Overheating at mid throttle

S

speedmerchant

Seaman Apprentice
Joined
May 25, 2009
Messages
34
I have a 1999 Volvo Penta 5.7 GS in my sport cuddy. Noticed on the weekend that it runs close to 250 degrees when run at mid throttle for about 5-10minutes with the boat just on plane or a bit above. In the 2500-3000rpm range. If I throttle it back, even slightly, the temp returns to normal or if I pick up the pace even to WOT it is also fine. I played with the trim and it helped only slightly, just enough to say that the needle moved lower, barely. Is this something normal? Kinda new to boating with inboards. I have replaced the thermostat and impeller already this season. Any ideas?
 
J

joeyr

Seaman Apprentice
Joined
Aug 14, 2008
Messages
32
Re: Overheating at mid throttle

I had the same problem last year with a MR series merc outdrive. Turns out I melted a small pipe that connected the empeller in the lower outdrive to the upper outdrive. So the result was water would only make it to the engine when certain criteria were met. In my case, when it started overheating, I would have to go in reverse for a while. Figured it out when I took it appart last winter.
 
S

speedmerchant

Seaman Apprentice
Joined
May 25, 2009
Messages
34
Re: Overheating at mid throttle

hmmm thanks Joey. Mine is a Volvo SX drive and I don't believe they have impellers in the drive units. That being said does anyone think it could it be a problem with the water tube in the drive? I just had it replaced though.
 
You must log in or register to reply here.
Top