times under temperature? How about limiting RPM until its warmed up too? Low temp running reduces fuel efficiency on other motors, why not outboards? And failing to warm up (pushing blame off to owners) is the cause many give for the piston siezures so many of us have experienced.

[EuropeanAM]

Your engine is equipped with an under-temp feature, that will set Engine Guardian, in the event that it fails to come up to operating temperature.

The fault is called "Thermostat Fault". For it to set the following conditions must be met:

-Cold engine start
-Engine idles (remains below 1200 RPM)
-Five minutes pass without the engine reaching target operating temperature

If all of the above are met (the owner is attempting to warm up the engine, and it simply will not come up to temp), Engine Guardian will kick in, limiting RPM's to a safe level (based upon the severity of the lack of temperature).

So the system is there.... but is often "over-ridden" by an "antsy operator" that hammers down without monitoring temp, or allowing time for proper warm-up.