Warm it up if you want it to last. I always idled a little bit and never went hammer down until my temp gauge showed full temp. That was usually a mile or 2 at around 3500.

thank you for the advice.

Merc smart guage

This is how it’s done.

If you dont get any of these motors to a min of 100 degrees before you mash it you stand the possibility of a ring sticking to the cylinder wall which then pulls the top off the piston....

It happened to me on Falcon last year. I had debris in a thermostat so it was stuck open and that side of my engine NEVER would get up to temp. The temp sensor of course was on the other head.. The pro xs 2 stroke at least has two stats one for each side.

A few minutes and let
Her rip

Yea, mines a 150 Yami 4 stroke, with no temp sensor. I start it as soon as I drop it off the lift and have to idle out of the marina. So maybe idle for 5 minutes. Hoping that is enough. If not someone let me know.

If you happen to get the thermostat open or clogged with debris and you can see that the motor isn't getting warm, they are not very hard to clean out if you carry a few tools with you. I have had to clean mine out several times now and it takes about 30 minutes. You will need the right tools for the job and I also carry extra gaskets in the glove compartment of my truck just in case one of them tears. There are two thermostats like Jeff said but only one of them has the temp sensor. Bummer that the one with the temp sensor was fine and the other was not, but there is no way to tell because the one stuck open on you was the one without the sensor. I wonder how often that happens, having debris under the one without the sensor. Both of mine have been dirty when I pulled them apart to clean them out.

So if I stop and fish for a couple hours, I have to re warm my motor ? How many people do that ? I have a Yamaha 175 four stroke and I let it idle while I park the truck then idle out a little ways then take off. I rarely run it over 4000-4500 rpms while running to fish, sometimes rarely 5000. 40-45 mph is plenty fast for me. Great engine !

Good point. I have never checked the engine temp after I sat for 2 hours to see what it dropped to. Obviously it will cool down much faster and to a lower temp this time of year than in the warmer months. This made me think to check it more closely in the future.

This right here...that's why I have a Merc Monitor

Not usually, ambient temp will usually keep ya around 80, that said I have a temp gauge so I use it. If I didnt I would start up and idle away from my fishing area for 100 yards minimum before I gunned it.

That said your staying in a good rpm range our motors will last a lot longer at that vs beating on them at peak rpm all the time.


Its no different than your car they dont cool all the way down that fast.

It's almost 2020 and marine outboard manufacturers are years behind every other internal combustion engine manufacturing on the planet? Look at the HP to displacement ratio motorcycles are putting out today and how bullet proof they are. They have tiny cooling systems.

An outboard warmed up long enough to back it off the trailer, idle for 5 minutes while fishing partner parks truck and boards outa be ready for hammer down.

Rings sticking to cylinder walls and pulling top of piston off. Good Lord!

Jeff, so I hear conflicting info on the board on what RPM to run. I've seen people say that the Yami 4 cylinders want to run hard. Have you seen any studies on what is optimal RPMs. I run mine hard because it's a center console and wide open is 50 mph so if I ran at 4000 RPMs, I'd be in the mid to high 30 mph which would suck. Just curious if you've seen any studies on optimal RPMs for longevity.

Found this post. Yamaha tech telling this guy to run it hard. But who knows if it's really true. https://www.ultimatebass.com/bass-fishing-forum/index.php?topic=113034.0