mERCURY 50 HP 4 STROKE OVERHEATING

[David R Lewis]

My 50 hp 4 stroke mercury overheats and the alarm goes off after several minutes of warming up. I have replaced the water pump and it works fine on a garden hose, but will not pump by itself in the water except for about 3-5 minutes before it quits.<br />I removed the thermostat and put it in hot water and it opens. What next to check?

 

[Kanadakid]

Re: mERCURY 50 HP 4 STROKE OVERHEATING

David,<br /><br />Since this is really a Yamaha I would post this in the Yamaha forum. There are a couple of Yamaha techs (Rodbolt and others) over there that I'm sure will help you.<br /><br />Just say Yamaha F50 overheat. <br /><br />From a novice, I know there are sensors in there and sounds like one of those is sending bad info to the ECM.<br /><br />Kid

 

[Bailey4427]

Re: mERCURY 50 HP 4 STROKE OVERHEATING

Hello Kanadakid,<br /><br />Are the 60HP Mercs. also made by Yamaha?<br /><br />Just curious.......<br /><br />Thanks,<br />Bailey

 

[WillyBWright]

Re: mERCURY 50 HP 4 STROKE OVERHEATING

They include Yamaha internal components, but the blocks and everything below is made by Merc.<br /><br />I'd guess you sucked-up some sand and clogged the powerhead. You might be able to back-flush most of it out. Remove the thermostat and put a garden hose to the opening and flush (motor not running, straight up and down). Run the motor as soon as possible afterward.