Likes: 
Thanks: 
HaHa: 
Reply With QuoteYou could have pieces of the original impeller blocking water passages. Also check the thermostat.
Keeper
85 mercruiser 3.0
Last year I was out on the lake and had my boat over heat, after talking to a few friends and listening to there knowledge it was determined that the impeller and water pump had failed. So I pulled apart the lower unit and sure enough there was a big blob of what was my impeller. So I promptly changed it, sadly never taking it out the rest of the year.
Fast forward to a few weeks ago when I decided I was going to get my boat out. I proceeded to do the dewinterizing and start up and dumb me forgot to put the muffs on. End result toasting the impeller and pick up tube. I ordered the parts and replaced everything again only this time hooking the muffs up for the start up. After 15 minutes the temperature started creeping up past 160 by the time I turned it off I was at 200.
So my question is this, did I put the impeller in backwards? Is it the t stat? Or what I’m fearing is it the exhaust manifold? How can I determine what is going on for sure so I can stop wasting time and money? Is there a source where I can find diagrams or manuals?
Sent from my iPhone using Crappie.com
Super Mod and 2014 Crappie.com Man of the Year
* Crappie.com Supporter
You could have pieces of the original impeller blocking water passages. Also check the thermostat.
Crappie Wall Hanger II
Is your boat equipped with power steering?
I'd rather be fishing.
Keeper
Crappie Wall Hanger II
Ok, did you melt the first impeller or did it come apart?
I'd rather be fishing.
Keeper
Melted the first one, second one I melted the pickup tube
Sent from my iPhone using Crappie.com
Super Mod and 2014 Crappie.com Man of the Year
* Crappie.com Supporter
Here is a manual for an Alpha. Mercruiser 4 Cyl 3.0 Service Manual | Gasoline (85K views)
Fair Winds and Following Seas
Bill H. PTC USN Ret
Chesapeake, Va
Crappie Wall Hanger II
Ok. You've got several 'possibles' in play. I would inspect the following, 1) water pump base. 2) The plastic housing that the copper tube plugs into (that's located in the upper housing of the outdrive). And 3) The heat exchanger located at the rear of the engine.
It's still possible that the head gasket was compromised from the first overheat but most overheat problems on that system are caused by issues at the above locations.
I'd rather be fishing.
Keeper
Crappie Wall Hanger II
Top of bell housing. Will be smaller than the one in the pic. Inside is a honeycomb network and catches a lot of debris. If you shredded the impeller, it will be stopped up. Pull hose off that goes to transom connection and look in it from that end.
I'd rather be fishing.
