Tracking down impeller parts

[Cullie140]

I have a shredded impeller. I definitely haven't found all pieces but not sure where i should look. So far i have the hose from the raw water pump to power steering cooler off and its clear, found some pieces. That hose on PS cooler was pain in the ass to get off so not sure what best spot to look next is. The hose exiting the PS cooler has some kind of connector on it ( pic attached) Wondering if its inline strainer? If so how does it come apart? Access to engine is horrible so teying to avoid taking every hose off one by one. 2004 SR sundeck 240 6.2 mpi B3.

 

[mrsrobinson]

I am not an expert in your engine/boat. I chased down an overheating last year that turned out to be impeller bits. If I was you I'd start at the point where raw water exists/leaves the raw water pump, working my way down, hose by hose, remove/inspect/reinstall. In my case it was the first place where the raw water moves thru something smaller, tubes, the HEX:

I wish I had started there first, I started with the transmission cooler instead, which is further down the line. Lessons learned, now I know.

I don't think my prior raw water cooled gas engine boats had inline water filters. I never saw/found one.

This "appears" to be the 6.2 raw water flow diagram. Note this diagram shows "Heat Exchanger (Closed Cooled Models Only)", not sure if yours has a HEX:

Water Flow Diagrams - Mercury MX 6.2 MPI Installation Manual [Page 74]

Mercury MX 6.2 MPI Manual Online: Water Flow Diagrams. NOTE: Certain components in the following diagram may look different than on your particu- lar power package, but the water flow paths remain similar on all engines. Closed Cooled Models c d e Page 74 of 77 a k b f g a - Exhaust...

www.manualslib.com

 

[Cullie140]

I dont have a heat exchanger but that diagram helps. That inline device appears to be a check valve before the cool fuel box. Wondering if impeller bits could be stuck in check valve. The hoses appear to be crimped onto the check valve, not sure i can get them off.

 

[mrsrobinson]

You didn't ask but; your boat is a 2004, if you do not have a history when the hoses were replaced I recommend you replace them as you are removing them.

https://www.thehulltruth.com/boating-forum/1100897-mercruiser-6-2-mpi-bravo-3-overheating.html

"The spring your talking about is in the check valve which is upstream of the water distribution manifold. This can catch pieces of impeller and other debris like sea grass however this check valve was removed from the system on engines equipped with the cool fuel 3 system. The valve stopped hot water from running backwards in the system at shutdown and heating up the Cool fuel 2 and causing vapor lock. With this boat being a 2006 it should have the Cool fuel 3 system. I see that you mention freshwater, is this boat still in freshwater ? If not how long has it been in salt ? One more thing, what is the water pressure with the key on engine not running ? 34 PSI is extremely high and that sensor from amazon may be bad. With a properly working sensor you may show .5 or 1 psi key on engine off but if it shows more like 5 or 10 the sensor is bad"

 

[Scott215]

That valve is what I believe to be a check valve. I have seen other posts about that

 

[scoflaw]

Start simple, backflush.

 

[Cullie140]

Start simple, backflush.

 

[mrsrobinson]

so not sure what best spot to look next is.

Curious if you have taken the boat out for a test cruise since doing this? I took mine out for a test cruise after each thing I did, before moving on to the next one.

 

[Cullie140]

If i backflush from the T housing will it flow back through the check valve upstream from cool fuel box?

 

[Lazy Daze]

Did you take the lower engine cowl (the fiberglass "surround") that screws to the deck? That helps quite a bit for access and is easy to do.

Check t-stat housing.

 

[Cullie140]

Did you take the lower engine cowl (the fiberglass "surround") that screws to the deck? That helps quite a bit for access and is easy to do.

Check t-stat housing.

Had all the hoses off thermostat housing i didnt see any debris there. Taking the cowl off did help with front access around water pump but still horrible access to sides of engine especially down by block. Im a bigger guy. So I’m confident intake up to power steering cooler on the back is clear, what I’m not sure of is power steering cooler discharge all the way to thermostat. Lol I know that’s a lot of area. I figure it was probably tough for pieces to make it pass that check valve. Just not sure how to inspect that check valve or if I need to inspect the fuel cooler I’m not familiar with that set up.

I did run engine on Muffs today and seem to have very good water discharge after replacing the impeller and backer plate with the rebuild kit so concerned that maybe loose pieces may clog up something down the road but at the moment appears to be getting good flow throughout engine

 

[Lazy Daze]

"still horrible access to sides of engine especially down by block"

Yup - welcome to boat mechanics 101. Many boats are even worse.

You really need to look INSIDE the t-stat housing (take it off).

Pull the one way valve off and inspect.

What type of fuel cooler do you have? if you have CF3 it's before the pump. If you have the older version, it's behind the stbd motor mount and is just a straight tube - but you should be able to get at least the downstream hose off to inspect.

 

[mrsrobinson]

Had all the hoses off thermostat housing i didnt see any debris there. Taking the cowl off did help with front access around water pump but still horrible access to sides of engine especially down by block. Im a bigger guy. So I’m confident intake up to power steering cooler on the back is clear, what I’m not sure of is power steering cooler discharge all the way to thermostat. Lol I know that’s a lot of area. I figure it was probably tough for pieces to make it pass that check valve. Just not sure how to inspect that check valve or if I need to inspect the fuel cooler I’m not familiar with that set up.

I did run engine on Muffs today and seem to have very good water discharge after replacing the impeller and backer plate with the rebuild kit so concerned that maybe loose pieces may clog up something down the road but at the moment appears to be getting good flow throughout engine

I can't speak for your boat/engine, for my boat before and after removing the impeller bits did not change the water flow at the dock. After though, at cruise speed, it definitely brought the temperatures back to normal.

That's why I suggested a cruise. Each time I took the next step and cleaned out something, the boat ran great at the dock and at temperature. That was not the case though when I took it out for a cruise. The engines would quickly heat up again. I got good advice here on that, clean something, take it out for a test cruise, see if they're still running hot. Running at the dock, in your case on the muffs, is different than running at cruise speed.

I personally don't think you can do any more damage with any remaining bits you didn't get out, especially if you're working in order from the raw water pump to the exhaust. Find bits, remove bits, take boat for test cruise If it's still running hot, go further down the flow looking for more bits, lather, rinse, repeat. I'm not the expert though, I'm sharing the advice I got on here when I was working through this, others may disagree with that.

 

[Cullie140]

"still horrible access to sides of engine especially down by block"

Yup - welcome to boat mechanics 101. Many boats are even worse.

You really need to look INSIDE the t-stat housing (take it off).

Pull the one way valve off and inspect.

What type of fuel cooler do you have? if you have CF3 it's before the pump. If you have the older version, it's behind the stbd motor mount and is just a straight tube - but you should be able to get at least the downstream hose off to inspect.

I hear ya on no sympathy for engine access lol. Its my 2nd boat and first was way easier so guess im spoiled.

Will take off t stat housing and look. Not sure what model of fuel cooler but it is on port side before water distribution housing and water circulating pump. Looks more like a box than straight tube.

The check valve has ear crimp hose clamps, just googled to figure that out. So i at least know how to remove those now. Should be ok to put standard hose clamps back on?

 

[Skip ThunderBolt]

I had to replace both my impellers this year. Stupid Ohio River/ Harrods Creek. I pulled all the hoses and found most of the impeller pieces in the impeller housing, thermostat, and hose leading to the thermostat. You should be fine once you get most of the big pieces out and confirm you are NOT overheating.

 

[Cullie140]

I can't speak for your boat/engine, for my boat before and after removing the impeller bits did not change the water flow at the dock. After though, at cruise speed, it definitely brought the temperatures back to normal.

That's why I suggested a cruise. Each time I took the next step and cleaned out something, the boat ran great at the dock and at temperature. That was not the case though when I took it out for a cruise. The engines would quickly heat up again. I got good advice here on that, clean something, take it out for a test cruise, see if they're still running hot. Running at the dock, in your case on the muffs, is different than running at cruise speed.

I personally don't think you can do any more damage with any remaining bits you didn't get out, especially if you're working in order from the raw water pump to the exhaust. Find bits, remove bits, take boat for test cruise If it's still running hot, go further down the flow looking for more bits, lather, rinse, repeat. I'm not the expert though, I'm sharing the advice I got on here when I was working through this, others may disagree with that.

Great advice, i just cant put back in lake this season. My ramp is already closed. Doing my best to clean out now and have a smooth spring launch but that may not happen now

 

[Lazy Daze]

I hear ya on no sympathy for engine access lol. Its my 2nd boat and first was way easier so guess im spoiled.

Will take off t stat housing and look. Not sure what model of fuel cooler but it is on port side before water distribution housing and water circulating pump. Looks more like a box than straight tube.

The check valve has ear crimp hose clamps, just googled to figure that out. So i at least know how to remove those now. Should be ok to put standard hose clamps back on?

With that location of the fuel cooler, then you have a spin-on fuel/water separator? "Box"... yes, on the outside it's a black, plastic box. The "cooler", itself, is a tube. The fuel pump is also inside the box. Look up "cool fuel 2".

Yup, just twist/cut those ear crimp (sometimes referred to as Oetiker clamps after the guy that invented them). You could get the crimp tool and new clamps if you want - but, yes, standard worm gear clamps are totally fine.