I have a 2001 Ranger. It has a 2 stroke 150 Yamaha Vmax. It has been mind for 6 years. No issues. It was cherries before, and I do regular maintenance and down beat on it. I change the water pump every 2 years. Thats overkill for the amount of time I run it and the short season I have here in MA. Anyhow, this spring I got the overheat alarm. My water pump had somehow gone bad. My mechanic was shocked. He replaced the entire thing-water pump, gaskets, thermostats etc. Well, it ran fine for 3 weeks and today I got the overheat alarm again. It is driving me crazy as I'm already into the boat $3k this summer in repairs. Anyone have any idea as to what could be the culprit. My mechanic said there was a little sand in the engine when he replaced everything. My dad has the tendency to come into the ramp hot and has to give it a bit of reverse. He did that today, nothing major. Any chance that is the culprit....let me know. Thanks in advance. 

When does the alarm go off? At a certain RPM, idle, all the time?

sounds like there could be junk blocking the water flow. are the water passages in the head partially clogged? Junk stuck in the impeller, stuck/bad thermostats could cause this as well. 

Only goes off at idle speed. Thermostats are brand new. And just got the compete go thru from the marina so nothing should be clogged. 

11 hours ago, BaitMonkey1984 said:

Only goes off at idle speed. Thermostats are brand new. And just got the compete go thru from the marina so nothing should be clogged. 

Check for a stuck popet valve.

2 hours ago, iabass8 said:

Check for a stuck popit valve

^ this. Check this first before you do anything else. These are known to go bad on the 150 and up Yamaha's. It's possible it's not that, but definitely check it anyway. 

Those popet  valves  where the devil for those yamahas and the mysterious idle overheating. The popet valve and/or spring could be stuck at idle. 

So you were all correct. The posit valve was stuck. So happy its not the water pump again because I can't take another expensive repair bill this summer. Anyone have an idea as to what the cost for this repair should run at a small local repair shop? 

 

 

 Should be less than $100 between parts and labor. You could probably stand there and watch them do it it shouldn't take long as long as it's not difficult to reach. 

$260.00 for Genuine Yamaha Parts and labor.

4 hours ago, BaitMonkey1984 said:

$260.00 for Genuine Yamaha Parts and labor.

ouch. isn't the assembly like 50$?

Haven't picked it up yet, just got the final tally over the phone. But I went online and it was $30-50 for parts. 

It sounds like you need to find yourself a better marine mechanic! 

24 minutes ago, WIGuide said:

It sounds like you need to find yourself a better marine mechanic! 

x2. 

 

You got hosed on labor..or suckered. One of the two at least. If he did a good job and all is well then I guess I could live with it but his labor is outrageous on that small of a job. 

I am in a locale that their are no options. I literally have two options. The big professional marina or this guy. Big professional marina long wait time, good work, high costs. This guy work is ok, high cost, no wait. I hate it. 

Buy yourself a set of wrenches and have at it haha. No wait time, you know what was done and what wasn't. 

There's a topic here: http://www.thehulltruth.com/boating-forum/477518-yamaha-hpdi-poppet-valve-replacement-updated-pics.html

...on replacing the popet valve on a Yammie HPDI.

Looks like a few extra steps...

$260 might not be out of line.