1966 Merc 500 not peeing

[joeaverage9]

Hello again. I got her to run excellent so I replaced the water impeller to be on the safe side and it was in like new condition but went ahead and replaced it anyways. When I run the motor in my driveway with the water hose attachment it has water coming out of the vents just above the prop. It comes out warm and the piston top is very cool to the touch/ not hot at all. I let it idle for about 8-10 mins and thetemp of the top remains cool. The pee hole never spits out a drop of water though. I removed the hose of the pee hole nipple and tried to blow air with my compressor with no success ( blows my nozzle right out of my hand. I also tried the water hose with same results. My question is does the lower unit have to be off for the air pressure or water that I shot in the hose to escape or does the motor need to be under load for water to come out of the pee hole? I revved it up quickly but nothing. Joe

 

[joeaverage9]

Re: 1966 Merc 500 not peeing

If I took a lap around the lake what what should the temperature of the piston top be if I use a infared/ laser thermometer? How do I know if its overheating?

 

[matt167]

Re: 1966 Merc 500 not peeing

You should have a mist of spray out of the exhaust ports at idle. If you have that, chances are the tell tale is plugged up and you can unclog it with a peice of wire and see if it starts peeing. If not, replace the impeller. By the time you find your motor is too hot, it is arleady cooked

 

[GA_Boater]

Re: 1966 Merc 500 not peeing

So the impeller is new and you blew through the tell-tell hose. Find the other end of the hose, detach it and probe the port with a piece of wire. You may be blocked there.

Also, are you sure you have a tell-tell? My '66 500 didn't until I added one.

 

[joeaverage9]

Re: 1966 Merc 500 not peeing

I THINK its a tell tail GA. Looking at the motor from the prop side the hole is under the bottom right legde about 2" from the bottom chrome molding. The hose goes to the bottom left of cyl#4/ (prop side) . Maybe its a freaking breather? Don't know man. My experience is with tuned cars, sport bikes, dirt bikes and one jet ski. Everyday I read post from you guys. Knowledge is power( and keeps the wallet fat). Thanks for the input.

 

[Aqualift]

Re: 1966 Merc 500 not peeing

It's the tell-tale, not a breather. My 68 Merc 500 had blocked water passageways in the exhaust cover plate. No amount of compressed air or probing would get it to pee. (pressure washer too) I ended up having to remove the powerhead get the exhaust cover plate off. I found a bunch of sand stuck in there from the previous owner.

No, you don't have to have the lower unit off for water or air pressure to escape.

In addition to a water pressure gauge, I placed a thermistor next to the No. 1 spark plug to monitor temps of the cylinder block cover. I can watch the temps go down as water pressure increases. The other day, lake water temp was 65F and at WOT I was seeing temps of 93F.

 

[joeaverage9]

Re: 1966 Merc 500 not peeing

Whats a thermistor? Is it a Temp readout? I would like to find some temp and pressure gauges that matches the 66' era of my boat. Im keeping her as original as possible. I ran the boat in the lake today for over 4hrs.Boat ran AWESOME and got alot of looks too. I followed the advise someone gave me here and removed the 1/8 plug at the top of the block and it was shooting water up big time at idle. . Too bad nobody has invented a product to brake up that sand without damaging the seals and gaskets in the engine. Im hooked on boating. Looks like my bimmer is gonna get less attention for a while.