Overheat Problem

[mpk59]

Hi,i have a 99 2stroke 125hp mercury ob that starts to sound off after maybe 10 mins. of no wake zone rpm's.the engine sounds fine.If i cruise or run at full throttle everything seems fine,engine sounds great,no overheat buzzer,water is peeing out with nice stream. Water is hot but can hold my finger under it for awhile.Was getting short bursts of this problem a month ago then had no problems the last 2x's out.Any suggestions would be great. Thanks Marty

 

[Dave1027]

Re: Overheat Problem

What does the temperature read during no wake? Mine goes up to about 145 degrees.

 

[jhcreech]

Re: Overheat Problem

sounds like the t-stat is working as designed, can u gauge the actual temp...

 

[mpk59]

Re: Overheat Problem

Hey guys,i don"t have a temp. gauge on the boat.This just happened yesterday.thanks!

 

[Dave1027]

Re: Overheat Problem

Hey guys,i don"t have a temp. gauge on the boat.This just happened yesterday.thanks!

If that's the case you better start by replacing the impeller and maybe the thermostat.

 

[mpk59]

Re: Overheat Problem

Thanks i"ll give that a try.

 

[hkeiner]

Re: Overheat Problem

Installing a water pressure gauge is a good way to monitor and troubleshoot the cooling system if something seems wrong. One can be installed on a temporary basis to troubleshoot an existing problem or installed permanently for ongoing monitorinig. The below linked guides help explain this further.

http://www.diy-boat.com/index.php?option=com_content&task=view&id=151&Itemid=49

http://forums.iboats.com/attachment.php?attachmentid=26806&d=1240515681

http://forums.iboats.com/attachment.php?attachmentid=39965&d=1256599637