1996 5.7l EFI with Bravo 1 overheating immediately.

[thumpar]

I know I need to do diags but we are 2 hours from home and just want to get some ideas to brainstorm. We had the boat out 2 days ago with no problems. We decided to bring the boat to a company party on the river 2 hours from home. We get the boat launched and head out. We get a few hundred yards and I get an alarm. I see the temp is up and shut her down immediately. I open the hatch and no bad smells just hot. We get the blower going and leave the hatch open to get it cooled down. I raised the drive wandering if we had caught something covering the water intakes. It was clear. After 20 minutes I turn the key on to check the temp and it was normal ago and so I turned it on to see if the temp would rise at all thinking maybe some was clogging it and fell off. After 15 seconds it started to clime and I killed it.

Luckily there was a co-worker that had his boat out and we got a tow. I am not sure where to start other than looking at the factory manual and troubleshooting. It is just weird that everything was fine and then we take this trip and it seems to get no water. Would going down at 7% 6 mile grade have anything to do with it? I find it hard to believe but some of you gurus may know more.

Anyway, just looking for ideas. I will be looking into it tomorrow once we get home from the trip. Thanks in advance.

 

[HT32BSX115]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

After 15 seconds it started to clime and I killed it.

Howdy,


First thing I would do is look closely at the water pickup in the drive for blockage and then pull the raw water pump and inspect.

The most common cause of an overheat is a failed raw water impeller.

 

[MarkSee]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

That's just too weird if you're saying that the gauge would climb that fast after 15 seconds having sat for 20 minutes.

You don't mention if the boat is raw water cooled only or if it has a heat exchanger as that would also come in to play but if indeed it is just raw water cooled, needing only a screwdriver, maybe you could pull the raw water cooling hose before it enters the engine and see what kind of flow you might be seeing....or not to narrow down what could be the issue.

Mark

 

[thumpar]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

That is one of the things I was going to try. It is raw water cooling. When it went up after 15 seconds it was already at normal operating temp and when I saw it start to clime I killed it and got the tow. From the cold start it was about 10 minutes before the alarm. I am thinking there has to be a blockage and hoping I didn't toast the impeller in the process but likely. It is just bothering me and I can't look at it right now.

 

[Dslbrnr]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

That's just too weird if you're saying that the gauge would climb that fast after 15 seconds having sat for 20 minutes.

You don't mention if the boat is raw water cooled only or if it has a heat exchanger as that would also come in to play but if indeed it is just raw water cooled, needing only a screwdriver, maybe you could pull the raw water cooling hose before it enters the engine and see what kind of flow you might be seeing....or not to narrow down what could be the issue.

Mark

Happened to me....piece of the impeller from the raw water pump wound up in my water pump. Pulled water pump, removed rubber, and replaced raw water pump.

 

[achris]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

Stuck thermostat? It's almost too fast to be anything else.

Chris......

 

[HT32BSX115]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

Stuck thermostat? It's almost too fast to be anything else.

Chris......

I can run my raw water cooled 454 (with no impeller) and it takes a LOT longer than 15 seconds to even REGISTER on the temp gage!
None of these engines heat up that fast.

I would say that the temp indicating system could be faulty too.

But check the impeller and raw water flow anyway...........

When I removed and inspected my oil cooler after buying the (454) engine, (the previous owner told me he changed the impeller) I found the oil cooler so CRAMMED with impeller fragments and debris that I had to use needle nose pliers to get the pieces out! ....... "back" flushing would NOT budge them!

 

[thumpar]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

OK. We are home. I checked the thermostat in boiling water. When it hit 160 it started to open and when it got to 170 it was fully open, so that is working. Can I test the water flow to the housing on muffs and how long should I wait if I am not getting water? This is a cool fuel system if that makes a difference.

HT32BSX115: I think I misled you. The time it shot up like that is when I let it cool down to normal operating temp and started it again to see if I had caught a bag or something and it fell off. That is not from a cold start. From a cold start I would guess it was 10 minutes at just above idle that I got the alarm.

 

[HT32BSX115]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

OK. We are home. I checked the thermostat in boiling water. When it hit 160 it started to open and when it got to 170 it was fully open, so that is working. Can I test the water flow to the housing on muffs and how long should I wait if I am not getting water? This is a cool fuel system if that makes a difference.

HT32BSX115: I think I misled you. The time it shot up like that is when I let it cool down to normal operating temp and started it again to see if I had caught a bag or something and it fell off. That is not from a cold start. From a cold start I would guess it was 10 minutes at just above idle that I got the alarm.

Your T-stat is working correctly.

Even from "normal" operating temp, it wouldn't "shoot-up" to an overheat condx in 15 sec.

I would try it all again, but get yourself a infrared temp "gun' and point it at the t-stat housing (where the temp sender is located)

 

[thumpar]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

I could tell it really did get too hot. He is the way the event happened. I left the launch and idled out. Put it above idle to try to find the spot we were supposed to be going to. I got the alarm and shut it down when I saw the temp gauge. This was over about 10 minutes with the engine running. I open up the sundeck and could tell it was hotter than normal. I left it open to try to help cool it down. I kept turning the key on to see what the temp was once it got down to just under 175 on the gauge I started it again to see what would happen. When I saw it start to clime I turn it off. That was the 15 seconds period. It never went that far again, I just shut it down when I saw that it was not going to stay at normal temp.

I want to test to see if the impeller is pumping but need to know if I can do it on muffs, if I need a big bucket or if it has to be on the water. I have read that Bravos don't like to prime.

 

[HT32BSX115]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

I just shut it down when I saw that it was not going to stay at normal temp.

I want to test to see if the impeller is pumping but need to know if I can do it on muffs, if I need a big bucket or if it has to be on the water. I have read that Bravos don't like to prime.

If you haven't pulled the impeller yet, you need to do that now. Also, If your engine has a "Cool-fuel" heat exchanger, you need to ensure that it or the PS cooler (you probably don't have an oil cooler) is not plugged with debris.

Bravo pumps have a reputation of not being able to prime easily on muffs, but that just isn't true. You have pressure from the hose PUSHING water to the pump.

In the lake, the pump is just below the waterline. you'll know this if you ever disconnect the supply hose (while the boat is in the water) from the pump inlet and notice water start coming out of the hose.

Even if the hose goes above the water line, the pump will prime. These rubber impeller type pumps ARE positive displacement type pumps. They will produce a slight vacuum even when they aren't primed with water which will pull the water from the drive pickup.

They probably WILL NOT produce enough suction to pull water from a container of water that you put the drive in that *just* covers the water pickup.......the drive must be nearly submerged like it would be with the boat in the water......which would put the water line slightly above the level of the pump mounted in the engine.

 

[thumpar]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

Thanks for the advice. I will get into it tomorrow.

 

[thumpar]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

There is not much info on the seawater pump in the manual other than draining for winterizing. Anyone have a breakdown of taking it off or apart while still mounted? I have access to it but can only see it from a couple angles.

 

[MarkSee]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

You have the hard plastic water pump assembly mounted on the lower-front side of the engine right?

Here's a link from not too long ago and post #4 I believe is the process I have to go through:
http://forums.iboats.com/non-repair...maintenance-questions-622344.html#post4337454

I don't see your exact serial number but this diagram should be close for a breakdown:
SEA WATER PUMP ASSEMBLY (BRAVO ENGINES)-Performance Product Technologies

Mark

 

[achris]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

There is not much info on the seawater pump in the manual other than draining for winterizing. Anyone have a breakdown of taking it off or apart while still mounted? I have access to it but can only see it from a couple angles.

Arr, come on thumpar, you know the rules No serial number, no can help... :doh:

I'll do you a deal, you post a serial number and I'll email you the parts breakdown...
(PM me your email address)

Chris........

 

[thumpar]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

I added the engine serial to the sig. I will add the drive once I get back to the boat. PM inbound. Thanks.

 

[achris]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

I added the engine serial to the sig. I will add the drive once I get back to the boat. PM inbound. Thanks.

You got mail....

 

[MarkSee]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

I added the engine serial to the sig.

Based upon the serial number you provided, 0f791070, then the link I provided above would be correct for the parts list.
I guess right?????

Mark

 

[thumpar]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

I haven't got into it far enough yet. I am really hoping it is not that version and it the single piece body. I would be afraid to change of of the multi piece units while it is still in the boat.

 

[HT32BSX115]

Re: 1996 5.7l EFI with Bravo 1 overheating immediately.

I haven't got into it far enough yet. I am really hoping it is not that version and it the single piece body. I would be afraid to change of of the multi piece units while it is still in the boat.

FYI,


I just changed my raw water pump from the plastic model housing (which cracked for no apparent reason) to the stainless steel housing made by Hardin Marine Stainless Steel "Lifetime" Sea Pump Overhaul Kit - Hardin Marine

It's something to consider!

Not "cheap", but IMHO worth every penny!