1991 15 hrs will not piss

[johnmarcous]

Recently pulled power head and rebuilt lower unit to free the shaft up. Motor has new impeller and water pump gaskets. I took off the thermostat housing, water is gushing out of that (the tube is lined up). I pulled the cooling water pilot hose, water gushes out of that. I pulled the cylinder head off, it's all clear. When I blow air into the small hole (left side) inside the thermostat chamber, air blows freely out of the piss hole on the back of the motor. I know there is plenty of water flowing through the engine, but can't figure out why it's all going out the prop and not mixing with exhaust / pissing out correctly? This is my first time overhauling an engine (of any kind) - it's starting on the first pull, running well... but it's not working as intended and I feel like I've missed something obvious? Thanks.

[99yam40]

what you did not put a pump kit on just impeller and gaskets?
Best to replace cup and plate also that come in kit

[bumperfood]

I took off the thermostat housing, water is gushing out of that (the tube is lined up). (impeller seems to be doing its job)I pulled the cooling water pilot hose,(what is that?) water gushes out of that. I pulled the cylinder head off, it's all clear. When I blow air into the small hole (left side) inside the thermostat chamber, air blows freely out of the piss hole on the back of the motor. I know there is plenty of water flowing through the engine, but can't figure out why it's all going out the prop and not mixing with exhaust / pissing out correctly? This is my first time overhauling an engine (of any kind) - it's starting on the first pull, running well... but it's not working as intended and I feel like I've missed something obvious? Thanks.

It appears that you are pumping sufficient water. Is there water coming out of the telltale? If not disconnect it at the side cover, to verify. You seem to running it on muffs, if that is the case you may not see any water mixed with the exhaust as there is no water pressure to overcome as there would be if you had the engine leg in water. Try running it in a barrel ans see if that makes any difference.

[johnmarcous]

Thanks

I am running in a 55 gallon barrel - not muffs. I am not 100% sure what the tell tale is - but I think the manual calls it the pilot hose (off the side cover) and it's got a strong, steady stream of water coming out.

[99yam40]

what motor are you speaking about?

If you are worried about water coming out of the idle exhaust relief ports, my C40 does not have any coming out either. I worried about it at first as all of the Johnierude motors I had owned in the past always had a lot of water flowing out of them. But looking at other Yamahas they only had a mist coming out if any at all.

[johnmarcous]

Thanks - it's a 1991 Yamaha 15 two stroke. Perhaps spray / mist is all I'm going to get then?

[99yam40]

Sorry, I thought the title said 15 hours

Had not seen HRS as a model # before

Might want to see if you can look at other 15s to see what they put out to be sure