2008 185 Sport - Temp Alarm?

[Lazy Daze]

Ah, perfect! That picture matches up with Mark's description. Thanks, Ron!

Mark, one thing to be careful with is using anti-seize since it has metal in it. You're introducing another metal into the system... and we all know what dissimilar metals can do around a boat! I must admit, though, I just learned that anti-seize has metal in it a few months ago, myself. I had always thought it contained tiny, tiny glass beads. :smt001

Instead, just use a good waterproof grease. In reality, the amount you used will be unlikely to cause any corrosion problems. But, better safe than sorry.

 

[rondds]

Dennis, any idea what that screw and ball thing does? Is it possible that the stuck ball blocked flow to one side of the engine leading to that one elbow heating up?

 

[MarkD]

Rialb, yes, my alarm is somewhat sporadic, but I did isolate it somewhat to a set of operating parameters like throttle changes and going above 3000 rpm etc. That, in combination with 1 hot exhaust elbow, makes me think its now a temp alarm going off. Just not a low speeds.

Brian, just undo the 2 hoses that come from your risers to the thermostat housing to see if your checkballs are hanging up.

Ron: Thanks for the parts explosion! That helps alot and the latter is exactly what I am speaking of. Pix are worth a thousand words. I didnt find even a little bit of debris in the thermostat housing/hoses or input passage to the elbow/riser. I think I should have, if there were impeller pieces throughout the system no? The thermostat itself has an opening waaaay smaller than the risers opening passageways and should be obstructed there first. At least thats my logical thought process working... LOL.

Dennis: Thats a good point on the unplugging of that sensor. If what I just did with the check ball doesnt fix the sporadic alarm, I will shut down the engine, unplug the first temp sensor, then restart. Give it a whirl and see if that cures the alarm. If not, I will shut down the boat again, plug it back in, and unplug the drive oil sensor wire (1 of them) and redo the entire test.


In the mean time, the thermostat and sleeve have been replaced completely with new components, so that should be 1 less thing on my mind. The check ball has been lubed up and should remain free for at least the next sea trail.... Can I completely eliminate this piece? What is the purpose? Does it prevent some sort of backflow of the exhaust system into the housing? or is it for temp control of the riser component? Remember, there is no such ball in the exhaust manifold fitting.... If someone could clarify that part, it might go a long way to helping me understand the cooling flow...

Thanks!

 

[MarkD]

Darn... I also did not type fast enough! Thanks for the antiseize clarification Dennis! I just didnt have any special lube 101, or anti corosion grease handy...

 

[Lazy Daze]

Dennis, any idea what that screw and ball thing does? Is it possible that the stuck ball blocked flow to one side of the engine leading to that one elbow heating up?

Yes, I think it's totally possible that's the problem.

What does this contraption do? I'm not 100% sure. At first (until seeing the picture), I thought it was going to be something that was temperature-activated and thus act as some type of secondary t-stat.

Bear with my ramblings here, I'm typing as I'm thinking...

Since everything is connected on one rod, it leads me to believe it's functioning more in regards to balancing pressure between the two sides (although, ultimately still controlling temp). If one mani was getting better flow from the "traditional" exhaust flow hose it would be "full" of water (I'm exaggerating for effect). Which means the other mani would have less water in it. If it had less water, it would have more air. Air is compressible. Which means the exhaust water going through this "T" would be able to push the ball that is on the side with air in it, which would open up that side to receive more water flow, thereby cooling down that mani.

My guess is that this "ball pushing" is constantly happening back-and-forth from one to side to the other, helping to balance out the exhaust water flow and keeping everything happy.

Again - I'm just theorizing here, I could be way off. Also, I hope what I wrote is at least coherent!:smt001

 

[MarkD]

Hmm... what would happen if I removed it totally? I honestly dont know what could happen, other than the engine taking a bit longer to warm up. Does that make sense?

I could also just order the new part and replace the entire thing (assuming thats the cause) and wait till it happens 2 years from now

Anyone else venture a guess as to what this part actually does for the engine?

 

[Lazy Daze]

I still don't know for sure, but I can tell you that this was a relatively recent (last few years, maybe?) design change for Merc. The older style simply had (4) hoses on the t-stat housing: Water inlet, stat housing to circ pump, and the (2) water exhaust hoses. How does this info help? :huh: :lol:

 

[MarkD]

Hi Dennis,

I was thinking about removing this completely. Thats why I was asking. Just a thought, could that part also be to prevent water backflowing into the system? I dont really see why it would need it there though...

Anyway, just thought I would ask. Will keep everyone posted as to what happens next.

Thanks again!
Mark

 

[Good Grief]

I have had the same problem on our boat w/ same engine. I tested the thermostat and temperature switch and found them to be right where they should be. Do you have a reservoir for your outdrive? If so I would check the level, mine has an alarm associated with it and when the boat was at the right angle it would sound the alarm. Topped off reservoir and fixed the problem. The outdrive reservoir alarm and high temperature alarm have different sounds.

 

[MarkD]

New Update: I finally was able to run the boat at the slip and although the check balls were freed up, the port elbow was getting hot again. I decided to remove the check balls and retest. The elbow immediately cooled down. Bad part no? Maybe not... read on... I went out for the day running over an hour at 3000-3400 rpm and heard NO additional alarms, until I came back to dock. The temp alarm went off when simply idling at the dock, and this time, the temp actually went up to 185-190 (on the gauge anyway). I kicked up the throttle from ~700 --> 1200 rpm in neutral and the temp started to drop, alarm silenced! Whats with this thing?

So I started thinking a bit more on the rationale for the temp uptick/alarm at the dock. Maybe, when i removed the check balls it opened up more flow that was obviously restricted prior. This part must prioritize water flow to engine components. Prior, these balls could have been keeping enough water flow inside the engine/housing to maintain adequate cooling, but when removed, took the excess water flow to the elbows. Hence the alarm at idle. Does that indicate a weak/worn impeller? That would be my guess.
Anyone else have an opinion?

 

[rondds]

Mark
there's always a surge in temp when coming off plane but it usually drops back down pretty quickly. I'm thinking impeller, esp after the little issue you had when winterizing last year. Thing is, why would an alarm trigger at 190? I thought the alarms would kick on more so around 200+. How hard is the impeller job?

 

[MarkD]

i am actually having a good friend who is also local to the boat and has done these things alot, take care of it for me during the week. I just dont have time otherwise I would do it myself. So you think that the impeller is the cultrit huh.... i think so too, and impellers are cheap to replace (even with the whole kit). will let you know what happens this weekend.

 

[Lazy Daze]

Mark, definitely keep us posted - it's always good to hear about the final verdict.

I FINALLY had a chance to ask one of our technicians about the spring thing in T-stat. It is not to "balance" the flow as I had originally pondered. It is meant to increase water flow to the block at idle (and close to idle) speeds. Once the revs pick up a bit, the spring contraption will allow the water to go right out to the exhaust.

A bad spring could cause an overheat condition at low speeds - not higher speeds as you are experiencing.

I guess I had originally assumed you had already checked the impeller. I think you're on the right track with getting that done.

Good luck!

 

[MarkD]

Thanks for checking on that spring thing Dennis. I will let you guys know what happens during or after the weekend (assuming my buddy gets the job completed). Have a great 4th if we dont talk!

 

[MarkD]

FWIW, my buddy was able to do the impeller. He said it cost something like $30 for the part plus some lubricant and an hour or two work. Hoping this solves the issue, although he said the impeller didnt look too bad when he removed it. More to come.

Thanks all!

 

[Firerooster]

Did he back flush the entire system? Sand, debris and impeller parts stuck in the cooling system obviously cause temp increase

 

[Lazy Daze]

Mark, I'm not second guessing your mechanic, but did the wear plate look OK? If that plate gets grooves in it, it will decrease the effectiveness of good impeller. Just a thought.

 

[MarkD]

Hi Dennis and all....
Sorry for the lack of follow up. I have been swamped at work. You can second guess all you want Dennis, no sacred cows here!! The guy who replaced the impeller told me everything looked pristine. He also left me the old one. The old impeller looked brand new. In fact, it still had the original rubber casting marks (where the mold meets in the middle). He also said the wear plate was perfect. Zero grooves. I also put back the check balls to original state, except reversed (left to right) to see if the hot riser followed that side of the check ball.... I took it out again to test LAST weekend. It ran great for a 30 mile run. No alarms, no overheats. Behaved nicely. I thought it was a done deal and fixed. THIS weekend I took it out again for a similar run. In the middle of the run, the alarm chirped once again. I checked the temp and of course it was a shade over 170 (which is normal). Over the course of an hour, it made 2 additional chirps. Can you say frustrating!! FWIW, the hot to the touch riser did follow that check ball that I turned (L-->R). I am not sure that has anything to do with this at all but I want to include all facts.

At this point I am open to suggestions.

-Mark

 

[rondds]

clip the wire to the alarm! LOL

 

[Lazy Daze]

Mark, I didn't read back through your whole post so forgive me if this has been answered...

Did you try running with the drive fluid bottle alarm wire disconnected? You only need to disconnect one of the wires (put some electrical tape over both open ends. Run it for a few days like that and see if you still get the alarm.

I don't know enough about the other two things that can set off the alarm (high water temp and low oil psi) to say whether or not you can simply disconnect them (to experiment) as well.