600SCI engine water Flow Issue
 

I am having low water flow in my port side Engine. it is thowing my smartcraft into guardian Mode. Engine temps, and everything seam ok. just the H20 flow. I tried to flush out the front Heat Seperator, but no dice. Could it use an impeller maybe? Any Advise would be great. I am dead in the water.

-Mike

Did you change the impeller and housing recently? Very important to change BOTH out a minimum of once a year on 525/600/700 to get maximum cooling and water flow. Buy spare sets and keep them on your boat. While your at it make sure you change fuel pump oil.

I replaced it two seasons ago. prob about 50hrs ago maybe. The engine isnt getting hot though? Could that still be the problem? I have a new impeller in my hand im going to install 2marro

50 hrs is way too long on 525/600/700, you risk running headers hot and springing leaks. The headers will run hot before the engine runs hot. If your headers have "golding" on them, they have run hot and need to be pressure checked. You should pressure check them anyways as maintenance. As said before don't just do the impeller, you must do complete impeller and housing a minimum of once a season. The impeller/housing assembly "mates" together and only replacing one will not get you 100% performance from the parts. Don't forget fuel pump oil change too.

Thanks for the info. I will start making this a yearly routine. Do you think its why I lost H20 pressure?

This is the kit I got.

https://www.marineengine.com/newpart...ER46-807151A14

Just be sure to buy genuine Mercury Impeller/Housing kits, you can order from any vendor out there. Schematics make it easy to look up parts in the future like at Bam Marine. Watch some YouTube videos on the actual install, you do not want to dry start the new impeller/housing the first time. Just do not use Vaseline. Dishwash soap very lightly or even a VERY light coat of water proof grease. There is water pressure and there is water flow. Both can certainly be affected by a bad impeller/housing. Make sure when you disassemble for service that all the "veins" are attached to the old impeller. If not you will need to back flush the system.

we have had the same issue with a 600 set up , sensor is known for failure and throws it into guardian also . swap the sensor and we are good for a season .

^^^ This is another trouble spot, verify with your Rinda Scan Tool that you purchased because you want to maintain your 600 SCI to the best of your ability, right?

Which sensor is this? Where is it located?

Great advise thank you. Im going to change the Mercury Impeller/Housing while the boat is in the water. I always use dishsoap to lubricate it. I dont really think its a sensor cause when you start the boat you can noticably see that the one engine is not movine as much water. Also the port engine is not in sync with RPM's with right side motor when I give it a little throttle.

I dont have said Rinda Scan tool. Where do I find one of these?

I was busting your chops. Rinda scan tools prove invaluable to diagnose and check functions. Owning Merc race engines its a must have to avoid down time. Think of it as an OBD 2 scan tool for the water. http://www.rinda.com/techmatepro/

I may have to scoop one of these. Any pricing on them? Can i get a used on cheap.. Looks like it does the same thing my smart craft is already doing..

Also did you read about my RPM's not being in sync. Is that something that could be caused by impeller as well?

Ttt

If you have repeatedly put the motor into Guardian, it may now be at a reduced % power level until the codes are cleared from the ECM and it shows 100% power available on the scan tool.

Be careful with relying on temp and pressure gauges to indicate water flow. When mine got plugged up there was no indication of a problem on the water temp or pressure gauges.

there are numerous issues with this, there is a re-route on the intercooler cooling with a upgrade from whipple, my suggestion would be call them and see what they have come up with on this, have friends that have the same issues with these engines

I did the water re-route from whipple. Made a huge difference in the headers keeping colder. Im going to guess this is the Impeller, and ill have it changed today. I will update with results

Do you know if once the water flow problem is fixed the ECM will clear itself of the codes, or do you have to have the scanner

Ok so I put a new impeller assembly in. We flushed out all the water lines, and we are still getting low H20 on the engine. Can somebody inform me on where the H20 sensor is located so I can swap them from engine to engine to see if that's the problem? Thanks

The sensor is at the left rear of the engine on top of the engine oil cooler, they get plugged with hard water I have had to replace mine twice.

pull the oil cooler off and make sure it's not clogged in any way, seen all kinds of crap stuck there

Ok this is my next step then

I will flush the rear oil cooler with a hose and see what comes out. Then I will switch the sensors from the engines to see if one is bad

You need to be able to look through the cooler holes to confirm there are no small stones, wood chips, etc lodged in the holes. Water will generally not work for proper flushing. ...either remove the cooler or do this while mounted. I use a piece of straightened coat hanger (or welding rod) to push pebbles out. A few times, I've had to remove the cooler and use quite a bit of force to get the stones or wood chips out - due to the location of the coolers on my 575's - they are a b!tch to get to.

On more than a few Bajas, I have seen issues with the fresh water flush system getting gummed up with debris and causing water flow/pressure issues.
There is a spring loaded ball check valve in the Tee into the seawater side of the system. Remove your "T" fittings and pull this ball out of there. It's not needed.
This may or may not be your issue; but it could be an issue in the future too.

Also, I get a little spooked on switching sensors like this from motor to motor. I get the troubleshooting aspect of this, and ease to pinpoint problems. I myself have done this at times. But when it comes to sensors that screw into blocks and other parts, you never know when one is going to go sideways on you, and snap off or worse. It may be worth your while to just replace the sensor, vs. trying to swap them.

I bought a new sensor. im going to just replace it. looking at pictures it looks like this rear oil cooler is a ***** to get to!! Any advise?

http://i47.photobucket.com/albums/f1...0303-WA010.jpg

http://i47.photobucket.com/albums/f1...0303-WA012.jpg

I made these just as guildlines for me tonight when im laying over the engine.

Any chance you have a picture of where this T fitting is?

flushing may not work, had one a while back that was full of tiny rocks embedded in the screen that would not flush out, had to be poked out with wire..

I guess I will try flushing it first. I don't know whats involved with removal

Follow your Fresh Water Flush (garden hose) connection hose as it heads toward your SWP. It will be in the line 1 1/4" hose from the transom assembly to the SWP. IF you have Sea Strainers, it will likely be between the transom assembly and sea strainer.

I put the new h20 sensor and flushed the oil cooler and the engine still is blocked and getting half the psi as the other.. The only thing I haven't done is cleaned my sea strainers out.. Could that be the issue? Also I could try what you said sydway

Yes, the sea strainers would have been the first thing I checked.

For real?????
Start simple, go from there. If you have sea strainers, you shouldn't have debris in the oil cooler unless you've lost an impeller.
also make sure you don't have a kinked hose anywhere in the system. Good luck!
.

I haven't cleaned them cause they are so hard to reach. Can they be cleaned while the boat is in the water?

They should be setup with shutoff valves so they can be cleaned in the water.

There are no shutoff valves. How hard will the water be pumping into the boat? Can I just open it quickly, and flush it out. Put it right back together? They are Livorsi strainers with the wing nut fasteners

Put something over your water pickups on the drives. You will get water coming in pretty quickly when you take the lids off. You can take a outdoor caliber garbage bag and put it over your water pickups on the drives individually which will limit your water coming through with the lids off.

Are you certain you do not have any debris in your drive's water pickups? You could even have zebra muscles or other growth in there as well.

Yes im possitive the drives are not the issue. So you are saying to bring my drives up all the way and put havy duty bags over them to limit the water from coming in the strainer. Hmm.. wouldnt the bag take in water when you try to put it over it. would I cover the whole drive, and prop with the bag?

You just need to find a way to close off the water intakes. If you put a large bag over the whole drive, and tie the handles at the top, there is only so much water that's going to come in the strainers. With fresh water, this is no big deal. You could also tape over the intake holes if you can find something that will stick underwater.

Do you leave this boat in the water all the time? That's not something I would do.