2008 df140 temperature issues

[Fish4jesus]

i have twin 140df’s I bought boat used and motors run great. I performed all maintenance when I bought the boat on down to poppit valves. I run salt away and do did the previous owner.
My port motor has a great stream, I noticed the temp reaching 174/178 while under way. This is at 4100 on up. Idle it sits at around 160 ish. I’m at a loss on why and I’ve used 3 different thermostats (60) all new. Is that temp ok for these motors or should I be down in the 150/160? Starboard motor runs 165/172
Any info or help will be great, no alarms have went off.

[Ole Joe]

I have twin 2003 DF 140s with 2,250 hrs on them.

At idle, external heat gun shots read: 126 & 127 at the thermostats, 149 & 147 at the top cyls, 140 & 138 at the temp sensors, and 108 & 105 at the bottom cyls.
At 1,500 RPMs the thermostats increase to 144 & 147.
All figures shown are Stb & Port respectively.
I have no data above 1,500 RPM, but hope these give you a reference benchmark.

My 2003 manual shows the "Hot" threshold light is 121 C (250 F) for the cyl temp and 114C (240 F) for the exhaust temp.

BTW, these motors are used on the mid Atlantic coast and the Chesapeake Bay. I use Salt Away at the end of the season each year.

Hope this helps.

[Ole Joe]

Bump to post

[Solarman]

In the parts listing for some older motors (2008?) It lists a sub- water cooling system as part of the make up water going into the water pump cavity. I'm not sure if your motor has this sub-water pick up? But my older 2 stroke motors had this. Also, the parts list doesn't show it in detail? But on my motors there was a rubber grommet protected by a stainless shield going into the water pump cavity below the pump. Apparently the previous owner/mech that worked on my motors installed the heat-shield incorrectly, and both of my motors had burnt rubber grommets. So on my motors the exhaust gases would interfere with my water pump picking up water as exhaust pressures would push the water out of the cavity as the rpms increased.

I'm not saying this is your problem, but it sounds similar to mine. If you have the sub water cooling tube that runs from just above the prop, through the exhaust pas-sage to the water pump cavity, it is worth inspecting.

You mentioned replacing the water pressure valves, and other components, those are the most common problems for water systems.

Good luck, post back on what you find out.