Just overheated the engine

[scgunner]

Wow, that sounds like a lot of impeller vanes floating around in your cooling system, no wonder it was overheating. I've had problems after losing one vane. That's the thing, if you pull an impeller missing a vane, the vane itself doesn't flush out of the system, you'll have to track it down and remove it.

[britinusa]

Just a thought, when I rebuilt the engine exhaust system I had to repair the fiberglass muffler where the engine exhaust connects to it. So I also added the silicone hose with a bump in it to reduce the vibration at the connection.

[Ron Hill]

Paul : Like I've mentioned before, besides changing to a hump hose change out the old stiff wire reinforced hose from the anti syphon valve to the nipple on the exhaust riser.  Make sure that hose is a nimble nylon reinforced hose!!

A thought

[mregan]

Might have spoken too soon.  Went out for a sail Sunday. Motored about 20 min. Temp steady at 160. On thr return trip, also 20 min motor.  Was running at 160 then creeped up to 180.  When got close to the marina throttled down and temp dropped to 160.
I did notice thr was a bit of water in the bilge so something is still leaking. Will have to explore more next weekend.

[glennd3]

The main thing is that your engine seems fine, not effected from the initial overheating.

[KWKloeber]

I did notice thr was a bit of water in the bilge so something is still leaking. Will have to explore more next weekend.

It's seawater and not coolant in the bilge?
Check the Hx hose clamps and that the cap ends are tight, rubber gaskets not leaking.
Stuffing box checked lately?

[mregan]

It's clear water. A little dirty but clean. No anti freeze in it.  When I noticed the hose to the muffler was leaking and I loosened the clamp. I was able to raise up the hose and The exhaust pipe it was attached to would hinge up an inch or so. Didn't think anything of it but looking at Stu's exhaust replacement article I'm wondering if that exhaust section is supposed to be rigid with no movement.

[Stu Jackson]

......but looking at Stu's exhaust replacement article I'm wondering if that exhaust section is supposed to be rigid with no movement.

The exhaust RISER should be rigid, because it is supposed to be firmly screwed into the flange at the manifold end.

[Noah]

You should be able to run engine, in gear at the dock, with all compartments/doors open and aft bunk removed, and spot any water leaks from raw water systems. Just make sure you are very careful to not get caught up in any spinning parts or burned. May be a bit scarry but doable.

[Ron Hill]

mre : Which hose to the muffler?? ("I noticed the hose to the muffler was leaking")

The inlet hose into the muffler from the stainless riser "should be a "blue hump hose" and flex; while the black exhaust hose is ridged.

A few thoughts

[mregan]

Inlet hose into the muffler. It's a black rigid hose. Definitely not the blue hump hose.

Like I had mentioned, I had unscrewed the clamp on the inlet hose where it attached to the muffler. I was trying to get it off the muffler stub to see if the overheating had cracked or deformed the fiberglass stub. It was sitting about an inch up on the stub. As I lifted the hose up to try to get it off the stub, the riser moved up about an inch which I wasn't sure it should be doing.

I'm going to do what Noah said and look over everything. Do I have to be in gear or can I leave the boat in neutral.

[Noah]

Not absolutely necessary to be in gear, but it will heat the engine faster and you can see if stuffing box is dripping appropriately to cool shaft when it is turning.

[Ron Hill]

mre : The whole idea of the flexible blue Hump hose is so that all of the engine vibrations are NOT transmitted to that inlet hose going into the muffler and crack that inlet seal. 
That is what is happening with your black stiff hose from the riser into that inlet of the muffler!!
 
Of course, if you move that stiff hose on the muffler it will lift the riser slightly because it is connected (bolted) to the engine and the engine mounts will give!

The same idea of the nimble nylon hose from the anti syphon valve to the nipple going into the riser. If there is a stiff wire reinforced hose from the factory, the engine vibs will stress that nipples weld cracking it and it will break and leak!!

Get a hump hose and change that raw water hose from the anti syphon valve. 

A few thoughts

[Roland Gendreau]

MRE

If the riser moved up an inch, that is more than I would expect the whole engine to move on the mounts.  Look over the condition of your riser carefully; mine failed 2 years ago , and it broke right where the water injection connection is made.   

Roland