How hot is to hot?

[03silvers]

My circulating pump locked up which caused my serpintine belt to come off. This all happens while getting prepared to pull out at the end of the day. The alarm came on and I ran it for 10 more seconds to get to the dock at idle. Guage read about 225 degrees. Did I do major damage?

This is all a 97 mercruiser 5.7 with bravo one

 

[Yellow Yota]

Re: How hot is to hot?

Can't imagine too much real internal damage from 220*. Normal operating temp is 160 something, but look at cars. They use a very similar motor that usually runs between 185 and 205*.
Repair what you know is messed up and try it out. Check around the heads for leaks, and keep an eye on your temps. Also, check for water in the oil.

 

[03silvers]

Re: How hot is to hot?

Is a mercruiser really that similar to a car engine? I know my streetbike will run 215 all day long when it's hot out. But the boat normally runs 180. So 225 scares me

 

[airdvr1227]

Re: How hot is to hot?

Did I do major damage?

You'll know shortly.

 

[Philster]

Re: How hot is to hot?

Nope. 220 won't much matter at all. Mercruisers are Chevy engines, with changes for marine use. A car can run at 215... 220, etc, because they have antifreeze (which is actually anifreeze/antiboil).

A boat will vaporize the raw water at around 212 +/-, so a boat needs to stay below 200. Once water is vaporizing, the temps can go from 215 (no engine damage) to way beyond that really fast. That is the problem with a boat cracking 200 degrees. Then you have to worry about warped heads and the problems associated with it: water intrusion.

In the towing/trailer forum, all sorts of towing scenarios see truck engines run over 210 degrees. Towing big loads seems to produce 205-210 degree engine temps.

 

[03silvers]

Re: How hot is to hot?

So are you saying 220 was horrible or it might not have caused damage? I completly understand the coolant in a car vs raw water in a boat. Im going to obviously look for water in the oil and everything else. Just wanted to get some first hand knowledge of if i might escape outta this with just a new circulation pump

 

[achris]

Re: How hot is to hot?

Do a compression test on all cylinders.... Head gasket ok... You'll be fine...

The only differences between a Mercruiser and a car engine are, non-steel head gaskets, brass core plugs, spark arresting electrics (starter motor, alternator, distributor, etc) and exhaust manifolds.... Carbs are slightly different too, and no vacuum advance.... Oh, and that water pump you're about to replace

Chris.......

 

[03silvers]

Re: How hot is to hot?

alright, im attempting to order this new circulation pump. Here on iboats they have 2 diferent part numbers depending on if you have a steel or composite timing cover. Other sites say its all the same pump. So which is it?

Engine number 0k034204 i cant even find on mercruiserparts

Im also trying to find the cooling hose that goes from the thermostat housing to the port exhaust. But once again cant find the correct part number

 

[Simoniz]

Re: How hot is to hot?

Do a compression test on all cylinders.... Head gasket ok... You'll be fine...

The only differences between a Mercruiser and a car engine are, non-steel head gaskets, brass core plugs, spark arresting electrics (starter motor, alternator, distributor, etc) and exhaust manifolds.... Carbs are slightly different too, and no vacuum advance.... Oh, and that water pump you're about to replace

Chris.......

Also, car engine cooling system is pressuried whichraises the boiling temp of the water. Boat engines (open cooling) areonly pressurised as far as the feed water from the impellor (not much) so have to run cooler. That said, a momentary 220 wont have done any harm.

 

[achris]

Re: How hot is to hot?

alright, im attempting to order this new circulation pump. Here on iboats they have 2 diferent part numbers depending on if you have a steel or composite timing cover. Other sites say its all the same pump. So which is it?

Engine number 0k034204 i cant even find on mercruiserparts

Im also trying to find the cooling hose that goes from the thermostat housing to the port exhaust. But once again cant find the correct part number

Merc part# for the water pump is -850399 (and they are all the same, regardless of the timing cover). For the hose 32-860144 (that goes to the bottom of the manifold).

Chris........

 

[KermieB]

Re: How hot is to hot?

I agree that the Merc is just a Chevy for the boat, but an S-10 doesn't have a stern drive.

Here's what "COULD" have happened when you ran it hot. I've never taken apart a Bravo, but if it's closely related to the Alpha, the exhaust (and the heat that comes with it) ports out of the lower unit passing by the water impeller housing which is plastic and melts.

How do I know... I did it. It's not expensive if you are a do-it-yourself guy, but I had to change the impeller, the tube and the housing (which they call the water pocket housing.)

All this happened last year at the end of the summer, and the parked the boat, replaced the parts during the winter, and have taken her out at least 20 times this year and I have ZERO damage to the engine components.

 

[03silvers]

Re: How hot is to hot?

Chris, thanks! Im normally good at finding what i need but im still a little new to marine parts haha

I agree that the Merc is just a Chevy for the boat, but an S-10 doesn't have a stern drive.

Here's what "COULD" have happened when you ran it hot. I've never taken apart a Bravo, but if it's closely related to the Alpha, the exhaust (and the heat that comes with it) ports out of the lower unit passing by the water impeller housing which is plastic and melts.

How do I know... I did it. It's not expensive if you are a do-it-yourself guy, but I had to change the impeller, the tube and the housing (which they call the water pocket housing.)

All this happened last year at the end of the summer, and the parked the boat, replaced the parts during the winter, and have taken her out at least 20 times this year and I have ZERO damage to the engine components.

Thankfully the bravos raw water pump is a belt driven accessory off the motor.

 

[03silvers]

Re: How hot is to hot?

One more off topic question

I hit a piece of wood and it did minor damage to the leading edge of my v-hull. Its through the gel coat but barely nicked up the orange material underneath (fiberglass?) About 2 feet long, all on the front edge. Should i use marine-tex or a gelcoat repair?

Thanks!!!!

 

[achris]

Re: How hot is to hot?

Use either Gelcoat or 'Plasti-Bond'....