How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Jason Your Own Question
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 15635
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
Type Your Boat Question Here...
Jason is online now
A new question is answered every 9 seconds

I have a 2013 yamaha 150 4 stroke outboard. Over the last 2

Customer Question

I have a 2013 yamaha 150 4 stroke outboard. Over the last 2 years it won't "pee" when I first start it until I rev it up to 1500-2000 rpm. I just replaced the lower unit. Refurbished lower unit but new water pump. When I launched it the first time it peed immediately. I left it idling for a couple minutes and it quit peeing and the alarm came on. After I let it cool off a while I started it and revved it a little but it wouldn't pee. I went to put it back on the trailer and when I revved it enough to get it on the trailer it started peeing.
I drove it around a bit at idle and it seemed fine so I drove it to my house and put it in my boat lift. Then when I went to take it out again it won't pee even if I rev it up in neutral. If I put the water hose on it pees fine, but in the water it won't pick up water.
Any thoughts?
Submitted: 8 months ago.
Category: Boat
Expert:  Jason replied 8 months ago.

Hi John, my name is Jason.

I read everything you wrote. Has the water pump been re-checked by a certified Yamaha technician yet?

Customer: replied 8 months ago.
No. It's brand new. First time in the water. But I had similar problem with the last one.
Expert:  Jason replied 8 months ago.

Okay. If you were to go and start it right now what would happen?

Customer: replied 8 months ago.
It won't pee. Even when I rev it to 2000 rpm in neutral.
Expert:  Jason replied 8 months ago.

Does it over heat as well as not peeing? Or does it run a normal 160F or so?

Customer: replied 8 months ago.
The first time the overheat alarm came on. Since then I don't let it run long enough to overheat. I don't have a temp gauge.
Expert:  Jason replied 8 months ago.

Okay if it's overheating and not pumping water the impeller needs to be checked again. Not just the impeller, but also BOTH orings on the water pump. If either oring is leaking or pinched, the impeller will suck air in instead of pumping water up. Was your impeller done by a certified Yamaha mechanic or somebody else?

Expert:  Jason replied 8 months ago.

That firs line should have said "if its overheating and not pumping water"

Customer: replied 8 months ago.
I bought a refurbished lower unit from Mariners Warehouse. The pum came already installed. A mechanic installed the lower unit for me.
Expert:  Jason replied 8 months ago.

Either way, people/mechanics make mistakes all of the time. The problem is going to be something wrong with the installation of the water pump assembly. I can't tell you exactly what the issue is, but common issues would include but not be limited to the impellers vanes being installed in the wrong direction, somebody forgot the key that locks the impeller to the drive shaft, the pump housing is cracked, one of the two orings slipped out of place, (happens all the time) warped base plate, somebody forgot the metal locking collar (happens al the time as well) . The lower unit needs to come back off and the installation of the pump needs to be gone through again. That's what needs to be done. Did you have any further questions for me on the issue?

Customer: replied 8 months ago.
I don't understand why I have had this problem on three different pumps. This one being the worst. Could they all be put together wrong?
Customer: replied 8 months ago.
Also, when I revved it enough to put on the trailer it started pumping and continued to pump, even at idle, until I turned it off.
Expert:  Jason replied 8 months ago.
Chances are it's not a problem with the pump, but rather it's a problem with the person doing the pump. I'm adding a picture. See attachment. What i'm adding is a cooling water flow description that comes from the factory service manual from this engine. If you look on the bottom right you will see "Cooling water pilot hole". The pilot is your pee hole. If you look at the diagram very carefully.... If there was some sort of clog in the fuel cooler, or the exhaust cover, you would loose your pee but the engine would still run cool. But because the engine also overheats, that is a sign of there is no flow from the water pump. If any of the gasket are bad on the pump, if either of the 2 orings are bad, if the metal locking collar isn't in place or not done correctly, all of those things will cause the pump to want to suck in air instead of sucking in water. Yamaha water pumps are finicky and picky. If this was a Mercury or an Evinrude you could forget gaskets or forget parts and it would still pump water, but not on a Yamaha. I couldn't tell you how many times Ive taken these apart even they were supposedly "done correctly" and there is a problem with the oring between the bottom of the pump cover and the top of the steel pump liner.
Expert:  Jason replied 8 months ago.

I don't know how you want to leave this but that is where you stand on your end and what needs to be checked. I think that should do it but I work for tips so I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

Questions do not close out, so if you have to come back later on with follow up questions to the issue you still can even after doing a rating.

Thank you

Expert:  Jason replied 8 months ago.

Hi John, just checking in. No rating has been put through for me yet, Did you have any further questions on the issue?

Related Boat Questions