mercury 50hp overheating

[wesg]

boat is 5 yrs old but only been run for about 4 hrs, 3 yrsl ago, got fresh gas, oil, & plenty of water but temp alarm keeps going off after running about 3-5 min. chkd temp last time and motor got up to 222* F., tstat reset at 155* F. running smooth until alarm starts going off and then revs up and runs rough. what could be wrong?

 

[Dunaruna]

Re: mercury 50hp overheating

[colour=blue]Hi wesg, welcome to iboats!

Is water flowing strongly from the telltale?

 

[wesg]

Re: mercury 50hp overheating

yeah, very good stream, and it is not hot only warm, maybe 1oo*F

 

[wesg]

Re: mercury 50hp overheating

this is with the muffs on. does it need to be in the water?

 

[Dunaruna]

Re: mercury 50hp overheating

[colour=blue]Yes. When it's on muffs the water pressure is supplied by your garden tap, not the water pump. To test the pump, use a large bucket (rubbish bin!?) full of water and start her up.

 

[wesg]

Re: mercury 50hp overheating

checked with motor in big trash bin. still overheating. pulled tstat and no water showing there. telltale stream still not barely warm to touch. at a complete loss here.

 

[Don S]

Re: mercury 50hp overheating

What's the SN of your engine? 2 or 4 stroke?

 

[wesg]

Re: mercury 50hp overheating

ot729111 2 stroke 3 cyl.