Alarm At High Revs

[kykeka]

I have a 1989 225 Yamaha Excel V6. It runs great up to 3900 RPM. At higher RPM (4000 -4500),it will run for about 5-10 minutes,then a steady alarm goes off and the motor starts shutting down. After 2-3 minutes turned off, the alarm goes away and all is normal until its pushed to a higer RPM over 4000.I replaced the thermostats .I can run over 30 miles at 3900 RPM no problems.All gauges are normal at time of alarms. My oil pump went bad, had oil tank removed, sensor disconnected on sub tank on engine,I mix 50 to 1 on oil, runs better than ever. Just want high RPM alarm to go away. Thanks

 

[Steamboat]

Re: Alarm At High Revs

Have you checked the cooling system for proper function?If not, sounds like you have a partial obstruction of the cooling system and the high temp alarm is making the engine shutdown or operate at rduced rpm to save the engine. You can try back fluching the engine by pulling the lower unit, take out the thermostats and putting the water hose in the thermostat openings and catch the outflow from the water tube in the mod section to see what kind of debris you get.

 

[rodbolt]

Re: Alarm At High Revs

post the model number<br /> I dont think they made the excel in 98<br /> but there were 225's made in two block designs. both with different cooling systems.

 

[kykeka]

Re: Alarm At High Revs

I messed up it's a 1989 225 Yamaha Excel, I have a 1990 Pro Line W/A Cuddy. Sorry Mark

 

[ianyoung77]

Re: Alarm At High Revs

kykeka,<br /><br />When did you last change the impellors? I have a much smaller motor but it does the same when the impellor needs changing<br /><br />Ian

 

[kykeka]

Re: Alarm At High Revs

I changed it about a year ago. Mark

 

[ianyoung77]

Re: Alarm At High Revs

kykeka,<br /><br />I had mine go after only one year. After that I decided to try using the MACS flush additive and have gone 2+ years without the problem occuring.<br /><br />If you do it yourself it is fairly cheap and easy to change the impellor. Once this is done you have eliminated this as a possible source of the problem.<br /><br />How long do you flush you motor?<br /><br />Ian

 

[kykeka]

Re: Alarm At High Revs

I just fresh water flush from hose for about 3-5 min. Never tried MACS flush additive or any other additive. Mark

 

[ianyoung77]

Re: Alarm At High Revs

Mark,<br /><br />A Suzuki tech told me to always flush for 10 minutes to ensure the thermostat opens fully. I have been doing this for the last couple of seasons as well as using MACS occasionally and haven't changed my impellor since. Before I did this I only got one season from the impellor.<br /><br />It certainly can't hurt to try.<br /><br />Ian

 

[rodbolt]

Re: Alarm At High Revs

make sure the pump assy is in good shape. if its good then you may have a scaling problem or head gasket sealing issue. they can leak combustion gas into the cooling system and the symptoms start showing up above 4K. eliminate the common parts of the cooling system then pull the heads.

 

[kykeka]

Re: Alarm At High Revs

Thanks Mark

 

[dougs2452]

Re: Alarm At High Revs

kykeka, <br />I think your boat is toast you should give it to your friend dougs2452 and drive him crazy trying to fix it