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M15 engine is overheating

Jun 20, 2021
17
Catalina 30 Arkansas River
Where would you hook up your hose pipe to do the flush in each direction?
I would unhook the water hose from the outlet side (starboard) of the water pump. And unhook the recirculation line from the seacock. Use a brass cone shaped spray nozzle on a water hose. It should fit snugly into the coolant hoses. Flush the engine thoroughly in both directions.
 
Oct 22, 2014
15,806
CAL 35 Cruiser moored EVERETT WA
Also how exactly do you remove the thermostat from the housing while the engine is running?
You do not.
I would turn off the engine (cold engine). Remove the housing cover. Thermostat sits down beneath cover. Some are sitting there, held in place by the cover, others are screwed into the engine block.

Heat a pan of water on the stove. Check with a thermometer. When it reaches 135F drop the thermostat into the water. The valve should open. If not continue heating water to 150F. Valve should be fully open at 150F. If not the thermostat is the wrong one for your engine or it has failed.

Replace with one correct for your engine. Reinstall thermostat and then install the cover.

I would connect a water hose to a small bit of hose. Put it onto the engine using one of the hose nipples in the water coolant line. Use a hose clamp. Turn on the water. I should flush out in the normal way of water out of the boats engine.

Check the attached manual (in my earlier post) for connection points.
 
Sep 15, 2021
15
Catalina 30 30 san diego
Hey thanks this is all great info and will try it tomorrow and I’ll provide feedback.

I did look at the manual that you attached earlier but I do not see anything about the coolant system. Can you please provide a page reference at the pics where to connect up to do the flush?
 
Oct 22, 2014
15,806
CAL 35 Cruiser moored EVERETT WA
Can you please provide a page reference
Post #5 by @sail sfbay on page 31/32 you get a diagram of the cooling system.
I would access the system at one of the points with a hose nipple that will allow me to push water through the system.

Just like I would attach a hose to my truck engine to flush the coolant system.

You’ll want to flush the water into a bucket or overboard.

I understand that the boat is new to you, but is all this DIY mechanical stuff also foreign. Some of what we say assumes you have a basic knowledge. If not let me know.

One of the best learning tools around is a basic engine class from a local community college. They provide insight into mechanical stuff that many of us here got in high school shop class.
 
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Jan 19, 2010
938
Catalina 34 Casco Bay
Don't assume that the new pump has a good impeller.. Remove the pump cover and have a helper engage the starter WITH the stop pulled. If the shaft turns and the impeller stays in place, then you've joined the victim of China made impellers Club..
However, if the impeller turns and water is exiting the transom then you probably have an air embolism in the fresh side. Odds then are with the hot water heater..
 
Sep 15, 2021
15
Catalina 30 30 san diego
The pump was brand new I got from the manufacturer so it isn’t Chinese made impeller. I’ll pull the cover though and see, I did get water coming out of the pump with the engine running though so I know it was doing something right.
 
Sep 15, 2021
15
Catalina 30 30 san diego
I do
Post #5 by @sail sfbay on page 31/32 you get a diagram of the cooling system.
I would access the system at one of the points with a hose nipple that will allow me to push water through the system.

Just like I would attach a hose to my truck engine to flush the coolant system.

You’ll want to flush the water into a bucket or overboard.

I understand that the boat is new to you, but is all this DIY mechanical stuff also foreign. Some of what we say assumes you have a basic knowledge. If not let me know.

One of the best learning tools around is a basic engine class from a local community college. They provide insight into mechanical stuff that many of us here got in high school shop class.
have some mechanical knowledge and understand the terms being used. I just know one little thing can lead to catastrophic consequences so I like to ask a lot questions is all.
 
Oct 22, 2014
15,806
CAL 35 Cruiser moored EVERETT WA
I like to ask a lot questions is all.
That is a great way of thinking.

Most of the things that can happen are forgiving of mistakes. You don’t want to repeat them frequently, but I have found I can get away with a few oops.
 
Feb 26, 2004
21,898
Catalina 34 224 Maple Bay, BC, Canada
Stu, as I mentioned I did take the line off that is down stream from the pump and water we flowing out the line when the engine cranked.

I didn’t think the pump needed to be primed, can you provide any detail on doing this?
Yeah, just suck on the inlet hose to the pump with the seacock open. When water gets to your lips, disconnect the hose from lips and reconnect to pump.:)
 
Jan 19, 2010
938
Catalina 34 Casco Bay
The pump was brand new I got from the manufacturer so it isn’t Chinese made impeller. I’ll pull the cover though and see, I did get water coming out of the pump with the engine running though so I know it was doing something right.
Don't be too sure where the impeller is made. Just because the pump is made in MI doesn't mean that the impeller is. similar to GM engine computer chips....
 

Ward H

.
Nov 7, 2011
3,092
Catalina 30 Mk II Barnegat, NJ
Stu, as I mentioned I did take the line off that is down stream from the pump and water we flowing out the line when the engine cranked.

I didn’t think the pump needed to be primed, can you provide any detail on doing this?

-Jon
The pump shouldn't need to be primed but it may if there is a slight air leak at the cover plate o ring.
This last spring I was having intermittent issues with no water flow when starting after a day sail. Tried lots of things.
Then I went back to Stu's idea that the pump was losing prime.
All my issues went away when I replaced the o ring and lubed it with dish soap when installing. No more issues.
 
Jul 5, 2011
598
Oday 28 Madison, CT
If the thermostat is stuck closed, this won't help. But it's a good place to start.

I'd remove the impeller cover off the old pump and see if it's missing any vanes.
Yes and if missing track where they went as they won't just dissolve. With me they would up at the end of the hose at the HE connection. Clean out the hose, pull HE end cap and clean that area as needed.