Re: Can't fnd thermostadt on this 40 HP Merc
Yikes, Really? That was my next step in my quest to find out why my engine triggers overheat alarm when I get past 4000 rpms. Was also going to change out poppet vave. Does it not have that either? The other morning I was able to cruise up past 5000 rpms fine for about 2 minutes (before engine warmed up). Once its warm, I cannot get past 4000 rpms without alarm going off. Just replace water pump last week so its not that. Only other thought would be position of prop in the water and not gettng enough water when the boat gets on plane. The prop is about 6 to 8 inches below the bottom of pontoon so I wouldn't think its that. Will have someone watch the engine as I get up to plane next time i'm out.
Any ideas what else could be replaced to diagosis this issue?
