Another Merc?

[slammer]

I was talking to a buddy about my motor not shooting out much water when running and he said it may need a new poppet valve? Anyone know what it is and what it does? How hard to replace? Its a 99 150 EFI Merc.

[Valv]

I would tell your friend you already replaced the muffler bearings and you don't need it anymore .

Joking aside, if you don't have much water stream you might want to have water pump replaced, it's not a very expensive job if done on a routine basis, and if you are mechanically inclined you can do it yourself with no problem, this is must do every 2 or 3 years before season starts (IMO).

Otherwise take it to a shop, I would expect price to be between % 150 to $ 250 including labor, parts only should be around $ 50.

Don't procrastinate on this, or you might have much more expensive repairs later on in the season, besides loosing the fishing time.

The cooling of an outboard is a very simple system, regardless of years they didn't change them much. Basically a rubber impeller installed on the driveshaft inside the lower unit shoots water up into the block, then water exits the motor by going back down the lower unit and out through the propeller. A thermostat keeps water a little longer inside block to keep temperature constant, the small tell tale stream you see on the side of the motor is used only to give a visual of the water circulating the motor, since there is no or very little gauges installed on boats.

That's it.

[CAMAN]

LOL @ poppet valve!!

Great explanation Valv.

[slammer]

Well after a little investigating I now know what a poppet valve is but still dont know what it does. Found a video on u tube of a guy changing it but I dont think he ever explains what it does. As far as the impeller goes, I have changed that 3 times last time being a year ago. Also pulled the thermostats out and replaced them. Checked as many hoses as I could find and none seemed to be plugged. I do as much maintenance as I can on my cars and motorcycles but boat motors are a different breed. So, anyone know wat the old poppet valve is for?

[boatfixer]

It acts as a relief valve when the thermostat is closed.

[BoxMN]

also, 150efi's don't really "pee" in a hard stream at idle. So it might appear weak, and it sdoesn't start right away, all the time. So it won't look the same as many other motors even though the impeller might be perfect. But as was said, every few years change it whether needed or not, easy cheap routine thing to do. Great motor