1985 Mercury 150 Tell Tale Questions

DixieBoatN

Seaman Apprentice
Joined
Mar 17, 2009
Messages
41
I am brand new to these forums but have been lurking a little. I just purchased a boat with a 1985 Mercury V150 XR2 motor. I have a Clymers manual (I know it is junk) and plan to purchase a Factory Service Manual soon. I am new to outboards, but I have extensive mechanic experience in the automotive arena.

My question is am I supposed to always see water coming out of the tell tale? I took the boat out yesterday and I do not recall if it was coming out right away, but shortly after getting it off of the trailer and before I gave it much throttle I did see water coming out. I ran a short distance, turned around and came back and when I got back to the dock it was not coming out anymore, so I shut the engine off. It was a rather cool day and the lake water is still cool. The previous owner stated that the water pump impeller was replaced within the last 6 months. I put it on the cuffs today and when I fire it up, no water comes out, but I did not let it run for longer than 60 seconds.

I used some nylon line from my string trimmer and pushed it into the tell tale spout until it hit a bend it could not get past and did not notice any obstruction. I shot water into the tell tale and noticed it flowing out of what looks like weep holes on the bottom side of the cavitation plate directly above the prop. I also checked the original Operation and Maintenance manual (yep, that was with the boat!) and it only says that if you see no water coming out of the tell tale, shut the motor off immediately. I guess this would imply that it is not controlled by a thermostat?

I never heard an alarm, but I also have not tested the alarm to make sure it works yet. I have searched the forums and have not found anything that answers my question, so I appreciate any assistance. I will also search for the alarm circuit test procedure and test the alarm module.

Thanks!
 

yamamarinetech40

Petty Officer 1st Class
Joined
Dec 17, 2006
Messages
328
Re: 1985 Mercury 150 Tell Tale Questions

You should always have water coming out....sometimes tough to do on muffs, but in water it should always pee....take it in for new impeller...
 

yamamarinetech40

Petty Officer 1st Class
Joined
Dec 17, 2006
Messages
328
Re: 1985 Mercury 150 Tell Tale Questions

Wait, i should mention, on a lot of mercs(i'm a yama guy) the peeing IS controlled by thermostat, but you said when you came back it wasn't peeing, but then you said water was cool in lake....does it pee at startup? Before warmed up? If it does, then it should pee ALWAYS....if it is off thermostat, you need to get or borrow a temp gun and check the head temps while running in water and see if getting hot or peeing when temp is up....and check the termostats, they're cheep.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 1985 Mercury 150 Tell Tale Questions

A lot of the V6 motors only have a telltale when the thermostats are open. If you remove the cowling, you should see the hoses comming off the heads. they should connect and supply water to the telltale. The thermstats are usually under them.
 

hkeiner

Lieutenant Junior Grade
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Oct 17, 2006
Messages
1,055
Re: 1985 Mercury 150 Tell Tale Questions

On my 1996 150hp V6, the water does not flow out of the tail tale when the motor is first started when cold. It takes a minute or so before it warms up enough to start peeing. After that, however, it pees constantly.

As a side note, I installed a pressure gauge on my motor because I had similar concerns about timely peeing and having to worry about a motor failure if the water flow stopped. It is an easy installation and it brings much peace of mind because you can monitor the water pressure constantly. Below is a link that describes how to do it.

http://www.diy-boat.com/index.php?option=com_content&task=view&id=151&Itemid=49
 

DixieBoatN

Seaman Apprentice
Joined
Mar 17, 2009
Messages
41
Re: 1985 Mercury 150 Tell Tale Questions

Thanks for the responses.

Judging by the hose routing and tee fittings, I would think it would pee all the time. There is a right angle fitting coming out of the bottom of the motor on the port side and that runs back to a tee with one side going to the top of the head on the port side and the other line feeding the tell tale. The starboard side head is fed from the line going to the port side head. I am not sure what there is between the pump and the first fitting that I can see.

I am going to drop the lower unit off of it anyway and just be sure. I am going to pick-up an impeller and gasket kit tomorrow and check it this weekend just to be safe. It only concerns me that when we returned from a quick run it had stopped peeing. If not for that, I'd drop it back into the water and see what happens. I can't say for sure that it was cool enough outside and the lake water was cool enough to close a thermostat on the short run. I'm just not confident that there is not something wrong with the pump. Call me paranoid.

On a side note, I see a temperature sending unit on the starboard side head with a wire attached. I see a similar temperature sending unit on the port side head, but no wire attached. Is it not supposed to have a wire attached or is it a factory installed sender for a dash mounted temp gauge?

I also found a link to the Oil Injection alarm info that everyone might find useful --> here

I will also look into installing a pressure gauge on the cooling system for my peace of mind... IF that is something that is actually achievable, but that is a topic for a different forum. ;)
 

DixieBoatN

Seaman Apprentice
Joined
Mar 17, 2009
Messages
41
Re: 1985 Mercury 150 Tell Tale Questions

I was looking closer at my water flow diagram and I realize that the tell tale is POST thermostats on this motor, so it would make sense that no peeing would occur when the motor is cold. The fitting going into the lower port side of the motor is the discharge, hence why I saw water draining out of the holes above the prop when I shot water into the tell tale.

I am going to replace the thermostats and poppet/idle shutoff valve for good measure and put it in the water with my infrared thermometer in hand and let it idle a little and see what happens before I drop the lower unit to mess with the water pump since the previous owner stated that the impeller had been replaced recently.

The reverse gear is out on my lower unit, so I will be trying to find a gear for it and when I have that to replace, I will swap out the water pump impeller again for good measure. I am finding out that the reverse gear can not be purchased as a single gear. You have to purchase an entire prop shaft assembly!!! I am hoping to find a good used reverse gear or even a good used lower unit for cheaper than buying the entire prop shaft assembly new.

I can't find it listed anywhere. What is the operating temperature range on this motor? What are the thermostats set to open at?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 1985 Mercury 150 Tell Tale Questions

Thermostats on outboards usually open at about 140*F. The motor will operate in that range a slow speed and run a bit hotter at speed.
 

Toxarch

Seaman
Joined
Aug 15, 2009
Messages
61
Re: 1985 Mercury 150 Tell Tale Questions

Thermostats on outboards usually open at about 140*F. The motor will operate in that range a slow speed and run a bit hotter at speed.

That's good to hear. This is my first outboard (used) and the tell tale temp seemed hot to me. The termostats looked fine when I pulled them and they open up after about 30 seconds on the muffs at idle. I thought I would test the temperature before posting about it. The temp holds at 142 to 143 degrees at idle on the muffs. I am going to assume that is good because I want to wait until winter (whenever that is in Texas) to change out the impeller. I have a new set of thermostats in case the old ones go out.
 

Gary Lee

Cadet
Joined
Aug 14, 2011
Messages
12
Re: 1985 Mercury 150 Tell Tale Questions

If it is anything like my '86 150, it is kind of hard to tell if it is "peeing" I used to have a 50 hp merc that had a direct outlet that shot a single stream away from the engine, but this 150 sort of seems to be more like a splattering of water which is harder to see, just sort of splatters around out the back-not a strong, steady stream like the old 50 hp motor. I was worried about that too when I first got this one, but I think it is normal, at least it seems to be in my case. Other more knowlegable people on the forum might have a better explanation.
 

hkeiner

Lieutenant Junior Grade
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Oct 17, 2006
Messages
1,055
Re: 1985 Mercury 150 Tell Tale Questions

I will also look into installing a pressure gauge on the cooling system for my peace of mind... IF that is something that is actually achievable, but that is a topic for a different forum.

I would say to definately install a pressure gauge. Much better that watching for the pee stream or waiting for an alarm to sound before you realize there is a problem with water pressure. You also have more constant peace of mind checking the gauge on the dash when running the boat. I installed one on my Mercury 150 and it was easy to do and not very expensive. Search this forum and you will find several posts on this subject along with a link to a step by step how-to do it.
 
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