Just to be clear, you changed the impeller after this started happening? Or did it you change it for regular maintenance and then it would not pump?

Please provide full model and Serial number from ID tag on the mount bracket, it may be useful information.

The motor is a 97 Yamaha 40esrv 3 cylinder. Yes, I changed the impeller in response to it completely stopping.

Have you been running your engine in dirty water, sand , mud ect.? Before this started to happen. Thinking you may have some debris sucked up into your engine...

Yeah, we run on the Pearl River. That's all it is, sand and muddy water. But I pulled the screens and checked under the impeller housing... no debris. Also, I put the hose up to the copper water tube when the foot was off, and it flowed fine. From what I can tell, it's like it's not getting a good seal or something. There's water coming out the two holes on each side of the housing and out of the exhaust.

Is the engine getting hot when the telltale stops peeing, you see steam coming out of the telltale?

If engine is not over heating, just no water from telltale?

Here is what I would try first. I am assuming the boat is on a trailer. Pull the lower unit again. put a clean garbage bucket under the leg.

Take the thermostat out, use your garden hose, with something on tip to make as good of a seal as possible with the thermostat housing, and back feed the water through the engine block back down thru the water tube/exhaust.

Try not to get water all over you electrics when flushing thru thermostat hole.

Catch the water you flush down through and inspect it for sand, fine dirt.

I think you have some dirt up in there somewhere and at idle the water is not flowing fast enough to pick it up and move it. When you speed up the water going through system is much more and moves the debris around and plugs off the telltale port.

If there is dirt in there, you don't want to flush back down into your water pump, thus removing the lower unit. While lower unit is off you may want to take off impellor housing again, make sure everything is good there, seals, wood drift key that the drives the impellor is there..ect

Please see attached video for reference on telltale problems.


https://www.youtube.com/watch?v=dx8_xP30aSY&t=848s

what parts did you use when replacing the impeller?
Yamaha pump kit has the cup and wear plate included.

Housing would need replacing also if there is any signs of melting of the plastic.

if you used aftermarket parts they may not fit properly

Thanks, I guess that'll be my next effort.

I used all yamaha parts. Initially I just replaced the impeller. Then I ordered the little damper/water seal on the top of the housing that the tube slides down into when you out the foot back on. Also, the gasket between the housing and metal plate underneath the housing. All from Boats.net.

that metal plate and cup the impeller rides in/ against wear along with the impeller when in silty(muddy/sandy) water.
they seal against each other and are wear items that need replacing.

there is also a rubber dampener that seals the exhaust gasses running out of the lower unit/prop area from getting to the water pump intake.
there is a aluminum support that likes to corrode and swell up not letting things seal well.

#26 and #27 in this link
http://www.boats.net/parts/search/Ya...202/parts.html