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Name:	blmeanie -	Reply
Subject:	Engine running hot
Date:	6/23/2013 5:40:57 PM

So while out the last couple times the engine has been running hot, to the point of >180*, had the alarm come on. each time it has happened it cools right down very quickly. yesterday my neighbor and I replaced a worn out impeller and housing. Today same symptoms occurred. engine is : 5.7 EFI bravo II dual prop mercruiser. the engine runs at 140 or so in idle. what is next likely culprit to check on? I have heard the thermostat so far. The boat really never goes above 25 mph. thanks in advance.

Name:	CAT BOAT -	Reply
Subject:	Engine running hot
Date:	6/23/2013 7:20:19 PM

What condition was the old Impeller in???? Was there missing blades/pieces??? You may have stopped up coolers restricting water flow.

Steve

Name:	blmeanie -	Reply
Subject:	Engine running hot
Date:	6/23/2013 7:38:08 PM

I got similar advice from another forum. This is what was suggested: Replace the t-stat and find the missing impeller pieces. Should be in the heat exchanger behind the motor. BTW a Mercrusier outdrive with 2 props is a Bravo3. Do you agree? Do-able at home?

Name:	CAT BOAT -	Reply
Subject:	Engine running hot
Date:	6/23/2013 9:28:41 PM

Prolly would be a good idea to "back flush the system". Too much to type, but if you will call Prattville tomorrow, I will explain it to you. 334-358-2838.

Steve

Name:	blmeanie -	Reply
Subject:	Engine running hot
Date:	6/23/2013 9:33:13 PM

I appreciate that. My neighbor is the one that will be working on the boat, on Tuesday. I will mention this and if he has any questions I will have your number. Thanks again!

Name:	Osms -	Reply
Subject:	Engine running hot
Date:	6/27/2013 9:40:42 PM

You don't say how old the motor is, but you might also check the riser portion of your manifold. A common problem with engines that run in salt water, the riser begins to rust on the inside and the rust flakes off and blocks the water from exiting the engine causing overheating. The more common cause is as Cat said, vanes of the impeller break and usually lodge in the outlet portion of the pump housing with the Bravo II and III packages. If the motor is cooled via a heat exchanger, the heat exchanger may need to be cleaned with a chemical agent to boil the scale out of the exchanger.

Name:	HP HQ -	Reply
Subject:	Engine running hot
Date:	6/28/2013 12:28:30 AM

What about Bravo 1?? I love learning?

Name:	blmeanie -	Reply
Subject:	Engine running hot
Date:	6/29/2013 8:25:10 PM

Thanks for all the advice, got around to fixing it today. Neighbor called where we found lots of impeller particles more of a manifold than a heat exchanger. From the pump it was a chamber that water flowed through with four hoses in/out. It was about 6 inches by 3 inches in size. When we removed the hoses we found one opening that was virtually blocked with impeller parts, many more than we're missing from the impeller we replaced last weekend. Had to be from multiple impellers over time. Need to talk to my normal mechanic... Anyway, we skied after and the engine hovered at or below 160 consistently! Thanks again for the advice. Steve

Name:	Osms -	Reply
Subject:	All Bravo outdrives...
Date:	7/2/2013 4:58:56 PM

Seems you already know everything.

Name:	HP HQ -	Reply
Subject:	All Bravo outdrives...
Date:	7/2/2013 6:29:16 PM

I don't know everything, nobody does, but I was hoping to learn something, is that wrong?

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