I'm am lost with this engine, as I feel like I am chasing so many weird problems. This is a new problem this season though. First time out, got a high temp alarm and my son (who was using boat) realized there was no water coming out of tell tale when going fast (he was on plane). He let the engine cool and he thought the tell tale was just clogged, so he twisted some weedwacker line we keep in the boat up it, and water flow returned while he was sitting there. Thinking maybe I had a blockage or a spun impeller, I took the boat home, changed the impeller (the one in there was fine though), made sure the keyway was installed, and checked all water passages and pickups for clogs. As far as I could tell, nothing was blocked.
A few observations. With the thermostat out (but engine running with tstat cover on), simulating an open tstat, water flow in neutral at idle was weak. With tstat installed water flow was strong. Maybe normal, but wanted to mention it (seems odd to me). The tstat cavity looked gunked up, so I ran a vinegar wash through it for a while and got some junk out, but not much. I did get some flow from the tell tale after this with the tstat removed and cover on. At this point I put a new thermostat in and brought it back to my slip for testing.
I guess I never paid attention to tell tale water temp before too, but water temp on the tell tale output is 95 degrees, I assume this is correct as the water circulates through the block so it will be warm when the engine is.
Running at the dock in neutral the tell tale is good and strong. Reving the motor in neutral it continues to be strong even in the upper RPMs. But running the boat up on plane, the tell tale stream slows to a trickle around 4700 rpm. If you keep running it I assume it would throw an overheat warning. If you drop down the rpms down and slow the boat the water flow returns in just a few seconds.
What the heck is going on? Is it cavitating and not getting water into the pickups? All of a sudden? Nothing about the motor configuration changed, nor did anything change on the bottom of the boat. I just don't get it.
So in short, 1) is 95 degree water from the tell tale on this motor considered normal (it shouldn't be cold), and 2) why the heck am I apparently losing water flow from the tell tale when running around 4700rpm? As soon as you drop rpms, the water flow returns. Could a blockage cause this, but only when running fast?
(I won't mention the stupid occasional stalling it does when reducing to idle or neutral. Really fun docking in a strong river current).
Thanks!
A few observations. With the thermostat out (but engine running with tstat cover on), simulating an open tstat, water flow in neutral at idle was weak. With tstat installed water flow was strong. Maybe normal, but wanted to mention it (seems odd to me). The tstat cavity looked gunked up, so I ran a vinegar wash through it for a while and got some junk out, but not much. I did get some flow from the tell tale after this with the tstat removed and cover on. At this point I put a new thermostat in and brought it back to my slip for testing.
I guess I never paid attention to tell tale water temp before too, but water temp on the tell tale output is 95 degrees, I assume this is correct as the water circulates through the block so it will be warm when the engine is.
Running at the dock in neutral the tell tale is good and strong. Reving the motor in neutral it continues to be strong even in the upper RPMs. But running the boat up on plane, the tell tale stream slows to a trickle around 4700 rpm. If you keep running it I assume it would throw an overheat warning. If you drop down the rpms down and slow the boat the water flow returns in just a few seconds.
What the heck is going on? Is it cavitating and not getting water into the pickups? All of a sudden? Nothing about the motor configuration changed, nor did anything change on the bottom of the boat. I just don't get it.
So in short, 1) is 95 degree water from the tell tale on this motor considered normal (it shouldn't be cold), and 2) why the heck am I apparently losing water flow from the tell tale when running around 4700rpm? As soon as you drop rpms, the water flow returns. Could a blockage cause this, but only when running fast?
(I won't mention the stupid occasional stalling it does when reducing to idle or neutral. Really fun docking in a strong river current).
Thanks!