Temp range?

BillyK

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Jan 24, 2010
502
Catalina 310 Ocean City, NJ
Last year, our first for the 310, my engine temp was rock solid at 170 until we hit high temps in the summer and would go as high as 180. This year so far it is sticking a bit under 180. I've checked the strainer and it is clean. Fresh water boat whole life, 670 hours, water pump up graded and all coolant lines changed out and fresh coolant. Should I care?
Temperature range for the M25-XPB engines is 170-190 so you're ok if that's what you have.. the change in behavior is something to look into.. have you changed the thermostat to be sure its not that?
 
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JRT

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Feb 14, 2017
2,037
Catalina 310 211 Lake Guntersville, AL
Thanks all, @BillyK. I haven't been able to check, just like to keep an eye on it every time and watch for changes. I'd say right now after 3 trips out she is running solid at just a hair under 180 on the runs home for usually 45-60 mins at 5-6 knots and as I recall 2700 ish rpms.
 
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Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Thanks all, @BillyK. I haven't been able to check, just like to keep an eye on it every time and watch for changes. I'd say right now after 3 trips out she is running solid at just a hair under 180 on the runs home for usually 45-60 mins at 5-6 knots and as I recall 2700 ish rpms.
It looks like you are in good shape. Checking the condition of the heat exchanger is always a good idea, although I suspect a fresh water boat would have less possibility of blockage. My boat is saltwater born and bred, so I pulled my heat exchanger off and had it flushed and pressure checked at a radiator shop when the engine hit around 1,000 hours, even though it was working fine.
 
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Dec 16, 2011
257
Catalina 310 Atlantic Highlands
I'm no expert, but when was the last time that impeller was changed? It doesn't look so good.
 
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BillyK

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Jan 24, 2010
502
Catalina 310 Ocean City, NJ
WOW.. look at that impeller! SawyerCurt is right.. i would replace it, there's a good chance that's your issue.
 
May 12, 2004
1,502
Hunter Cherubini 30 New Port Richey
Agreed. Replace ASAP. If that were to deteriorate any further and break up, it could possibly block chambers in your heat exchanger causing you a lot more headaches.
BTW, how is that impeller even sucking water?
 
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DaveJ

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Apr 2, 2013
449
Catalina 310 Niagara-on-the-Lake
I agree to change it, right away. But I have seen worse that work fine. But it looks like it's about to self destruct. I think it would still pump OK, for now....

Cheers
dj
 

JRT

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Feb 14, 2017
2,037
Catalina 310 211 Lake Guntersville, AL
Ok thanks all, I have a replacement, I guess I don't understand what is bad in the picture. Any tips I should take away?
 

JRT

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Feb 14, 2017
2,037
Catalina 310 211 Lake Guntersville, AL
Easy fix yesterday for a change! No sailing but my daughter had fun with the canoe around the marina. Hope for some wind today to make high lake bearable.

20200524_120936.jpg80s on the
 
Feb 8, 2014
1,300
Columbia 36 Muskegon
Got a 140 degree thermostat in mine and if running hard it stays exactly at 140, if running at lesser speeds it runs right under 140. I've got one of those temperature indicator strips on the heat exchanger and it reads 140, might want to use something similar to get an idea of max temp being reached.
If it's raw water cooled, 140 is the correct temp as salt will precipitate and block things up above that. But if it's an M25, it should be fresh water cooled and needs a 180 deg t-stat. The little M15 / 5411 that's in some old C30's is raw water cooled and has a 140 t-stat.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
I think this will lead to 180 degree water out of the tap? The best thing I did on the boat was to put a tempering valve right at the head sink, I believe it is good at 38 C ??? Not only can you still put your hands in at that temperature, I find there is more hot water come Sunday morning.
 
Feb 14, 2014
7,399
Hunter 430 Waveland, MS
Any tips I should take away?
Yes.
The grey circular area is the worn seal against your pump's face plate.
The new one is a perfect circle.

That face plate seal will continuously bypass and reduce your water flow.

The flex vanes are about to break off and lodge in your exchanger.

Changed, just in the nick of time!!
Jim...
 
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Jan 7, 2011
4,726
Oday 322 East Chicago, IN
Ok thanks all, I have a replacement, I guess I don't understand what is bad in the picture. Any tips I should take away?
I am not so sure the impeller would even turn...it looks like it is completely delaminates from the hub that makes it turn.

I see you already changed it, can’t wait to hear how well it works now.

Greg
 

DaveJ

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Apr 2, 2013
449
Catalina 310 Niagara-on-the-Lake
The flex vanes are about to break off and lodge in your exchanger.

JamesG, much better response than mine, explained simply. Only so much I can do on a phone....

JTR, glad you posted this, some of us need the reminder to change that impeller....even if the temperature reading is OK. Mine has been in 2 years, will order the new impeller tomorrow.

Cheers
dj
 

JRT

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Feb 14, 2017
2,037
Catalina 310 211 Lake Guntersville, AL
Got out yesterday, water temp was 79-82 degrees, run of 2500 rpm for 45 min temp gauge showed a few degrees under 180. Ran her a bit harder coming back and stayed below 180 by maybe 1-2 degrees. I'm disappointed that the new impeller did not get me back to 170. We have a lot of grass in the lake but the stainer is clean and flow is good and increases with more throttle.
 
Feb 14, 2014
7,399
Hunter 430 Waveland, MS
I'm disappointed that the new impeller did not get me back to 170
Sounds like you finally cleaned your temperature sensor too.
Crud on that sensor insulates it a bit or lower sensed temps.

Most diesel engines temperatures are controlled by its Crude Thermostat.

180°F sounds great.
Jim...