PDQ OWNERS FORUM

I have my starboard engine temperature running at 195 degrees F while the port engine is 175 degrees F. Does anyone know what is the proper temperature for the 100 horsepower engines at WO ? Based on a visual of the exhaust both have about the same water flow. Also noticed that the oil pressure on the starboard engine runs a little higher than the port engine. Does someone know what is normal oil pressure at WOT?

Dennis and Cindy Strecker
Hull 95

i can't answer any of your question (we have 75 hp) but for 18 years our stb engine has run hotter than the port. i can't say why. thought a lot about it but nothing concrete.

Dennis,

We have the 110hp Yanmars in His Idea (2000 hours). I believe they are quite similar to the 100hp engines, so our experience with them may be of interest.

When operating properly both engines run at 175 degrees F, including up to WOT, which I understand is the correct temperature. Last season we developed an overheating issue on one of the engines at 2600 RPM (14 knots, our fast cruise). After considerable time trying to diagnose the cause our mechanics determined that the surrounding cover for the heat exchanger had loosened and rotated, restricting the water flow at exit because the openings had become misaligned. Apparently the securing mechanism is a set of simple 'dimples' that hold the cover in position, so the fix was to rotate the cover back into position and 're-dimple' it. We have had no issues since.

I don't know if you're experiencing the same issue, but it may be worth an inspection of these parts to see if that is so. Our mechanics had never seen anything like it before, but that doesn't mean it couldn't happen elsewhere.

Regarding oil pressures, we do see a slight variation displayed on our two gauges. They register about 50 when the engines are cold, 35 or so at 2600 rpm, and just above 20 when idling. This pattern has been evident since we bought the boat. I doubt your cooling issues and oil pressures are related.

Hope this helps.

Cheers,

John

Our Yanmar temp and RPM gauges do not report accurate temps/RPMs. It may be due to the wiring runs and voltage drops. One of our RPM gauges is actually 200-300 rpm off!

I installed EMU-1 engine monitors on each engine and they are spot on- the engine thermostats open up at exactly 169F and the engines run at around 175F.

I will have to check and see what kind of oil pressure we get, but again, the Yanmar/VDO gauges are probably not very accurate.

Hope that helps.

Thx,
Doug
MV 34 #102

I ran the engines at the dock up to 1400 rpm with the props engaged. The gauge readings after a while settled to approx. 165 on the starboard engine and about 180 on the port engine. I then checked the coolant water pumps near the temperature sending units with an infrared gun. The starboard engine read 164 and the port engine 162. So it appears that the port engine has either a faulty gauge, sending unit or wiring. I plan on checking the readings later this week when I take the boat out on the lake where I can running it to cruising speed. Meanwhile I will be cleaning wiring connections.

Thank all for your experiences.

Dennis & Cindy
Hull 95

We had the port engine running around 190 at one point. I took the heat exchanger out and cleaned it. That fixed the problem. It is not a difficult job.

Alan