'07 R21-EC engine temperature climbs on increase in RPM

[r67boxer]

While out on a cruise the other day my engine temperature registered, as it always does, just shy of 175 degrees. I was running along at about 2200 RPM. When I increased the engine speed to 3100 RPM I noticed a slow creep up to about 177 degrees. Is this normal or is it time to change the sea water impeller?

Kevin

 

[Rode Trip]

It's not unusual and it's nothing to worry about as long as it doesn't keep going up. Good idea to open it up to wide open throttle every now and make sure the temp holds steady. Raw water impeller is normally a 2 year replacement item.

 

[r67boxer]

It's not unusual and it's nothing to worry about as long as it doesn't keep going up. Good idea to open it up to wide open throttle every now and make sure the temp holds steady. Raw water impeller is normally a 2 year replacement item.

Thanks. I will keep an eye on it. The R21 is new to me so no history to speak of but there was a spare impeller and O-ring in one of the cupboards.

Kevin

 

[4umfreak]

If you don't have details on when that impeller was last changed, then it should be replaced, or at least inspected immediately.
I'd say that the same goes for fluids, filters etc on a new to you boat.

Just my $0.02

 

[Newf]

Just an opinion but I would think that a 2 or 3 degree temperature rise with an increase of 900rpms is quite insignificant.

 

[r67boxer]

If you don't have details on when that impeller was last changed, then it should be replaced, or at least inspected immediately.
I'd say that the same goes for fluids, filters etc on a new to you boat.

Just my $0.02

As I said above I will keep and eye on the temperature but will also pull the cover off the pump to check the impeller. I have gone through the entire boat WRT fluids etc. and have changed the water separator filter, as well as fuel filter. The engine oil had just been changed and transmission oil is up and clean.

Thanks to all for your input.

Kevin

 

[r67boxer]

As I said above I will keep and eye on the temperature but will also pull the cover off the pump to check the impeller. I have gone through the entire boat WRT fluids etc. and have changed the water separator filter, as well as fuel filter. The engine oil had just been changed and transmission oil is up and clean.

Thanks to all for your input.

Kevin

As an update, I changed the impeller and much to my dismay found that three of the blades were missing. One was laying in the bottom of the pump, which left two. I then took off the hose leading from the pump to the heat exchanger. Another one fell out of the hose (which I replaced with a new one), that left one! I carefully stuck the pointy end of a chop stick into the chamber leading to the heat exchanger and the third one fell out. When I started the engine I noticed a significant increase in flow coming from the exhaust port. Thanks to all for their suggestions.

Kevin

 

[PanaSeaAh]

As an update, I changed the impeller and much to my dismay found that three of the blades were missing. One was laying in the bottom of the pump, which left two. I then took off the hose leading from the pump to the heat exchanger. Another one fell out of the hose (which I replaced with a new one), that left one! I carefully stuck the pointy end of a chop stick into the chamber leading to the heat exchanger and the third one fell out. When I started the engine I noticed a significant increase in flow coming from the exhaust port. Thanks to all for their suggestions.

Kevin

You were lucky the impeller blades broke instead of shredding. Picking a couple dozen small pieces out that are too small to go through the exchanger is not easy.
One other thought; if the impeller was run dry for more than 30 to 60 seconds, it could overheat and fail regardless of age. Sounds like you recently acquired the boat, so you could have been in either situation. You are correct that checking the exhaust flow is a good way to check for adequate pump flow. I do that every time I start the engine.