2006 Yamaha 90 2 Stroke - Tell Tale/Impellor issue

[Deleted]

OK i just bought a 1800CC with a 90 Yamaha 2 stroke on it. ( both model year 2006. When I bought it the tell tale was not pumping water. The guy said he would have the impellor replaced which I figured it was. He said the dealer did it. Well today I started it for the first time with the muffs on and the water ran for about 30 seconds at low pressure then stopped. Then I ran it in a tub and it did the same thing. Well I then took the boat to the ramp and back the boat in on the trailer so I could run it under power. Well turned it on no water out of tell tale. then i put it in gear and ran it around 1500 RPM, the water flowed under very low pressure. pushed it to 2500 for about 10 seconds with no change in pressure. put in neutral and the flow stopped. Before going I took the screen off to look for obstructions, and when I returned home I ran a wire in the head, nothing also was able to blow through the tell tale tube with out a problem.

I assumed that they didn't change the impellor, however the guy I bought it off says they did and then one they removed only had two paddles on it. I looked at the bolts and it appears they removed the lower unit because all the bolds have some grease near them and some fresh grease can be seen along the lower unit plate.

I guess I can pull the lower unit and take a look. Is it possible the impellor is on backwards, I know on my old ox66 it was impossible to put it on backwards. Any thoughts?
Thanks
Pete

[Juan]

Certainly sounds like an impeller problem... and yes it could have been installed backwards... if that was done (placing the impeller paddles in the wrong direction) then the impeller could have been damaged when the motor was turned over....thus no water pressure.... it aslo could be that the impeller housing is worn. It's usually a good idea to change the entire water pump assembly (impeller and housing) if your having pressure issues...

ps. even if the impeller was installed backwards, they will usually reverse themselves ...but it may take a while and there's the possibilty the impeller could be damaged during that process...so my guess would be a worn impeller housing.

Did you get a high temperature warning when you ran it?
Are you running it for at least 30 seconds? (They don't pee instantly)

[Deleted]

Yes, I have run it for a few minutes and the water starts but after about 20-30 seconds it stops. The old impellor only had 2 vanes on it according to the Yamaha tech, He replaced it and then started, he said it ran fine, but he must have run it very long because after 20-30 seconds it stops. I think some of the old impellor must be in the water tube leading to the head. I;m going to pull the lower unit this weeken and have a look.

[T-Topless]

Check to make sure you don't have sand plugging the tell/tale (pee) hole ... happens a lot on Yamahas, which use a a fitting with a fairly small hole (guess about 0.080" ID).

[Deleted]

I checked the pee hole and can blow through the tube. It must be a piece of old impellor vane in the water tube. I have to pull the lower unit off to further investigate.

[Deleted]

Pulled the lower unit off finally and it appears when they changed the impellor they put alot of heavy grease around the housing. A big glob got up into the water tube. I cleaned it out and now if blows harder than a fire hose.

[freezerfiller]

That's great news! Stinks you had to do it yourself to get it done right, but you know what they say...