Spring Startup..no water circulating

R

roemere

New Member
Apr 13, 2013
50
IL
Boat Info
1977 SRV220 Cuddy
Engines
Mercruiser 888 (302)
Started boat for first time this season. Started up just fine but doesn't appear that any water is circulating thru cooling system. Had the muffs on but no water is discharged and water sprays out at muffs. Submerged outdrive in large tank of water, still no water discharged. Engine temp gauge stayed in green range for a good 20 minutes the started creeping up toward red zone. How can I tell for sure if water is circulating thru cooling system? What are possible causes for no circulation? No issues when boat was winterized.
 
I can't answer too much about your issue (I'm no mechanic), but I had a troubling overheating issue a year ago. It was caused by a buildup of zebra mussels in what I think was called the by-pass valve. It's parts 3 thru 6 in the schematic located in the thermostat housing. There's a couple spring loaded balls on a shaft. The springs were all caked full of mussels not allowing the balls to move. My application is a Mercruiser 5.7L/Alpha 1. This may offer you another place to look for cooling issues that wasn't considered.
 
Bob is right - lot's of lot's of threads to look through. But, pull your lower unit off and check the impeller/housing - that's a good first place to start.

The by-pass that Playdough mentions can be a source of problems, but it wouldn't negate water flow altogether.
 
Lazy Daze said:
Bob is right - lot's of lot's of threads to look through. But, pull your lower unit off and check the impeller/housing - that's a good first place to start.

The by-pass that Playdough mentions can be a source of problems, but it wouldn't negate water flow altogether.
Click to expand...

I agree with Dennis. Check the impeller first. It it hasn't been changed in a couple years change it anyway.
 
Not sure my ear muffs were supplying enough water, so we filled a 55 gallon tank, placed it under the stern drive and lowered the lower unit into the water. At idle, the temp gauge never moved after running for about 5 minutes and never saw any water discharge. Bumped the throttle up a bit (1500-2000 rpm) and then a flood of really black water filled the tank and poured out back by the transom. Also looked like exhaust was coming out by transom. I'm guessing the thermostat finally opened up?

Oil pressure is fine and gauge shows fine. Stopped the engine, pumped the dirty water out of the tank, refilled with clean water to try again. Am letting the boat sit a while first. Does the boat need to be running at a higher rpm before it really starts pulling water in? Does it need to heat up to a certain temp before the before the thermostat will open up to circulate the water?

When we still had the muffs on, if we rev the engine a little, the water spraying out around the muffs stops, like the engine is pulling it in...letting up on throttle, water sprays around the muffs again.
 
Water should ALWAYS be coming out of the exhuast ports in the transom assembly, regardless if the stat is open, or not, to allow circ through engine. Pull the lower unit and check the impeller.
 
Lazy Daze said:
Water should ALWAYS be coming out of the exhuast ports in the transom assembly, regardless if the stat is open, or not, to allow circ through engine. Pull the lower unit and check the impeller.
Click to expand...

Agree with checking that impeller even if it looks good heat from running it the first time could cause it to expand then seize up after a few hours of running (ask me how I know) CHANGE IT then carry as a spare. It's pay me now $50.00 or pay $5000.00 for a new engine. Sea water pumps are very easy to work on if you have any mechanical skills if not get a marine mechanic to change the impeller.
 
Mine is an "I-drive" stern drive (pre-Alpha 1)....what is involved in changing impeller and seawater pump? How much am I looking at paying to have this done?
 
I have never changed an Alpha impeller myself only a Bravo 2 that's mounted on the engine. There are a lot of you tube videos on your drive all alphas are very similar from what I've been told. Here's a link to a very good one it's very detailed has 2 parts. Mechanics in our area charge about $100.00 / hour for labor plus parts an impeller would probably be a minimum 3 hour job.

http://www.youtube.com/watch?v=tiCgHTrMKTw
http://www.youtube.com/watch?v=jXq35NOX8kw
 
Is my "I-Drive" the same as an Alpha? What are the differences?
 
roemere said:
Not sure my ear muffs were supplying enough water, so we filled a 55 gallon tank, placed it under the stern drive and lowered the lower unit into the water. At idle, the temp gauge never moved after running for about 5 minutes and never saw any water discharge. Bumped the throttle up a bit (1500-2000 rpm) and then a flood of really black water filled the tank and poured out back by the transom. Also looked like exhaust was coming out by transom. I'm guessing the thermostat finally opened up?
Click to expand...

That black water that came out once you bumped up the throttle was the remnants of your impeller that had melted due to overheating, finally coming in contact with water and ejecting the melted rubber. As your impeller was turning without any water flow, it doesn't take long for it to begin to melt at the tips, smearing the housing with melted rubber goo. The higher rpm probably was enough to pull up some water resulting in the black discharge.

In all cases, it seems to point to your impeller being bad, before you saw the water, and now especially after. Before it was worn out and not able to pull enough to get water flow at low RPM.

I've changed Alpha I Gen II water pumps many times, but never any older than that. Good luck!
 
Spot on...took it in for service and the verdict is impeller and housing...so far....
 
roemere said:
Spot on...took it in for service and the verdict is impeller and housing...so far....
Click to expand...


That should be all there is to it. The water pump system is pretty simple in these drives thankfully.
 
You must log in or register to reply here.

Forum statistics

Threads
113,357
Messages
1,431,076
Members
61,209
Latest member
96dancer250w454
Back
Top