2003 DF40 Water Circulation Problem....HELP

[kirkprice]

Hey everyone. Have a real head scratcher here....

Decided to crank the boat up for the first time in about 5 or 6 month. Amazingly, did not even have to charge the batteries...just a few squeezes of the bulb. Purrs like a kitten. BUT, we have no water circulation.

First thought, impeller. Drop the lower, impeller looks OK. Pull the thermostat, looks fine. Ran water through the water lines, no obstruction. Put it all back together, still no water. If we put ears on it for water, at a decent amount of flow, we will get circulation (with or without the t-stat). So the lines seem to be fine. But, if we drop it in a tub (instead of the ears), we get nothing. So, i order a new impeller kit, thinking the other is just fatigued or something. New, impeller, gasket, pump plate and key. Installed. No change.

Also, when we turn the shaft when the lower is out, the shaft and prop turn fine. It just appears that no suction is being developed. Any clues anyone???

[Murray]

When your say no circulation are you referring to the telltale? Your not the first to make that claim on this forum, sometimes it’s no water out the telltale while using ears but works in a barrel, your issue is the opposite. Was the water pump in the barrel fully submerged, not the inlet, the water pump? Saltwater engine?

[kirkprice]

Yes...nothing out of the tell tale. Worked fine at the end of the summer. We had the inlets submerged by at least 3-4 inches below the waterline. No telltale in neutral or in gear. We have all the lines and everything seems to be clear.

[Murray]

Try adding another 3-4” on top of the 3-4” of water you already tried. When you were running on ears was there water coming out through the propeller? The telltale water exits out before it enters the block so basically all the telltale does is give you a visual that the impeller is in fact turning. Not sure how the DF 40 is plumbed but a common practice is to shove a weed wacker cord inside the telltale with engine running and work it in and out incase you have a blockage in that segment of the cooling system.

[kirkprice]

Well...here is the status. We took everything apart again, Found nothing obvious. Pulled water lines apart one by one and everything seemed totally clear. Cranked it up and still nothing. I have to head out of town for a few days...so my son gets p*ssed and takes it to the lake anyway for a test run. Telltale is spitting out like crazy. Not sure if our water level was creating an unknown cavitation or if we blew something out of a line...but it seems to be working fine. He took it out a second time in the thing is running like a top.

[Murray]

Glad to hear all is good. One thing I’ve learnt on this forum is not all engines will emit water from the telltale when using a barrel or muffs. Some will produce water in a barrel only, some with muffs only and some will produce water either way. With muffs I think it’s the quality and fit, with the barrel I think sometimes people don’t have enough water in the barrel.

[2014DF25ARS]

I had a similar experience after rigging my new DF25A motor. Ran it in a barrel after hanging the motor, and nothing from the telltale. I leaned that it is not sufficient for the inlet ports to be under water when starting the motor. The water level must be at the level of the impeller - which in my motor sits just above the break line for the lower unit, i.e. at the cavitation/ventilation plate. I conclude that the impeller, when dry, doesn't create enough suction to "prime the pump" when you start the motor. The impeller must be below the waterline when you start the motor, so the impeller is full of water. Once the impeller is pumping, then you can plane the boat to bring the impeller above the waterline (i.e. cavitation/ventilation plate at the waterline). This usually happens when your boat is in the water. But when you're starting in a barrel, it's natural to assume that you have enough water in the barrel when the inlet is underwater. Not so. I think when you put muffs on the motor, the water pressure at the muffs is enough to drive water into the impeller and prime the pump.