Cooling System

[pamlicobeach]

I have had a sudden loss of water flow from the indicator hose on my 1990, 115 hp Evinrude. The water pump is obviously a prime suspect, however, what may some other possibilities be. Is there a way to diagnose the loss of flow without removing the lower unit? As I recall, removing the lower unit on this engine can be tedious due to the shift linkage.

Looking forward to your suggestions.

 

[BaitThrower]

Re: Cooling System

Not sure for your particular engine, but I can at least check the water passages are not blocked by securing muffs firmly around the intakes and putting a little pressure in the water hose to drive the water up the leg and out the telltale on my engine.

Your best bet is to drop the leg and check the water pump too because if the water loss was sudden, perhaps the impeller shredded a piece and sent it up the water tubes and blocked somewhere. Blocked passages from salt exposure etc usually are a little more gradual.

 

[wilde1j]

Re: Cooling System

Why not check to see if it's overheating before taking drastic measures? The telltale just isn't that important.

 

[tashasdaddy]

Re: Cooling System

wilde1j, i totally and completely disagree, the tale tell is the indicator that the water pump is pumping, no tale tell, no cooling at all. although, the tale tell does not indicate that the thermostats are opening and cooling the motor.

pamlicobeach, try running some weedeater line, up the tale tell outlet, it could have a critter nest in it. if this does not clear it. time to drop the lower unit. if the impeller is toast, fine all the pieces, even if you have to pull the thermostat and back flush.

 

[Dhadley]

Re: Cooling System

Wilde1j is 100% right. The overboard indicator can be totally plugged up and the motor may be fine. That's just an indicator, when it quits you need to verify the motor temp. It may well indeed be fine. It may or may not have quit pumping. If the hot horn has not sounded it's probably just a plugged indicator line.

It also has nothing to do with the t-stats. The overboard line can be flowing and one or both t-stats could be stuck shut or open. It can be plugged and both t-stats be operating just fine.

The bottom line is, just as Jim suggested, if the line quit flowing it's time to verify the engine temp.

 

[emdsapmgr]

Re: Cooling System

The telltale nozzle in the cowling is a restrictor and will occasionally plug up with debris. You can apply compressed air to the nozzle and blow back into a running engine. If it plugs up again, remove the telltale hose from the back of the nozzle and run a small wire through it. You can also temporarily run the engine with the other end of the telltale hose removed from the block. You should have a strong, steady stream of water coming out the block telltale fitting. Make sure the restrictor and telltale hose is reassembled before operating.