Are Recmar thermostats bad?

[Mastiff]

This is funky. I had my old thermostat on my DF140 2011 lock in open, so the engine ran at about 40 C according to my Garmin 720S with Suzuki Engine interface (water around 15 degrees C, this is normal in Norway in late August!). I replaced it with a Recmar from a reputable dealer, and tested it by the dock in idle speed. It went slow and steady up to 61 degrees, which should be about right for a 60 C thermostat. But when I took the boat out to do a bit of fishing I noticed that after a while on just above 2000 RPM's it was up to 75 C!

Suzuki temp.jfif

Thinking the thermostat was bad and opened only half way I called the shop on the phone and got a replacement for free, without any problems. Only to see the exact same thing! The model is REC67F-12411-01, which is supposedly for Yamaha as well as my DF140. But still I get this strange result. So is there a known problem with Recmar's thermostats in this respect?

[seaox230c]

If you have the old one drop it in a pot of water with a thermometer and slowly heat it up..see what happens

[Mastiff]

Thanks! But the really old one was wide open without heat, stuck open. The one I replaced last week I threw away because I thought it was faulty, until a few days later, when I tested the new one at speed and found the same problem. I wonder if it can be the water pressure valve or a worn impeller, but from what I read that should have more effect on idle, when the water comes slowly.

[Murray]

If your water pump hasn’t been changed in a while I’d suggest you change it out. I said water pump not impeller, Suzuki sells a kit which has new housing, new base plate, new impeller and new gaskets. Suzuki also sells a “Maintenance Kit”, that kit has new water pump assembly, plugs, oil and fuel filter, anodes, o rings for the drain plugs for around $150.

[Mastiff]

Murray Thanks, It has. I got a fully overhauled lower unit two years ago. And I now tested with my neighbour's thermostat. He has a DF140 that's a few years older than mine, and it went quite quickly up to 73 C, then fell down to 69 and then stayed between 69 and 71. So I'm pretty sure he has a 71 degrees thermostat, and that it worked as it should on my outboard. I have ordered a new 60 degrees thermostat from another brand, I hope that will fix it.