Impeller replace or not after overheating

[Swooper]

If I’m remembering correctly, every time the strainer is cleaned, there will be a couple feet of suction hose with air prior to the impeller. This is my first inboard (A22 with M5). Are they all like this? I’m a pipe/water/design guy at work - why no check valve? I suppose corrosion  blockage issues?

[oldjeep]

51 minutes ago, Swooper said:

If I’m remembering correctly, every time the strainer is cleaned, there will be a couple feet of suction hose with air prior to the impeller. This is my first inboard (A22 with M5). Are they all like this? I’m a pipe/water/design guy at work - why no check valve? I suppose corrosion  blockage issues?

Even without the strainer, the intake hose is always empty after the boat comes out of the water - gravity still being a thing and all.

[23LSVOwner]

14 hours ago, Swooper said:

If I’m remembering correctly, every time the strainer is cleaned, there will be a couple feet of suction hose with air prior to the impeller. This is my first inboard (A22 with M5). Are they all like this? I’m a pipe/water/design guy at work - why no check valve? I suppose corrosion  blockage issues?

Freezing issues.

[23LSVOwner]

If you give the throttle a quick blip in neutral when you drop the boat in the water it will prime up almost instantly.

[AxleGrease99]

14 hours ago, oldjeep said:

Even without the strainer, the intake hose is always empty after the boat comes out of the water - gravity still being a thing and all.

It’s pretty incredible how much water runs out of that motor when the boat is pulled out. I’d say it drains from the surf pipe for a good 10 minutes. Does anyone know what the system holds? 2 gallons would be my estimate. 

[matthewmiller01]

Does anyone have a pic of the impeller cover?  I just had my first one eat itself (I'm assuming the impeller ate itself- I'm opening it up tomorrow when I have a spare).  It was just after I idled away from my dock.  Probably a 4 minute idle period.  I will be taking the advice of neutral/reverse from now on.  Can anyone help this newbie on how to get to neutral?  I came from Mercruiser DTS - those had a neutral button.

2020 25LSV

63ish hours on my M6Di

Thanks in advance.

[formulaben]

12 hours ago, AxleGrease99 said:

It’s pretty incredible how much water runs out of that motor when the boat is pulled out. I’d say it drains from the surf pipe for a good 10 minutes. Does anyone know what the system holds? 2 gallons would be my estimate. 

Can't speak with any authority with the newer engines, but when I winterize my boat with anti-freeze, it takes almost a full 5 gallons (in circulation); if I only put 4 in the bucket then the pump at the bottom of the bucket will start sucking air.  Once I stop, I get about half of it back, so I'd say it's easily 2+ gallons for older Monsoons.

 

[ahopkins22LSV]

15 hours ago, matthewmiller01 said:

Does anyone have a pic of the impeller cover?  I just had my first one eat itself (I'm assuming the impeller ate itself- I'm opening it up tomorrow when I have a spare).  It was just after I idled away from my dock.  Probably a 4 minute idle period.  I will be taking the advice of neutral/reverse from now on.  Can anyone help this newbie on how to get to neutral?  I came from Mercruiser DTS - those had a neutral button.

2020 25LSV

63ish hours on my M6Di

Thanks in advance.

Your throttle has a neutral button. Just in front of the throttle lever. Push and hold it and move the throttle into forward. A blue indicator light to the rear of the throttle level will turn on when it is engaged properly. 
 

Here is a picture of the M5 impeller placement. Same on the M6, just black not grey paint. 

[matthewmiller01]

On 7/15/2020 at 12:10 PM, ahopkinsVTX said:

Your throttle has a neutral button. Just in front of the throttle lever. Push and hold it and move the throttle into forward. A blue indicator light to the rear of the throttle level will turn on when it is engaged properly. 
 

Here is a picture of the M5 impeller placement. Same on the M6, just black not grey paint. 

Thank you, ahopkinsVTX!

I found the neutral.  It is exactly as you described.

I also found the impeller... after I found the engine coolant thermostat.  I'm such a rookie.  I also found where all of the pieces of impeller end up - the inlet to the engine heat exchanger is just under the ribbed, square thing in your pic.  Move the square thing (whatever that is), unbolt the top of the heat exchanger, and all of the pieces are right there.  The heat exchanger tubes are tiny (maybe 1/8" in diameter or so), so all of the pieces collect nicely right there for easy cleanup.  What took me 2 1/2 hours yesterday evening should take me only about 15 minutes the next time (assuming the engine is cool).

[Bird]

I have had overheating twice at start up. So as we launch before backing off trailer I start engine in neutral and give a few revs before backing off. Last thing I want to do is start our day changing out impeller.

[MVC]

My M5 ate it’s impeller At 7 hours! Thanks for the engine rev tip. Bakes online site said some of the early Sherwood impellers were defective. Would be nice if Malibu did a recall. I guess they figure that the owners can do the work on their own dime when the engine over heats and goes into ‘limp home mode’, exactly as it happened to me.  

[UWSkier]

On 7/15/2020 at 9:10 AM, ahopkinsVTX said:

Your throttle has a neutral button. Just in front of the throttle lever. Push and hold it and move the throttle into forward. A blue indicator light to the rear of the throttle level will turn on when it is engaged properly. 
 

Here is a picture of the M5 impeller placement. Same on the M6, just black not grey paint. 

I remember the idea of the FEAD was to make things easier to work on but judging from that pic... Think a Johnson impeller might be an easier swap. 

[ahopkins22LSV]

37 minutes ago, UWSkier said:

I remember the idea of the FEAD was to make things easier to work on but judging from that pic... Think a Johnson impeller might be an easier swap. 

I’ll let you know by next weekend, I’m due to change mine. 

[csleaver]

3 hours ago, MVC said:

My M5 ate it’s impeller At 7 hours! Thanks for the engine rev tip. Bakes online site said some of the early Sherwood impellers were defective. Would be nice if Malibu did a recall. I guess they figure that the owners can do the work on their own dime when the engine over heats and goes into ‘limp home mode’, exactly as it happened to me.  

Malibu has issued a service bulletin that recommends replacement of the earlier impeller in boats built prior to September 2019 and Malibu dealers should be aware of it.

Recalls are only done through the USCG, by dealers, for potentially dangerous defects that can result in things like fire or explosion or uncontrolled acceleration or loss of steering.

A good example is the recall last year for leaking fuel pump grommets that affected almost every boat builder that used in tank fuel pumps.  Or, the one for possible short circuit of the engine breaker on PCM/Challenger 6.0L from a couple years ago.  Or, acceleration issues on Nautiques about 3 years ago.

USCG recalls are tracked, letters are sent to registered owners and are not closed until a repair claim is filed.