Locating a Blocked Cooling Passage

[IN2H2O]

Hey gang,

I recent purchased a 2008 232 (MR-1 HO motors) and during test drive I noticed the starboard motor was not getting much out the overboard pissers. The boat ran 10,000RPM and 45MPH for a quick test before I realized the starboard motor was not pissing overboard ?. Only ran for a minute or 2, overheat did not come on so hope I'm safe but going to compression test tomorrow. This evening I ran both motors on the hose at idle. The starboard motor did not have any water running out the #19 fitting and very very little coming out the #15. There was a lot of water coming out the pump intake screen and exhaust. Compared to the port motor running on the hose it had a lot coming the #15 fitting and very very little coming out the aft #19 fitting and none at all coming out the bow #19. (Bow #19 was pissing when on the water) Also had water coming out the exhaust and pump intake screen but not nearly as much as the seeming blocked starboard motor. I took a rag and blocked the #15 fitting on both motors and the port motor had more water come out the #19 fitting but the starboard again did not have any.

I confirmed the aft #19 to #15 fitters were not clogged by taking a air gun and blowing though the line. Both lines had the same air pressure exiting. I wanted to pull the #17 fitting but i could not locate it for the life of me but i feel like. Any advise on what else I can check to locate a clog? Anyone know why no water came out the #19 pisser on the hose vs on the water? I ran on the hose at high pressure for several minutes and even at elevated idle RPM's for 30 seconds or so with out luck

 

[WREKS]

Unless you are at high rpms, 19 does not stream. If you are not overheating, I would not worry. 15 let's you know the t-stat is open. Where it clogs is where you easily cannot go. That is the cylinder water jackets. Take temperature readings below exhaust manifolds near cylinders.If it clogs in cylinder water jackets, flushing will probably not help. Once I flush after an outing, I do not run on hose anymore. That leads to bio-fouling. These engines have to dry out. Do that by running without hose water for about a minute every week or so to dry out the cooling water passages!

 

[Scottintexas]

You should watch video in our faq about "how coolong wAter flows"

 

[WREKS]

The forward 19 is for higher RPMS. The stern 19 is for t-stat.

 

[IN2H2O]

The forward 19 is for higher RPMS. The stern 19 is for t-stat.

Would it be concerning to see the forward 19 flow water only out of one engine? Same with rear 19? Seems like all the water goes out the back for the starboard motor where the port pushes water out both (Bow and Stern) 19 fittings.

 

[Dfred]

This could get complicated.... but a good start is installing the “should be OEM” emergency tow/raw-water intake shut-off valves. Then 100% of your flush, salt-away and what you need to stay in the cooling system stays and runs through the engine, and not dump mostly back out the intake.
As noted- The system mostly gravity drains also, so if you keep the valve closed after flushing with salt-away (or whatever to break down the clog/deposits), the solution stays up in the system (but probably don’t want to leave an acid solution in for very long).... and of course (super on point @WREKS) once it’s operating normally - always finish with open valves and run dry the engines
There are tons of tips on checking and clearing the check-valves, T-stat and other problem areas. @CrankyGypsy is a guru.

 

[WREKS]

@IN2H2O If cooling system is working properly. a little water streams out rear pilots at low rpms. At high rpms some water streams out all pilots. The overheat sensors really tell what is happening. If they trigger, there is a problem. If not I would not be concerned.

 

[WREKS]

@Dfred One problem with tow valves is that if cooling system gets over pressurized, there is the possibility of pushing cooling water/steam into the cylinder/s. This could happen especially if engine is already running hot in some area due to an internal clog or some other reason.

 

[IN2H2O]

@IN2H2O If cooling system is working properly. a little water streams out rear pilots at low rpms. At high rpms some water streams out all pilots. The overheat sensors really tell what is happening. If they trigger, there is a problem. If not I would not be concerned.

It sounds like I have an issue since I'm not getting water out the #19 pissers and very little out the #15 pisser on one motor. The motor that's not pissing also has the engine/temp/oil lights out on the tach, however, boat is allowing well over 3K RPM. My question would then be can the overheat sensor be faulty and not trigger? Pardon me for being skeptical that its ok as I don't want to risk running a motor on a boat I just purchased and have no history with. I'm trying to wrap my head around why 2 motors at the same RPM with the same water routings as one not using the overboard bypass fittings.

Thanks for the assistance

 

[Babin Farms]

Have you verified that the hose is not plugged, even partially? I've had mud daubers plug even smaller lines that that out my outboards before.

 

[IN2H2O]

Have you verified that the hose is not plugged, even partially? I've had mud daubers plug even smaller lines that that out my outboards before.

I have checked the rear lines between fitting #19 to #15 and it is clear. I have not yet checked the forward betwen the exhaust water jacket and the forward #19 fitting but I plan to.

 

[WREKS]

It sounds like I have an issue since I'm not getting water out the #19 pissers and very little out the #15 pisser on one motor. The motor that's not pissing also has the engine/temp/oil lights out on the tach, however, boat is allowing well over 3K RPM. My question would then be can the overheat sensor be faulty and not trigger? Pardon me for being skeptical that its ok as I don't want to risk running a motor on a boat I just purchased and have no history with. I'm trying to wrap my head around why 2 motors at the same RPM with the same water routings as one not using the overboard bypass fittings.

Thanks for the assistance

Glad you mentioned that. There is the Engine Thermoswitch and the Exhaust Thermoswitch. Those two reduce engine rpms if there is an engine overheat. However, they can be disconnected and the engine will still run but you will not know if or not it is overheating. Three lights should always be flashing during No-Wake mode, unless they have been disconnected.

 

[Scottintexas]

i would also mention buying a YDS unit to monitor you engine in real time,

also a infrared temp gun to get some spot readings on each engine to compare,



.

 

[buckbuck]

 

[buckbuck]

@IN2H2O
Since you have a 2008 I highly recommend you pull the Y fitting and make sure they don't have a manufacturing issue.
Is this a salt water boat?
Watch this video.

 

[WREKS]

@buckbuck Where on the engine is that 207 Spot temp in your first photo?

 

[WREKS]

@buckbuck Nevermind. I see it. That seems very hot. Was that taken during a high rpm run?

 

[buckbuck]

I had access to a Flir infrared camera from work. Took the boat out on some 9,999 rpm runs to get it as hot as I could to use as a bench mark. Ran it hard and just shut it down and opened the hatch to take pictures. Typically I run at around 7500 rpm for a minute to cool things down before shutting off. Love my bullet proof MR-1 engines.

 

[WREKS]

Thanks for that info. Did you get readings on the exhaust manifolds?

 

[buckbuck]

Exhaust never manifested itself as a potential problem. It was always the block near cylinders 1 and 3. You can actual shoot the oil filter and get a pretty accurate reading. Was always close to what the YDS was recording.