Outboard water pumps

Hi Kev.

DOn't know where u live but up here the mud wasps love building nests in small places, we mostly carry a length of light wire in tool; kit to poke it out.
Run the motor for a minute or so.
Is the water that comes out round the prop getting hot (not warm)? If hot you have problem.
If just warm/warm. it could be a blockage is working like a 1 way valve.
Run some wire up the hole while running motor. Wiggle it round if you feel anything.
should blow it out.

The tell tale is only to let you know water is flushing system.
If system running warm it'll be no bug deal.
Is impellor on shaft solid or can it rotate by hand?. You got a problem. did you replace stainless sleeve? with impellor. Some do, some don't.
If no obvious blockage and running hot or impellor spinning on/with shaft.
Take it to mech. Don't ask blokes like us "users" on here. We could cost you with our advice.
Have fun

I keep a short length of 2mm dia whipper snipper cord in the boat to clean out the telltale - stiff enough to poke, flexible enough to go around corners, plastic so it won't corrode or do damage.

As to your exact problem... no, can't be sure. As suggested, take it to a pro. I have a local service guy that doesn't charge for quick advice on the assumption that I am likely to go back for a more major job.

Good luck,
glids

There is a Thermostat ,this may be the problem.... you can get away with not replacing it depending on different factors.... Google up the manual http://www.yamaha-motor.com/assets/service/manuals/1/lit-18626-06-91_1392.pdf

Did you run it long enough in the drum of water for the thermostat to open? At idle, my 15HP needs nearly a minute before the tell tale shows.

Iza

Well I have finally got this problem sorted. On the up side I'm quite good at taking the bottom end off the motor now and even putting it back on, including connecting up the gear selector rod.

Thankyou to everyone for your help. I think the problem was a combination of 2 factors. Firstly when assembling the pump housing, I managed to put an extra gasket in. I think this may have altered the action of the pump. Secondly I experimented with the depth the motor was dropped into water. I found that over the intake up to the first fin on the leg did not work. However if I dropped the leg lower into the water, water started to pump. Looking at how the outboard sits on the boat, I have come to the conclusion I had it too far up in the water. 50mm makes all the difference. I assumed that if the intake was below water level all would be fine, but it appears this is not the case. I now have a really good stream of water coming out the telltale. I am going to get a proper drum to run the outboard in and do some more testing. Incidentally I was worried I may have damaged the new impeller, but when I assembled it I smeared it with rubber grease. The impellor looks perfect despite much info telling me the impeller should be damaged from running dry, even though for a short period of time.

Regards

regards Kevin