I posted back in July about an overheating problem on my port machine. I have replaced the Thermostats, Water Pump Impeller, Cleaned the PR Valve and tested the Thermosenders and I my alarm still trips from time to time at various rpms. Any ideas??
250 Yamaha '2000 2 Stroke Overheating
- Thread starter vangrady
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plymouthgrady
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If you are lucky, the temp sensor is bad.
If you are unlucky, you could have anything from a stuck popet valve to an exhaust leak into the coolant.
If you are unlucky, you could have anything from a stuck popet valve to an exhaust leak into the coolant.
plymouthgrady
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If you only cleaned the p/r valve, replace it. The rubber fatigues loosing its elasticity.
Also, if you can borrow a temp gun, aim it at the thermostats and see what the temp is on both sides when it buzzes and what the temp of the block is.
You mentioned you replaced the water pump impeller, did you replace the pump?
Also, if you can borrow a temp gun, aim it at the thermostats and see what the temp is on both sides when it buzzes and what the temp of the block is.
You mentioned you replaced the water pump impeller, did you replace the pump?
Went through the same thing with a 2001, 150 and ended up pulling the water jacket from the cylinder head on the starboard side. Jacket was semi-clogged with junk. Just enough to allow running below 4000 or so but would trigger the alarm above 4000. I used my IR gun to troubleshoot which bank was overheating. Ended up pulling the heads on both banks and cleaning out water passages, installed new gaskets and problem solved. If you have to do this and have a dealer close by, you can take the heads and water jackets to them for a "dip" which is much neater and more effective than hand cleaning them. Not sure what they do as I did mine by hand but was told later this is the easy and most effective way to clean them. If you do them, be sure to use a torque wrench to tighten head bolts and then re-torque them after you run the engine. Good luck.