Missing raw water impeller vanes

[Mad Manc]

Of course my raw water impeller failed on my first trip out with friends this year. Hino WO4CT (150HP). When I opened the pump there were only 4 1/2 of the 8 vanes left in the pump! Picture below.

I have back flushed all the hoses all the way to the manicooler and transmission cooler. I’ve looked in the manicooler inlet with a borescope and can’t see any debris.

My only conclusion is that the missing pieces got ground up enough to get into the manicooler tubes.

Any thoughts/suggestions?

Next step is to try to “snake” the manicooler tubes as best I can
.

[bobofthenorth]

Pretty common. As you have already indicated, you need to go looking for the missing bits because its highly unlikely they made it through to the water exhaust.

[smitty477]

When impeller pieces flow to the Hino manicooler it looks something like this...

[Mad Manc]

That’s what I’d have expected but mine appears pretty clean - from my borescope view. Pulling the end caps today hopefully

[smitty477]

Have you looked in the aftercooler?
When flushing use a much volume as possible and 'pulse' it on and off for periods of time.
Have you tried a good vacuum while flushing from the other end?

[Mad Manc]

My raw water goes from the strainer, through the tranny cooler then to the raw water pump and from there to the manicooler (not like the manual shows it). I have tried pulsing, sucking etc…

[MacPhid]

Can you not just pull the inlet hose off of the tranny cooler to check for impeller piecees? Do the same for intercooler and manicooler. Not hard to pop the hose off.

James

[Mad Manc]

Pulled off every hose in the system all the way to the manicooler!

[Pcpete]

Those little chunks can be a pain to get out and it will take patience. I have a chunk of speedometer cable for just this job. It’s flexible but it doesn’t compress and has just enough abrasive quantities to clean up buildup in the tubes. Smitty477’s pictures in post number three are right on and there’s the concern of upsetting the isolation of the bundle, especially with both end caps off. I made a dummy, open end cap out of ipe, aka ironwood, that bolts up and compresses the oring but is wide open in the center to provide access to the tubes.
Plywood would work just fine. I will admit to a small cheat in making it, I have a spare complete manicooler gathering dust at home to work with. May it gather dust for many years.
Good luck.

[Mad Manc]

Pete, any chance you have the dimensions for the dummy end cap?

[smitty477]

If you look at post #3 above in the top right picture of the cap you can see the back of the round pipe plug mounted in the middle of the intake caps on the newer Hino manicoolers.
With those you can carefully remove the round pipe plug in the middle without disturbing any of the 4 bolts holding the cap and do some inspection and cleaning in there.
With all that said there is never a better way to really thoroughly clean a manicooler except for taking it off.

[Mad Manc]

Think I have the older style so I’m pulling the end covers off and cleaning that way.

[fishexit]

A piece of brass rod from the hardware store that just fits
and is longer worked for me when tube was out. Speedometer cable would work better especially if in place

[2850Bounty]

All good advice!
suggestion:
After you have retrieved all of the fragments and are ready to install your new impeller, coat it with glycerin from a pharmacy.
DO NOT use any petroleum products!

Make sure that the impeller veins are folded in the correct direction of rotation!

[Mad Manc]

I bought the “kit” with Jabsco impeller lube. Hopefully, that’s OK. I have other spares and will keep glycerin in mind if I use them.

[Mad Manc]

Well I’ve opened up, vacuumed and back flushed every hose from the seawater strainers to the manicooler, opened the mani cooler and “snaked”, back flushed and forward flushed every cooling tube and no signs of the missing impeller pieces! At this point I’m going to reassemble everything and start her up - monitoring temps very closely. Wish me luck!

[Pcpete]

Only the best of luck!

[2850Bounty]

Before you get too far ahead of yourself, find the source of the original issue that caused the impeller to come apart.

[Mad Manc]

Well, apparently I got lucky. Went out today, ran for about an hour including about 5 minutes at WOT. Temps stable and in limits on both engines. Only surprising thing was that I hit an indicated 18 knots at WOT which is the fastest I’ve ever seen in this boat!

[Pcpete]

Great!