DT115 Hot Cooling Water

[Marion Moore]

DT115 ?96 EFI ? Used, I have owned it for one year.

Saturday while running on muffs, I noticed that steam was rising from the tell tale water as it hit the ground. I touched the water with my hand and it was almost hot enough to burn you. No alarms. I cut the engine and felt the cylinder wall, it was almost too hot to touch.

I opened the water passages to find that there was a fair amount of corrosion and no anode. I have ordered an anode and cleaned the corrosion as best I could. I looked at the water pump and it is in great shape. None of the passages are blocked.

I have touched the tell tale water while boating and noticed that it seemed hot but I would expect it to. I have had the over temp alarm to go off in the past so I replaced the cylinder temp sensor and thermostat. Two trips later it alarmed again. Funny thing is I can shut the engine down and restart and it usually goes away.

I?m clueless here. What would cause the tell tale water to be HOT. Is it possible that I?m not getting enough flow with the muffs and the water is not making it to the top of the motor? The temperature alarm is bugging me too. Other than that and the worst fuel economy of any outboard ever produced it is a great motor. Any genius would be greatly appreciated.

 

[hopalong]

Re: DT115 Hot Cooling Water

If you go to www.brownspoint.com and click onto your engine model no. and view the lower unit of your engine you will see there are "two" intake water pick ups. The lower one is on each side of the unit above the gear area while the upper one is under the cav plate just above the prop. From the illustration follow the tube that goes to this intake.There is a plate and seal were the tube protrudes horizontally into the area just before the pump. That plate will warp overtime and cause the area to suck air into the pump/water flow. Your pump may be ok but if this plate/seal is bad the water flow wont be without air and usually causes poor water flow and thw water to be abnormally hot.
Just a thought.
Look at part 13, 14, and 19 http://store.brownspoint.com/dt115/fig045-1158601.asp

 

[Marion Moore]

Re: DT115 Hot Cooling Water

Hopalong,
Thanks for the comments. I replaced the exhaust plate and shield about 8 months ago when I reworked the lower unit. Just to be on the safe side I sealed around the water pump housing before I reinstalled the L/U yesterday. I didn't think it would hurt.

 

[hopalong]

Re: DT115 Hot Cooling Water

Refering to "water passages" did you check the water passages through the heads? If not you may have some debri in those passages that may cause intermittent hot warm issues. Did you know that the upper head to the lower head has a stainless steel tube (thru a grommet) located at the outer lower ends of the heads where they join that circulate the water to and from thru the heads? This is the passages that I'm refering to.
Also check the thermostat, it may be sticking or weak. If you do remove the thermostat cover to check the thermostat be careful when removing the small retaining bolts that could be corroded and may break off. Once if you do remove the thermostat you could also run a water hose to help wash out debri or even use an air hose.
I installed a Teleflex temperature sensor on the head of my DT140 with a console mounted Teleflex temp gage to provide a temperature reading so I could see if and when I had a abmormal temperature problem over an above just having the Suzuki warning monitor/gage. I was going to install a pressure gage but I was concerned of breaking off the small plug on the head for the sensor.
Phil...

 

[deejaycee_2000]

Re: DT115 Hot Cooling Water

how did you seal around the waterpump housing? If you do it wrong you can also cause a bit of problems ....

 

[Marion Moore]

Re: DT115 Hot Cooling Water

hopalong,
the passages are clear as far as I can tell. Right now the heads are OFF of the engine as well as the pass through gromits. What a strange system, maybe other outboards do it too, anyway. When I get my gaskets I will put the whole thing back together and try the flush idea with a hose from the thermostat location down. Looking with a flashlight all of the passages are clear and clean. The thermostat is new but it have not checked it. It could be bad out of the box. An external thermostat is a good idea.

deejaycee_2000,
I sealed the outside edges of the water pump housing (metal, not the plastic one) with RTV. My guess is the worst thing that might happen is a piece could float around inside the exhaust passages which should not hurt anything. It probably will not help anything but I thought I would try.

Marion

 

[Marion Moore]

Re: DT115 Hot Cooling Water

Update
I tested the old and new thermostas in heated water with a thermometer. They both worked proberly. I also tested the old and new engine block temp sensors. Both did not exactly match the ohm readings the manual suggested when the temp got up around 130 F. but they both ageed with each other. Don't know what that exactly means.

I finally received my parts and put everything back together. Torked the head bolts according to the service manual. I hooked up the water hose and fired it up. The water still feels hot. Water was leaking around the mock flow sensor (my 115 is the EFI model) so I know water was getting to the top of the head.

I'm going fishing this weekend so I will keep a close eye on it. The real test will be how it reacts when the lower unit is fully submerged.

Hopalong,

What does your external Teleflex temperature sensor typically read? The service manual says the high temperature alarm should go off at around 127 F. I have not measured my tell tail water temp but I would expect to get a burn around 130 F. It is fairly close to that because it is uncomfortable but bearable.

 

[hopalong]

Re: DT115 Hot Cooling Water

With the muffs on temp reads about 125 BUT I've had the temp upwards of 130-135 and the alarm never sounded. The alarm does sound off at the correct hi temp limit setting...not sure what the setting is though. Did not have temp gage installed then. I believe I was told the alarm limit setting was above 140 degrees

 

[Marion Moore]

Re: DT115 Hot Cooling Water

Update
I ran the boat this weekend. Every time I felt the tell tail water it was warm, not hot. I guess I did all of that work for nothing. In the past I have stoped at a fresh water river to flush the engine after fishing in salt water so I guess I should continue to do that. My final assessment is the hose supplied water must not provide enough flow to cool the enging properly.

Marion

 

[hopalong]

Re: DT115 Hot Cooling Water

To be on the safe side I would suggest to install a temp gage or pressure gage so you can be sure what temp it is running now and in the future. Especially if your alarm fails you will have something to see if it is running hot and know to shut it down.