Bravo 3 Cooling water pressure question

Thanks again all for the comments and suggestions. Espos4, not sure on the impeller part. I had the work done by the dealer and I didn't hear back anything related to the impeller other than it was replaced.

I'm going to try to figure out how to do the raw water pump test that LazyDaze suggested with the boat at idle and not on the flush system. Seems like that will at least positively confirm if any water is moving through the engine.

Perhaps I will be able to run it on the muffs also. Then based on that data I can move forward.
 
Not really familiar with the 350. General rule is, no or insufficient preload = low water PSI. High PSI is a restricted on output side of pump. Even with a scored pump housing you should be getting better pressures than you are describing. Since you are getting better pressure with the flush than in the water drawing through the outdrive, first thing I would do is check the tube at the transom. As opposed to a thru hull system, the outdrive has no real strainer, so what ever you may have gotten into will get sucked into the drive. May want to back flush the drive once you get the tube off. What may appear to be good flow, may not actually be enough to satisfy the motor.
Also, bravoitis, i have been there -done that, tends to set in overt the off season when everything has a chance to dry up and get hard. Normal water flow will not clear it out. On my 496s, they both had bravoitis at the start of last season after doing just fine at the close of the previous one.
Everything said above is all true, just process of elimination to figure it out. Start with the least inexpensive first. Changing the sensor would be one of the last on my list as once installed, its money spent. Since you are running warm and can see pressure changes between running through drive and flush tells me the sensor is working. Rule out all of the flow issues first.
 
So how do I do this test? Is it as simple as taking the hose loose and aiming it at a bucket? LOL

Probably makes sense to try this before changing the sensor.
Yup, that's pretty much it. It might be easiest for you to remove the hose on the downstream side (engine side) of the steering cooler (actually either side would work... but the upstream side you'll also need a barb fitting) and just get another hose that fits and use that.
 
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Heres another thought to consider. During the off season, Have you ever had the outdrive opened up to inspect the water inlet passage?

Once its removed from the boat, the oil must be drained, then its 7 bolts and the top half of the outdrive can be lifted off of the lower unit. This gives a clear view of the path that the raw water takes as it is drawn up into the boat.

After 6 months in the water here, I find a few barnacles inside on mine.
 
Well I stopped and picked up another set of muffs on the way home. Got the wife in the kayak and put them on the boat while it was in the lift.

Turned the hose on and cranked the boat and I'm getting pretty much the same results as I am with the outdrive submerged in the water. Water pressure is from 0 to 0.8 psi or so and the SmartCraft goes into alarm and puts the engine in limp mode.

If I put the flush kit on the pressure is fine at idle and rises and falls with engine revs. I saw as high as 11 psi at one point.

I'm thinking that I either have "early onset bravoitis" or there is some restriction in the sea water intake.

We did get in some pretty shallow water on our last outing, so maybe I sucked some muck into the engine that hardened up after it sat a day or two.

Espos4, I have never had the outdrives off. I have owned this boat (bought new) for just a little over 5 years now, and it has always been stored indoors in a shop until we moved in October of last year. We boated on a river that was fresh/brackish and I flushed the boat on muffs every time I used it. Now the boat is in a lift on the intracoastal waterway so it has never been stored in the water.

Any other thoughts or suggestions? Everything so far has been very helpful!
 
I just installed the fresh water flush kit on my boat last month. The flush kit, when installed according to the directions, tee’s the fresh water supply into the raw water pump supply hose about 18” from the transom inlet.

You state that you get good pressure and no alarms when running with the flush adapter supplied by a hose, but the alarm sounds when using the muffs or drawing raw water when the outdrive is submerged.

With a good impeller, the raw water pump is sealed and supplying the flush adapter with water and the engine off, all of the hose water will be pushed out through the outdrive, this should have flushed any loose sediment from the raw water intake. I believe you have a hard blockage causing your problem.

If this was my boat, I would first:
Climb back there and remove the plastic water neck from the transom inlet and inspect the inlet hose retainer for a blockage.
2 tough bolts to get to, but not impossible. Turning my steering wheel all the way left was very helpful. Raise the boat on the lift to keep water from flowing in.

If this proves to be clear, I would pull the outdrive, and open it up to check the water passages.
 
AA174814-8969-453A-92D5-C20DA027B903.png
Here’s a relatively clear one
 
Thanks again. The way this boat (and me, LOL) are made it would be incredibly difficult to access the transom inlet. But I think what you are saying makes sense. I will have to see if I can get to it. The engine is very deep in the hull. It was about all I could do to reach the pressure sensor on the power steering cooler.

That would about exhaust my capabilities honestly. I just don't have the time, tools, or patience to pull the outdrive. If it comes to that I'll be taking it to the dealer.

Any other thoughts are suggestions are welcomed.
 
Keep going with the plan to test water flow. Then post results and we can try and go from there.

I think I mentioned this above, but a key point that you had said was that you have been in fresh water up until late last year. That pretty much negates Bravoitis. I see zero reason to go and check out the piece going through the transom at this point.
 
Keep going with the plan to test water flow. Then post results and we can try and go from there.

I think I mentioned this above, but a key point that you had said was that you have been in fresh water up until late last year. That pretty much negates Bravoitis. I see zero reason to go and check out the piece going through the transom at this point.

I’m thinking it would be easier to pull off a hose at the thermostat to test flow since that is more accessible and rig up something. Thoughts?
 
Nothing new to report on this. Just didn't have time yesterday to get to it. I'll probably end up having to make a weekend project out of it. In the meantime, if anyone has a specific recommendation on which hose to take loose I'd appreciate it. If I can take a pic of the engine this evening I'll post it and detail out my water flow test plan.

Right now I'm thinking that I will take one of the hoses off at the thermostat housing, but I haven't tried to trace out the flow pattern yet.
 
Your engine has a different cooling setup than the older style. Use the power steering cooler.
 
man, I went and looked at the engine compartment again. It was all I could do the other day to get a wrench on the water pressure sensor and pull it out/reinstall.

I just don't think I'm going to be able to get in there and pull that hose apart. Looks like I'll be arranging a tow to the dealership to let them take a look at it for me.

Thanks all for the help!
 
Quick update....

I went and ran the boat on the hose again this evening. Let it flush plenty long and I actually started the flush with the outdrive raised, then lowered it when I got the boat down in the water.

Then I cranked the boat while on the flush and let it run. Pressure was great. Then I took the flush hose off and put some tape over the flush connection. My thinking was that the spring loaded check in the connection on the boat may have been sucking air. This time the boat was running at 1.0 to 1.8 psi at idle with the water coming through the outdrive. I could get about 3.5 psi with the motor revved to 3000 rpm.

What do you guys think about those pressures? Seems adequate to me but on the low side.

I think that this may be part of the issue. I'm still going to take the boat to the dealer to have them give it a once over for me. I'm thinking that I may have just lunched the pump impeller with some sand and muck.

Anyways, I'll post an update later when the dealer feels like they have resolved the issue. Thanks again for all the help. I have really enjoyed reading these forums over the years.
 
Update-

Dealer is saying they found a collapsed transom tube. They are also saying that they will have to pull the engine to replace it. Also quoted exhaust manifold replacement if they are found bad on inspection while the engine is out.

Total cost estimate a little over $6000 for all that. Ouch.
 
Shop around, that number is over the top. He should be able to replace that transom tube without pulling the motor.
Is this a trailer boat ? Salt or fresh ?
 
Thanks scoflaw, that's what I thought too. This happens to be the same dealer I bought the boat from new 5 years ago.

This boat has about 80 hrs on it. We moved to a salt location from fresh/brackish last October. The boat has always been in a lift or dry storage. Maybe 6 hrs put on it since we moved, if that.

The boat is trailerable. I'm thinking about just asking them what I owe to square up for the work already done and then shop around for a repair. There are lots of boats in this area with sterndrives so I'm sure I can find someone else to quote.
 

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