water circulation problem

[hendo]

15HP yamaha 2 stroke aux, i have bought new impeller and housing, removed thermostat yet still have no water circulation, please help!!

[marshmat]

As in no water coming out the pilot hole?
1) Make sure the motor's lower unit is fully submerged to its design waterline when you're testing it. If it's sitting too high the pump might be sucking a bit of air.
2) Make sure the pilot hole and cooling passages are clean. The pilot hole can be cleaned with an unfolded paper clip. The cooling passages can be back-flushed under pressure by a dealer.
3) Clean the intake screens and make sure nothing is bent or clogged down there.
How old is the motor?

[hendo]

hi thanks for the advice i dont know the age of the engine, its cdi ignition if that helps, i have took the gear box off and put a hose straght on to the water pipe up the leg. i took off the thermostat housing and tride to blow water through the engine but it was solid no water came through the thermostat housing at all. my out board experience is limited to what i have learned today is there a chemical flush you can buy hope you can help
hendo

[stonebreaker]

Every spring, we had to do the paperclip thing on my dad's bass boat. Dirt daubers (mud wasps) built a nest in the motor's water outlet every year.

[tom kane]

If you have put water up the inlet pipe with the gbox of,check that water has not got into the bore through a rusted out cylinder bore.even with clear water ways and good pump impeller the compression stops the water from circulating.

[globaldude]

the point made by Mashmat was to " BACK flush" the engine, not try putting the water through it the same way as the water pump - " I took off the gearbox and put the hose up the water intake" -- that would just push any obstruction / debri further into the cooling system !!.
The objective of BACK FLUSHING is to dislodge blockages in the reverse order they were lodged .
Have you got it working yet?, it's been a while .

[tom kane]

Back flushing an outboard is not a good idea as the water may go where it is not intended to go,like straight into cylinders through the exhaust ports from the silencer if too much water is applied at the wrong place.

[Frosty]

Remove the engine cover and the tell tale pipe( thats the rubber pisser pipe that shows all is well). Wriggle about a piece of wire in the cylinder block hole outlet ( like stonebreaker says) It very often dries out and cruds up.

I have in the passed sucked at this pipe while the engine is running.