Mercury peeing problem

[sherman brown]

On 9/15/2023 at 11:29 PM, Crestliner said:

I'm sorry.  but whole conversation has been a blast.  But I must have been talking about the wrong pee hole ! And by the way milkyman the impeller speeds up and slows down with engine RPM.!!!  Its running off frickin drive shaft!!!and that time it takes to start peein. is the t-stat opening!!!! all 6 of my outboards work that.  Mine are all big 2-strokes even honda 8.8 kicker 4 stroke . Maybe different for new 4 stokes don't know don't have one don't care either.  How did I come to this conclusion? mud bugs plugged up both T-Stats started motor no pee. Took apart both t-stats cleaned water channels and housings. put back together no it pees  aaaaaaaahhhhhh

 

 

I have to disagree with you about the thermostat opening before the water comes out of the pee hole. the motor has to reach operating temperatures of about 150 degrees before the thermostat opens and that takes much longer than it takes for water to come out of the pee hole. the pee line is there just to let you know water is being pumped. on many outboard motors, the water starts almost as soon as the motor starts up. I haven't ever tested it but I believe if the motor was cranked over for a minute or a little longer water would start coming out.

 

why don't a lot of you guys that believe the water out the pee hole is dependent on the thermostat opening just Google the route of the pee hole on outboard motors and see what you get? the lines run against the exhaust plus I believe it even flows with the exhaust heating the water much faster than the motor heats up enough to open the thermostats.

 

I don't want you to feel like I'm attaching you because all this is from what I've read and is totally my opinion and that's all.

 

in your case, you are jinxed. it is very rare anything large enough to stop up the thermostats would ever get past the screen on the water pick-up or be deep enough to get in water pick-up on the lower unit. but I will never say anything can't happen. but even at idle the pump is pumping more than enough water to keep the motor cool if the impeller and upper housing are good. if it overheats even at idle something else has to be wrong.

 

the worst I was ever fooled was after smoking my impeller I replaced it. at idle or slow speed it cooled just fine. but if I went over 3/4 throttle i could watch the heat hand rise. I took it back down and made sure a piece of the old impeller hadn't stopped up a water line I cleaned them from the back to the motor. put it back together with another new impeller, and it still overheated at higher RPM.

 

I was asked by a friend who runs a charter and worked on boats in his spare time if I had changed the housing after telling him I smoked the old impeller while working on changing the carb from a 2-barrel to a 4-barrel with an adaptor plate and forgot to turn the water back on we started it up and revved the motor a few times before someone noticed we had no water.

[Crestliner]

well then what?

[Mikeyman104]

Different things learned while trying to do this: 

1. The speedometer tube is a pain to get back into it's little hole once you drop the lower unit 

2. Make sure the shift shaft goes back into where it's suppose to. Launched the boat this morning and the lower unit was stuck in forward gear. That was quite a jolt at the dock and glad the ropes held. Shifter was in neutral so she started, but I dropped the lower unit while in forward and then missed it going back in, so gears were in forward, but shifter in neutral. 

3. I shouldn't quit my day job to be a mechanic.  

 

Now I got a constant beep above 2500ish RPM and she still takes quite a while to start spitting water, so probably going to just take it to a dealer. Thinking it has something to do with the cooling system cause I've botched this project haha. I was always under the same impressions as some of previous comments in that as soon as it starts it should have water coming out. It still doesn't for me, so might be poppet or thermostat? Getting to the poppet looks like a pain, but might give the thermostats a quick look before I take it in.

 

Thanks all for the inputs and help on this. 

[sherman brown]

9 hours ago, Crestliner said:

well then what?

 

if you will just google it you will learn the pee hole is just a bypass line that doesn't have anything to do with the cooling it's just to show the water pump is pumping water. if the stream is low the first thing is to make sure the line isn't stopped up. if it's still a small weak stream then the next option is the impeller is probably not pumping water like it should. most motors start peeing almost as soon as the motor starts. at idle it should still be a healthy steady stream but when the motor is revved up the stream should get very strong and go out farther from the motor. all the water the pump, pumps doesn't flow into the motor as the thermostats regulate the amount of water it needs to get the motor up to temperature and then keeps it at that temperature. if they let all the fresh cool water in the motor would never get up to temperature. the back pressure is why more water flows out the pee hole.

 

back when I was a young man and racing cars we just removed the thermostat so more cool water was flowing through the motor. it never even got up to operating temperature even when it was on the track. there was nothing to slow the flow to the motor and let it get up to temperature. the thermostat serves the same purpose in an outboard motor.

 

the water coming out of the pee hole never enters the inside of the motor but gets hot fast by the exhaust.

[LongLine]

Sherman  - exactly!  

[Mikeyman104]

Most recent update: took it to a shop and they replaced the water pump and thermostats. Pumps water good about 5-10 seconds after start up, but nice solid flow now. Much better compared to when I bought it. 

 

Best part was the guy told me it looked like someone replaced the impeller with a cheap one that is way more flexible than the OEM version. I told him, yeah I did that, and that's when it all went down hill . Think I'll pay for the OEM parts from now on just for that peace of mind. 

 

Thanks again to all for the comments and feedback. 

 

 

[stinger]

This is a good thread Mikey. A good learning moment for us marine mechanics.  Got a lot of milage out of it.