Crusader 270 motor getting hot

[jif102]

I have a 1988 Silverton 30X with Dual crusader 270 inboard motors. When I launched the boat this year after winter storage my starboard engine wants to heat up. The only thing that changed from last year is a new thermostat. I turn the engine on and the temperature will gradually rise. I shut the engine down before it hits 200. The engine is raw water cooled.

I have been trying to trouble shoot this the past few days. I have replaced the impeller on the raw water pump and back flushed the oil cooler to remove any debris. Even after this the temperature still rises. What I notice is that all of the hoses are cool to the touch expect the circulation pump hose that goes to the thermostat housing. I removed the thermostat and ran the motor shortly with no thermostat. Of course the temperature dropped quickly.

My next step is to get a new thermostat and try that. I am also going to jump the temperature transmitter to the other engines temperature gauge to make sure that the gauge is working.

Are there any other recommendations for me to look at before I tear into the circulation pump?

 

[alldodge]

Can you see water coming out the exhaust, and how does it compare with the water coming from the other motor?

 

[Scott Danforth]

you should have a raw water pump as well in addition to the circulation pump. how is the raw water impellers?

generally rising temperatures is a sign of low or no water flow. either no water coming in (bad pump, pickup, sea-****), or no water going thru (blockage, etc), or no water coming out the motor (blocked exhaust passages).

 

[jif102]

I put a brand new impeller in the raw water pump last night. It did not change anything.

 

[alldodge]

Can you see water coming out the exhaust, and how does it compare with the water coming from the other motor?

Can you see your exhaust?

 

[jif102]

I will be able to go to the boat after work today. I will take a look at the exhaust. It is just above the waterline but I should be able to see it from the dock.

 

[jif102]

Updated. I bought a new 160 degree thermostat. I put that in and started both motors to compare the amount of water coming out of the exhaust. Both exhaust water flow looks about the same. With the new thermostat the engine temperature did settle down. I let the motors idle for about 30 minutes. The starboard motor temp never went about 180 degree. The port engine stayed at 160. All of the exhaust hoses / manifolds were cool enough for me to place my hands on. The only hose that was warm to the touch was the circulation pump discharge to the thermostat hose. Both engines seems to be similar temperatures to the touch.

I do know that last year there was a 20 degree difference between the motors. I though there were 2 different temp thermostats. I am still seeing about the same difference between the motors.

I now need to figure out why the temperature difference is occurring between the motors.

 

[alldodge]

I now need to figure out why the temperature difference is occurring between the motors.

It could just be the gauge. There is a single wire (Tan) on the back of each gauge which goes to the motor sensor. Swap the two wires to the other gauge and see if it moves or stays with the gauge. If it stays, then its either the sensor or the motor is hotter. If it moves then its the gauge

 

[Scott Danforth]

Dash gauges are merely a suggestion of what is going on. The senders are up to 10% inaccurate, the gauges are up to 10% inaccurate