Post Impeller Change Observation (15hp 2 stroke)

[Fishheadbarandgrill]

When running the engine after changing the impeller I noticed that there was water coming out where I don't remember it doing this before. This is only the second time I've run the motor out of the water. Water is coming out of the front just above the lower unit and out of what must be weep holes on the back side of the lower unit. I'm getting good pee water out of the head. pix included. is this normal?

I also put a little bit of lithium grease on the 4 bolts on the impeller housing body and the 4 bolts on the lower unit. Was that a bad idea?

Thanks,
Bob

[dray0151]

If you give the complete model number and year others will help you. Such things as the wear plate or housing if applicable may have needed to be replaced if you did not. The grease on the bolts I am not sure of, maybe didn't stay tight, or if one of the o-rings did not seat? Did you buy a kit or just the impeller?

[Fishheadbarandgrill]

The model is a 15FMH (US version would be 15MSH). I only replaced the impeller. O-ring looked in good shape.

[dray0151]

You are probably in for a do over and replacing some of the parts with a kit to be sure things like the housing and o-rings are good. My service manual tells me that on both sets of bolts I should be using loctite not grease, might be part of your problem as something is not tight. did you have the torque specs for the bolts? I will leave the rest of a response to more senior members on here for help.

[Fishheadbarandgrill]

I don't have the torque specs. The bolts are tight so I don't think loses bolts are an issue. I will remove the grease though just to make sure. I noticed that here kit doesn't include the o-ring which I thought was strange.. at least it's not shown in the pictures of the kit.

[dray0151]

If you go to this web site they have good manuals available so you can see what all the parts and specs are and what to use I think such as loctite on bolts.

https://www.vansoutboardparts.com/

Go to the bottom of the page and find the link service manuals and then on the right hand side the link Yamaha manuals and then locate your US model by the year and model. The European model I assume would be the same. you can also see a gasket at the bottom that my manual for a F115 says is not reusable, don't know about yours.

Again as some of the other more experienced guys on here come around you may get more advice.

[Fishheadbarandgrill]

Thanks. I've got a rebuild kit plus an o-ring on order now.

[DennisG01]

There's no question you need to drop the lower and take a look, but that part you already knew. As you were thinking, that's a lot of water to be leaking out there. There's no way the bolts loosened up that far, that quickly. I always use some type of grease (multiple types of engines) and have never had the bolts back out. Not saying it couldn't happen, but it's very unlikely to happen over the course of a few years - zero chance it would happen in the short time you had it there.

Could be an issue with the housing - possibly even the water tube. Most likely, you'll be able to figure it out easily enough once you drop it.

[TownsendsFJR1300]

I don't remember seeing that much water come out of there... Perhaps the seal for the water tube moved.

Here's a short video of mine on muffs, no water from there(F150):
https://www.flickr.com/photos/147134...in/dateposted/


As for grease on the bolts, if used in salt water, out resident MT does NOT use loctite (as per the manual).


I put just a light coating of Yamaha's water proof grease on the threads of the WP housing and snug it down. Same for the mounting bolt threads. You won't find a torque spec for that WP housing either as there is NONE officially.

[panasonic]

I don't remember seeing that much water come out of there... Perhaps the seal for the water tube moved.

Here's a short video of mine on muffs, no water from there(F150):
https://www.flickr.com/photos/147134...in/dateposted/


As for grease on the bolts, if used in salt water, out resident MT does NOT use loctite (as per the manual).


I put just a light coating of Yamaha's water proof grease on the threads of the WP housing and snug it down. Same for the mounting bolt threads. You won't find a torque spec for that WP housing either as there is NONE officially.

I agree with FJR1300...the seals where the water tube enters the water pump are dislodged and not all the water is going up the tube to the engine...Drop the LU down and I am sure you will find it easily.

NO Loctite on those bolts, there is absolutely no need of it in this case, grease is your friend on outboard motors.

If your stuck on torqueing those bolts there should be a reference to "standard" torque in the Service Manual near the beginning ( go to the site already mentioned to download) and a torque will be given for that specific size bolt.

[dray0151]

As for grease on the bolts, if used in salt water, out resident MT does NOT use loctite (as per the manual).

Should have clarified this is Loctite 572 a thread sealant that is not the red from hell loctite

[pstephens46]

Don't put that on your lower unit. Little grease is good on bolts.

[Fishheadbarandgrill]

Thanks all. I will drop the lower unit in the next day or so and see if the water tube is the problem.

[Fishheadbarandgrill]

Okay. Just looked at pictures of the seal that is suppose to be on the water tube. I don't remember seeing that when I re-assembled (or when I removed) the lower unit. Maybe is fell off when I removed the lower unit. I'll have a look tomorrow and if I don't find it, I guess I'll be ordering one.
Geeze!

[Fishheadbarandgrill]

Problem discovered. The rubber insert that goes on top of the pump housing had come out and was stuck on the water tuber so it wasn't making a seal. Also the seal that is suppose to be on the tube was missing. Order date tube and fitted the insert on top of the pump and all appears to be well with the water flow.