overheating,new impeller no water out rear

Bayfisher Dave

Recruit
Joined
May 30, 2016
Messages
5
1989 Chris Craft 262 amerosport
Volvo Penta aq271c (chevy 5.7)

Hellos all, I am new here. I have a very Strange problem. I am not new to boats and I am a auto tech. Not master but I'm ok,lol.
Last year late in season, I had to change raw water pump because it took a dump. Clean everything and she ran and pumped well. 4 or 5 trips. Then I got sick and couldn't winterize the boat. It was last used in early August 2015 and always flushed with fresh water. This week I had to replace fuel pump and rebuild the carb (expected). I got the boat running on the muffs and I instantly saw no water coming from out drive lower port. She had only ran for about 2 or 3 mins before I **** her down and went to get new impeller. I removed the old one and instantly was puzzled because it was not even damaged at all! Puzzled I still installed the new impeller and then tried again. No water out rear still. I then disconnected all the hoses. Water runs free back through the tube at rear of motor/bell housing out the out drive water intake ports. Using the hose: water flows from that hose to the raw water pump. The pump does turn with motor and pumps out the port to heat exchanger. I put water hose to that port and water runs out the back of the outdrive. In other words I have no blockages and the pump seems to be pumping cause it wouldn't flow freely through the pump until engine starts. I have never had to prime this system before. I have no leaks while it's running and yet no water out the back so I will overheat. I am at a total loss on this. Plese, please help me out on this. I don't think there is much to overlook in this case. If risers were cracked, they would leak somehow, if they were clogged, I couldn't flow water through them out the rear,right? Please help
 
Joined
Sep 5, 2011
Messages
59
I have ruined an impeller and housing on muffs with my OMC. the water form the hose would rather go out the side of the muff then up to the pump. I'm just putting that out there lol
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
When you run on muffs, are you plugging the hole near the nose of the outdrive?
 

Bayfisher Dave

Recruit
Joined
May 30, 2016
Messages
5
I use the vp muffs. More rectangular than circular. But no I have not plugged the hole in the outdrive. I thank all of you. I will do that this evening and verify.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,297
VP muffs for your drive are held in place with a bungee chord.

http://www.iboats.com/Volvo-Motor-Flusher/dm/cart_id.226747351--session_id.340933799--view_id.484764

3673086c_4.jpg


you will need a cork or something to plug the lower hole. I have a tapered cap from a gear oil bottle that I use.
 

BRICH1260

Lieutenant
Joined
Jul 6, 2011
Messages
1,342
You probably have an air pocket in your water line and the pump is not priming.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
You probably have an air pocket in your water line and the pump is not priming.
You may have missed the part about plugging the hole in the nose of the outdrive...that's how these suck air on muffs,
 

Bayfisher Dave

Recruit
Joined
May 30, 2016
Messages
5
Intake hose clamp on top of outdrive rusted and broke on the bottom and difficult to see. Found it when it didn't overheat in the water.
 
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