130 hp yamaha high speed overheating

[RedRustler]

I have a friend with this motor and he recently replaced his thermostats,impeller etc.<br /> <br />last weekend we took the boat out and after running for between 5 to 10 minutes at 5500 rpm <br />the overheat buzzer would start up. <br /><br />running between 3500 to 4500 the problem would not happen. So i asked a few questions during the week and came up with cleaning out the high pressure releaf gromet.<br /><br />then my friend tells me that when he flushed his motor that he seen water coming from underneath the coweling. After removing the coweling he noticed that water was coming from or around near where the upper lower unit bolts to the powerhead.<br /><br />I am wondering if there is some sort of pressure release or blowby valve that releases when the high pressure mech. isnt working correctly?

 

[rodbolt]

Re: 130 hp yamaha high speed overheating

hello<br /> while its very rare to have a problem at high speeds with the pressure control valve it can happen. most problems are with low water pressure due to a stuck valve. does not take long to clean it.its just a plastic spring loaded valve the regulates water pressure not much to it but it does require maint. most overheat problems above 5000 rpms are due to scale in the block and water jakets. if all else tests ok its time to pull the head water covers and the heads for a cleaning and inspection.

 

[Ray Neudecker]

Re: 130 hp yamaha high speed overheating

The leaking around the power head indicates the base gasket may be leaking.

 

[rodbolt]

Re: 130 hp yamaha high speed overheating

ray<br /> yep it may have other problems. but most times a base leak wont cause overheat. it will cause corrosion problems and possible damage by water ingestion though. I have a 1989 225 excel that purrs like a kitten. it has a pinkie finger sized hole in the water cross over passage under the head between the V. nothing will fix it short of a block replacement sothe man bought a motor. one day I will find a clean block for it and go play . in the meantime its in the project boneyard .

 

[RedRustler]

Re: 130 hp yamaha high speed overheating

I assume changing the base gasket calls for removing the powerhead?

 

[rodbolt]

Re: 130 hp yamaha high speed overheating

redrustler<br /> if that motor has much saltwater use the bolts are all but impossible to remove. I usually end up cutting the powerhead adapter. how old is this 130 and is it a saltwater use motor. by saltwater I mean if you can catch crabs its salt water.

 

[RedRustler]

Re: 130 hp yamaha high speed overheating

LOL, yes it is a salt water motor. i am not sure of the year of the motor i beleave it is no older than a 97 model and was always well taken care of.