140 HP Merc Cruiser Overheating

[Benny Two Time]

The engine is strong, good compression, starts fine, idles fine. <br /><br />It's only when I give it a little gas that it starts to over-heat. Every single time. <br /><br />It cools off when I slow down, and when I go to accelerate it gets real hot. I've had the impeller replaced, and the cooling system flushed out, and that did nothing for my problem. <br /><br />Any suggestions would be greatly appreciated.

 

[tystick]

Re: 140 HP Merc Cruiser Overheating

Sounds like improper water flow volume at higher speeds not able to keep up with increased engine temp.<br /> Possible obstruction - rust/corrosion - elbows shot etc.

 

[tommays]

Re: 140 HP Merc Cruiser Overheating

Have you done the basic thing like change the Thermostat ?<br /><br />If your sure the pump is good there are places like the water hose in the transome that can restrict water flow comeing in<br /><br /><br />The next problem is water flow OUT of the motor the manifold and riser CLOG when they get OLD <br /><br />

<br /><br />The only way to be sure is to drain it and pull the riser and check it<br /><br />tommays

 

[Benny Two Time]

Re: 140 HP Merc Cruiser Overheating

I had a mechanic suggest that to me. <br /><br />With the engine only being 2-3 years old. Do you still that's the problem?

 

[Bt Doctur]

Re: 140 HP Merc Cruiser Overheating

did this happen to start after an impeller change or was it a problem before.

 

[Don S]

Re: 140 HP Merc Cruiser Overheating

Lets get some info here Benny<br />Obviously your engine is only 2-3 years old, but how old is the manifold and riser and the rest of the boat. Including the outdrive.<br />Since you are calling it a 140, I know you aren't reading this off a 2003 or 2004 boat.

 

[Benny Two Time]

Re: 140 HP Merc Cruiser Overheating

Bt Doctur - This happened before and after the impeller change. <br /><br />Don S - The Boat is an 83 Webcraft. I'm pretty sure the manifold, riser, and outdrive are the original.<br /><br />The guy who sold me the boat said that the engine he had in there before overheated and blew. So I'm thinking he was experiencing the same problem with the previous engine.

 

[NorthOfDallas]

Re: 140 HP Merc Cruiser Overheating

Did you backflush the system from the Thermostat when you did the Impeller?

 

[Benny Two Time]

Re: 140 HP Merc Cruiser Overheating

yes the system was backflushed at that time.

 

[Benny Two Time]

Re: 140 HP Merc Cruiser Overheating

Looks like it's the Elbow. <br /><br />The Elbow was alowing water flow only when there was water pressure, due to build-up. <br /><br />I have the part on order and should have it sometime this week. <br /><br />And to think I paid two mechanics to figure this out. <br /><br />Thanks for the tips you guys. It's greatly appreciated.