I have a 2003 Yamaha 200hp 2 stroke. The overheat alarm sounds when flushing with ear muffs and when the engine runs in idle or a little above at trolling speed for extended period. No problem at cruse speed. The water stream appears to be normal but perhaps weak at idle? Is this likely the water pump or thermostat?
I plan to replace the water pump but was wondering how often the thermostat on these engines goes bad?
Out O’ Line
It may just be the impeller. Impellers they say are supposed to get replaced every season. The impeller may just not be pulling enough water. If you do dry starts without being in the water or being hooked up to a hose they can get ruined pretty quickly. It’d be alot cheaper fix.
Thanks for the reply Joke. I was planning to get the pump rebuild kit but probably should take it apart first and see what parts are need. I have replaced OMC impellers before and this looks to be about the same from the manual illustrations.
Out O’ Line
Just buy the complete kit for your engine. Replace everything that the kit contents cover.
If the water pump kit doesn’t improve the situation, the problem could be a poppet valve stuck open or the water tube that directs water from the pump up the engine has a leak.
Iain Pelto
Edgewater 185CC “Jumpin’ Bean II”
Yamaha W/P kits don’t come with a new housing like OMC, so you need to inspect for melting or you will have another overheat problem or just replace the housing too.
Mine did the exact same thing. Housing started to melt and blocked off part of the water flow.
24 proline twin 150 mercs
Where’s the best place to get these parts?
Happy boatin’ y’all!!
John at Hankle, you could probably find someplace cheaper, but you won’t find a better Yamaha parts man
How frequently is it recommended to replace the thermostats. ?Only when they go bad or is it a good idea to replace every # years as routine maintenance. If the T-stats go bad, wouldn’t you get the overheat at all speeds or would it be a different symptom?
Ben Miller
quote:Thermostats wouldn't set the alarm off till the motor got going and up to speed @ idle the thermostats are closed trying to get the motor to temp. We took the therms out of a 70 Johnson we used to have and ran it for years without them with no problems. Motor had 3000hrs before we shattered a piston, then rebuilt it and ran it another 1500 before selling it.
Originally posted by Miller TimeHow frequently is it recommended to replace the thermostats. ?Only when they go bad or is it a good idea to replace every # years as routine maintenance. If the T-stats go bad, wouldn’t you get the overheat at all speeds or would it be a different symptom?
Ben Miller
21 Contender
After re-building the water pump with all parts except the housing (which showed no signs of melting or cracks) I am still getting the alarm when flushing with muffs. I have not had a chance to do extended slow troll at idle but I expect I will get the alarm again when I do.
What should I check next to remedy this problem?
I have no problems during any other operating conditions!
Out O’ Line