2002 AJ 5.0 w/ Bravo 3 overheat

M

MikeGagsAJ

New Member
May 29, 2018
6
Boat Info
02 amberjack
Engines
twin 5.0s w b3
I searched and searched and googled and looked some more -- but I need some help.
I have done ALMOST everything I can do while shes in the water...

Starboard engine is overheating.
Thought it was due to seaweed... its not.

Specs:
2002 Amberjack
Merc 5.0s - Raw Water cooled
Bravo 3
New mercruiser manifolds, risers and elbows replaced 6/16

port motor runs consistently at 170
starboard motor started running hot(er) - never got any alarms or never shut down.
at idle - runs normal - on plane - overheats within 20-30 seconds

changed the raw water pump on Sunday - the vanes were fine and looked brand new... replaced anyway.
replaced thermostat to a mercruiser 160 - same thing.

removed the hose going to the risers and very little water going into risers.
checked the port motor - A LOT of flow into risers.
removed the hose from the distribution hose on bottom right of engine - excellent flow.

I purchased a new circulating pump yesterday, and will be installing it this weekend.

I dont THINK its a riser or pickup problem, since the flow is GOOD up to the risers.
#20 is NOT clogged... i blew air and water thru..

what else am I missing ?

1613.gif
 
not sure if you've done this or not.....When I had this problem i unhooked the intake hose (the one that comes from the outdrive) from the raw water pump on both motors......the side that was "good" had water gushing in like a garden hose on full blast - the "bad" side flowed noticably less...."bravoitis" is the most likely cause of the problem
 
Oh yeah.
I don’t think it is bravoitis, since the flow is good FROM the raw water pump ...
And both engines pump the same

The “good” engine is the exact same as the “bad” overheating engine.


This is the good and bad engine flow - from/ to the risers.

 
Merc calls for a 1.25" ID hose to feed the raw water pump. Plumbing through BIII is ¾" ID. Now add a couple barnacles growing in the stupid pick up holes in the drive and you do the math.

Put in a 1.25" through hull, sea cock and strainer in line between engine and drive and problem solved. Do this in line because BIII still needs water flow (although less than engine) for cooling. Plus if you do it right you can build in a port to attach a freh water hose to for engine and drive flushing.

Henry
 
The video, while a good thought and could certainly help, doesn't tell the whole story, though. The reason is that the flow through the engine and to each of it's manifolds is not exactly the same from side to side. This is easily evidenced when you compare the temp (using your hand is all that's necessary) at the top of the elbow. Even with a perfectly healthy engine, it is not uncommon to find a difference in temp from one side to the other.

Before you keep throwing parts at it, let's start with some actual diagnosis. You haven't mentioned if you're in salt water, or not, but we'll go with that assumption for now (also, you should add your boat model to your info). First thing, let's verify that you are getting proper water flow by measuring the amount of water the raw water pump is pushing out. Pick a point from the output side of the pump to the input side of the water distribution housing (the later is probably the easiest). Now, crank her up, set the RPM to 1,000 exactly and collect the water into a container for exactly 15 seconds. Measure the amount of water. A Bravo pump should put out approximately 7.5qts. This should be done with the drive in the water as a hose doesn't usually supply as much water.
 
Lazy Daze said:
The video, while a good thought and could certainly help, doesn't tell the whole story, though. The reason is that the flow through the engine and to each of it's manifolds is not exactly the same from side to side. This is easily evidenced when you compare the temp (using your hand is all that's necessary) at the top of the elbow. Even with a perfectly healthy engine, it is not uncommon to find a difference in temp from one side to the other.

Before you keep throwing parts at it, let's start with some actual diagnosis. You haven't mentioned if you're in salt water, or not, but we'll go with that assumption for now (also, you should add your boat model to your info). First thing, let's verify that you are getting proper water flow by measuring the amount of water the raw water pump is pushing out. Pick a point from the output side of the pump to the input side of the water distribution housing (the later is probably the easiest). Now, crank her up, set the RPM to 1,000 exactly and collect the water into a container for exactly 15 seconds. Measure the amount of water. A Bravo pump should put out approximately 7.5qts. This should be done with the drive in the water as a hose doesn't usually supply as much water.
Click to expand...
Hello, thank you for this water flow test suggestion. i'm having the same issue described. But I've read and heard from other posts that the amount of water after 15 sec @ 1000 RPM is between 3-4.5 qts. not 7.5 ?? that is a big difference. Do you no for certain it is 7.5 ?? thanks. I'm going to run this test this week.
 
James Lee said:
Hello, thank you for this water flow test suggestion. i'm having the same issue described. But I've read and heard from other posts that the amount of water after 15 sec @ 1000 RPM is between 3-4.5 qts. not 7.5 ?? that is a big difference. Do you no for certain it is 7.5 ?? thanks. I'm going to run this test this week.
Click to expand...
The GPH spec will change depending on what drive we're talking about. Take a look back at where you found that other information and they're probably talking about an Alpha pump.
 
Lazy Daze said:
The GPH spec will change depending on what drive we're talking about. Take a look back at where you found that other information and they're probably talking about an Alpha pump.
Click to expand...
Thank you. I have a bravo III, I just came from boat as I’ve been trying to trouble shoot. I did remove hose T stat and ran engine for 15 sec. Plenty of water or at least I think plenty of water is getting to the t stat. Boat does not set alarm at idle but temp climbs at a steady pace. It got up to 168.

I checked the water psi per the smartcraft gauge and interestingly it is reading 0 at idle. I was able to pull the water temp sensor and clean it up real good. But it still reads 0.

I’m struggling for a fix. I have my new Harden pump coming Wed. I hope it’s that easy.
If I have some blockage due to impeller pieces. Where would be a good place to start looking. I tried back flushing but not certain if got all the hoses etc.

Thanks
 
Scott215 said:
I know on an alpha the power steering cooler is a good place to start
Click to expand...
Alphas and Bravos have the oil / PS cooler as the 1st stop for the pieces. The coolers usually stop about 90% of the debris.

Disconnect the inlet water hose to the cooler and you can usually stick your finger in there and feel around for anything. A borescope works very well there too, since it is impossible to get back there and look.
 
I have decent access on my 215
 
Ok folks, answer me this lol. If I disconnect the water inlet hose that comes from the transom to the water pump and I have good water flow naturally coming into my bilge wouldn’t this rule out Bravoitis?? I would think if my intake was clogged I wouldn’t see good flow coming in??
 
James Lee said:
Ok folks, answer me this lol. If I disconnect the water inlet hose that comes from the transom to the water pump and I have good water flow naturally coming into my bilge wouldn’t this rule out Bravoitis?? I would think if my intake was clogged I wouldn’t see good flow coming in??
Click to expand...
It could still be somewhat restricted and cause flow (think volume) issues at higher RPM's. Do the test as Dennis @Lazy Daze posted earlier in this thread.
 
James, how much time did you boat spend in salt water?

You may get ZERO waterflow, depending on the water level outside the boat.

And... if you did that test... and had water flow... are you basing your results on qualitative or quantitative results?
 
Lazy Daze said:
James, how much time did you boat spend in salt water?

You may get ZERO waterflow, depending on the water level outside the boat.

And... if you did that test... and had water flow... are you basing your results on qualitative or quantitative results?
Click to expand...

zero salt water, boat has been on Lake Ontario from 2005 to 2021 when I bought it. I’m the 2nd owner. It now is at Lake Erie. To my knowledge it has never been in salt water
 
James Lee said:
zero salt water, boat has been on Lake Ontario from 2005 to 2021 when I bought it. I’m the 2nd owner. It now is at Lake Erie. To my knowledge it has never been in salt water
Click to expand...
Bravoitis is from salt water use.
 
A buddy of mine had a similar problem so after chasing it for a while we took a piece of inch and a quarter hose from any home improvement store. We connected it to the pickup side of the pump and immediately could see the water flow difference. The end solution was thru hull water pickups and he never had a problem after that.
 
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