2 Cool Fishing Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
134 Posts
Discussion Starter · #1 ·
I have a 1989 mercury 135 v6 outboard that has me puzzled. When there is a strong stream of water coming out of the tattletale, the motor runs right on H(ot) as indicated on the temp gage. The water coming out of the tube is steaming as well. At other times, there is weak/minimal flow coming out of the tattletale but I can run the motor wide open and only get up to 3/4 scale on the temp gage. I snipped the centers out of the thermostats (recommended by a merc dealer) and the motor is still running hot. Any ideas on what may be causing my problem? The water pump is 1 year old and there is probably less than 200 hrs on the motor.
 

·
Registered
Joined
·
58 Posts
Did you ever have a bad water pump? Broken pieces that got sucked up in the motor could be clogging passages, or some other debris.
 

·
Genesis 9:2-3 & Deuteronomy 12:15-16
Joined
·
21,162 Posts
I had similar thing happen to me as well. Turned out I need my thermostats replaced, water pump replaced, and water was in my lower unit that may have caused it to not be lubed as it should be and putting more work on the motor to run than necessary.

I then had the same problem again and it turned out my oil was not injecting into the fuel mixture properly so I now mix the oil in my gas. I knew the solution to my alarm going off was to NOT cut the wire and consider it fixed. I did it anyway. LOL
 

·
Gone Fishing
Joined
·
11,998 Posts
Snipping the center out of the stats will cause the heads to warp because the variations in temp through the heads expecialy in the winter months. Replace the stats and water pump impeller and change the popet valve. Those 3 things are the only things that will cause high temp. Blo air through all the hoses to check for obstruction. The stasts are rated at 140 degrees and normal operating temp is anywere from 170 to 200 overtemp alarm is set 220. And that is hot my friend.On the impeller the vaines need to be in a certan direction and this can be done by turning the shaft clockwise wile pushing down on the waterpump cover with the impeller in place on the shaft. You also need to put a bead of silicone between the exhaust chamber and the pump passage before you put the lowerunit back on. that will also cause temp to rise because it will draw water from the exhaust chamber.

hope this helps.
 
1 - 7 of 7 Posts
Top