Bravo III impeller fins missing- what to do next?

[Kwilson0824]

Hi everyone, I recently purchased a newer used boat and changed the fresh water pump impeller since the seller said it had never been changed. The boat is a 2004 I/O with a Mercruiser 350 Mag MPI and Bravo III drive, fresh water cooled. The boat is 10 years old and only has 34 original hours. Basically sat inside his airplane hanger on a trailer most of its life.

Anyway, before I changed the impeller I took the boat out for a couple hours on a local lake and everything ran great and temperature gauge was showing around 170 degrees.

I just pulled the old impeller off and out of the housing and found that 3 fins were broken/missing. I found one of the broken fins lodged in the impeller housing itself. The guy at the local boat parts store told me I need to try to find the other missing two fins, but I am having trouble finding them.

My question is, how important is it for me to find the other two fins? Will the engine be ok if I'm not able to find them ?

What areas should I focus on looking?

Currently, the boat runs about 170ish temp wise and doesn't seem to having any cooling issues. Is it possible the rubber fins just passed through the engine and out, or are they still in there somewhere?

Thanks in advance for any help.

 

[Kwilson0824]

Re: Bravo III impeller fins missing- what to do next?

 

[Rotorpilot1969]

Re: Bravo III impeller fins missing- what to do next?

I'm not certain the thermostat required temp on this setup but I'm sure it's a 160-170 thermostat. One thing to consider is the lake water is still rather cold. In the summer the input water will be warmer and could make or cause a motor to run a little hotter. Did the gauge ever drop dramatically below the 170 mark? The reason I ask is the sensor must fill the water or touch it. So if a gauge drops suddenly it's because there is no water present. I personally would put on a new kit and go boating. With the new pressure created from new impeller it could either help push it out or clog it up. Just keep a eye on your gauge and if it isn't broke don't fix it.

 

[dubs283]

Re: Bravo III impeller fins missing- what to do next?

My question is, how important is it for me to find the other two fins? Will the engine be ok if I'm not able to find them ?

What areas should I focus on looking?

you should find them, at least check the obvious areas - it will affect cooling for sure over time as other debris that passes through the pump may become more easily clogged with the impeller pieces there

check any and all oil coolers after the pump output and the t-stat housing, if any pieces made it past there they would most likely be small enough to pass through and out the exhaust

 

[Maclin]

Re: Bravo III impeller fins missing- what to do next?

This is definitely broke so it must be fixed. Those pieces will eventually cause problems. You are just lucky so far. The pic of that impeller would be pinned up on the really bad side of the Failed Impeller's Wall of Shame.

Do some more searches here, you will find that the pieces usually end up right at the exhaust manifold and thermostat housing. Best to do the needful now or soon you will have higher speed cooling problems in my opinion.

 

[Kwilson0824]

Re: Bravo III impeller fins missing- what to do next?

Thanks guys, I am going to try again tonight to locate the pieces.

Does anyone have any suggestions on how I can try to backflush the system?

 

[Bondo]

Re: Bravo III impeller fins missing- what to do next?

Thanks guys, I am going to try again tonight to locate the pieces.

Does anyone have any suggestions on how I can try to backflush the system?

Ayuh,... Disconnect the Output hose from the raw water pump,....

Move Up-stream to says the T-stat housin', 'n back-flush,...

Ya need to find All the missin' pieces,...
They'll be a Problem later if ya don't,...

Hopefully, All of 'em will come tumblin' outa the hose ya disconnected,...

 

[thumpar]

Re: Bravo III impeller fins missing- what to do next?

What Bondo said. Mine went out and I did just that to get the pieces out.

 

[HT32BSX115]

Re: Bravo III impeller fins missing- what to do next?

The boat is a 2004 I/O with a Mercruiser 350 Mag MPI and Bravo III drive, fresh water cooled. The boat is 10 years old and only has 34 original hours. Basically sat inside his airplane hanger on a trailer most of its life.

Yeah........that's where mine sits!.......... I don't think you have an oil cooler but you do likley have a power steering and possibly a "Cool-fuel" cooler.

When I got my 454/Bravo III the previous owner told me that he had changed the impeller. He didn't tell me that a previous failure or failures had resulted in 'lost' impeller fragments.

I found all of them though.......literally CRAMMED in the oil cooler. Since the oil cooler heat exchanger had pretty small holes, none of the fragments made it past ...... I had to use needle-nose pliers to get them out though. I can't see how any water got past them!

Your fragments possibly went into the main heat exchanger if the PS or 'cool-fuel' (if installed) coolers didn't stop them.

You need to find them..... Some heat exchangers have end plates you can remove.......you might find all sorts of 'stuff' in there!


Cheers,


Rick

 

[Kwilson0824]

Finally can post an update! So first off, i apologize I made an error stating my boat is fresh water cooled-ITS RAW WATER COOLED, I got confused between the two. Anywho, last week I went though the entire cooling system as best as I could. I 1) backflushed the cooling system from the main hose at the T-Stat....and nothing came out. 2) next I removed the T-start and checked for the rubber pieces in there...and nothing found. 3) I removed the cool fuel hoses and check in there, which has no screens or filters-just straight open pipe, and found nothing. 4) lastly I removed the hose going to the power steering cooler and found nothing in there and again it was straight open pipe with no screens or internal filters. So I feel pretty confident that I looked as hard as I could have but little unsure if it is possible of the pieces have exited out of the motor and are no longer in the boat. Remember the boat is 10 years old, 34 hours, and it's the original impeller. I'm thinking the impeller fins have had plenty of time to break down into smaller pieces and flow out of the engine. What do you guys think ? Could it be possible there not in there? Or should I check something else?