Re: 2001 40hp merc jet outboard
Like he said, first step is to try to blow out or ream out the telltale. You might consider replacing the water pump impeller if that hasn't been done in a while, or if you're not sure when it was done.<br /><br />I would also suggest you assess the flow when the engine is in the water, not on the hose. In my experience - which may or may not apply to you - running my outboard jet on the hose never results in either tell tale flow or water pressure (I have a gauge) that is anywhere near what it is in the water. I have a new impeller and get strong water pressure idling and running in the water, but very low on the hose. I know it's not a water pump issue, but I think it's related to the jet unit. The flush port on the jet unit supplies the water pump, but also supplies the propulsion impeller (which as you know spins whenever the engine's running, in neutral or not). When you're running it on the hose, you'll see water coming out the bottom grate and pump outlet (as well as the tell tale). This leads me to think that's the reason I'm not getting high water pressure or tell tale stream.<br /><br />By the way, I really recommend a water pressure gauge. For my engine it was very easy to install. With my jet, my tell tale is/was always getting plugged from very minor debris. The pressure gauge allows me not to worry about it- I can just glance at the gauge on the dash instead of lookign back at the tell tale.
