Hello folks I bought a set of muffs, turned on the hose, got really good pressure, and still no water will come out the "pee" hole when I run the engine. Not sure where to go from here. Suggestions? Thanks! Markbano
Hi Mark, When you say that you got good pressure, do you mean water pressure on the gage in the boat? How long did it take to register pressure on the gage in the boat? If the gage in the boat registers pressure, then the pump has water and it will not be damaged by lack of water. How long did the motor run? I have never seen a cooling diagram for a 3 liter. The cooling water on a 2.5 goes from the pump up through a central passage, then down through cooling passages in the exhaust chest cover and into the block. When the block gets full, water can flow down through the heads and up through the thermostat bypass, and will reach the tell tail passages. The block holds several gallons of water and it takes a couple of minutes to fill at idle. If no pressure is registered on the gage in the boat, it could mean the pump is dry and that will damage the pump in a few seconds. jim
Jim I didn't look at the gauge on the boat. However, I'm sure it was zero. I ran the motor for a good 30 seconds with good water pressure in the hose (i.e., it was trying to squirt out around the muffs. There is a slight squeal sound coming from the motor. I'm suspicious that the impeller might be stuck or something. Would that prevent water from getting through? I'm really nervous about continuing to mess with this. I guess I"m probably going to have to bring it to the dealer, which is going to be inconvenient this time of year because I've got the boat packed in behind a bunch of other stuff. I could pull the lower unit off and take a look if you think that would be the way to go. How long can I run the engine without water coming out the "pee" hole before I endanger the engine? Thanks Jim!
I don't think you ran it long enough for the block to fill. Water not coming out the tell tail is not a problem for a couple of minutes. You can put you hand on the top of a head and feel if it is getting too hot. Running the pump dry is a problem in a few seconds. Are you sure your muffs are completely covering all of the intake holes? If it does not cover all of them the pump can suck air and not pump. jim
Yes. The muffs are completely covering. But the slight squealing sound I've heard every time I start the engine and my thought is that the impeller might be bad. If the impeller is bad, will it stopp water from going into the engine cooling system? My gut tells me that it just isn't filling at all. I ran it twice. Nothing has ever come out. With the hose pressure I wouldn't think it would take too long.
I don't have any Optimax experience, but I would guess that the squeal is the air pump. Are you running it with the cowl off? The hose pressure has very little effect on the water pressure or the flow through the pump. The pump in that case will slow the water down and cut the pressure. At idle on the hose, I would guess that your pressure will read 5-10 pounds in the boat. If it were mine, I would let it idle for a couple of minutes. If you do that and the pump is dry for some reason, you will have to replace the impeller. At least you would have the answer for sure. jim
You are welcome, I always suggest that the motor be run on the trailer in the lake because it is less stressful to a new owner. You do not have that option now. Replacing the impeller is suggested every year by Merc. I think a 3 liter can go two years in clean water. Replacing it yourself is way cheaper than taking it to a dealer to be winterized. jim
My impeller sat for a long time because this was a new in the crate 2002 engine, which had a 2006 powerhead installed before it was ever used. So... the impeller is old. I was running the engine with the cowl off. The squealing noise I don't recall hearing previously
I would replace the impeller before running it in the lake. You don't have anything to lose by running it on the hose for a couple of minutes. I would also order a manual now for a 2006. I know they are expensive, but you will need it to replace the impeller. The 3 liter impellers are big and flexible, but as you say yours is old. jim
