yamaha 15hp cooling issue

ukprometheus · 22 March 2012, 22:22

ahhhhh its not peeing

Story so far
purchased this engine about a month ago and run it up to find no water comming from the tell tale so i thought to myself better it happened now rather that on the water so i started giving it a full service starting with the impellor.
after changing the impellor i still found i was getting no water up so i remove the thermostat and still the same no water.
Next onto the water ways so i remove the plate on the right of the engine which is exhaust and cooling where the tell tale pipe connects and i find a build up of salt so i clean that up and reasemble with new gaskets.
Start engine and still nothing

ahhhhhh remove leg once again and reasemble impellor housing and run on a drill in a barrel of water to make sure i have flow.
reinstall leg and hey presto a 6ft jet appears from the tell tale.
run for 15 mins and turn off and restart and no water

.
i have tried both with the thermostat and without and i just seems to want to pump when it feels like it.
any ideas anyone

Erin · 22 March 2012, 23:15

Assuming the keyway and woodruff key are not slipping in the impellor then the only other possibility is some debris that's floating about in the waterways and occasionally blocking the outlet. Have you tried back flushing?

ukprometheus · 22 March 2012, 23:18

Quote:

Originally Posted by Erin

Assuming the keyway and woodruff key are not slipping in the impellor then the only other possibility is some debris that's floating about in the waterways and occasionally blocking the outlet. Have you tried back flushing?

i have run an airline down the tell tale and it turns the barrel of water into a bubble bath

Nos4r2 · 22 March 2012, 23:33

Your exhaust gasket may be blown. Exhaust gases into the cooling system will stop water flow.

ukprometheus · 22 March 2012, 23:36

Quote:

Originally Posted by Nos4r2

Your exhaust gasket may be blown. Exhaust gases into the cooling system will stop water flow.

i think that is the one i have already changed on the side of the engine

i have been thinging head gasket for the same reason

Nos4r2 · 22 March 2012, 23:37

Quote:

Originally Posted by ukprometheus

i think that is the one i have already changed on the side of the engine

Nope, not that one.

The one between the powerhead and the leg.

ukprometheus · 22 March 2012, 23:44

Quote:

Originally Posted by Nos4r2

Nope, not that one.

The one between the powerhead and the leg.

thats not really what i wanted to hear

i bet thats a real pig to change

Nos4r2 · 22 March 2012, 23:48

Quote:

Originally Posted by ukprometheus

thats not really what i wanted to hear

i bet thats a real pig to change

Not really. The hardest thing is separating the powerhead from the leg once it's unbolted. I can do the whole job in an hour or two as long as the nuts come undone.

Drop the lower unit first or you'll never get it off

ukprometheus · 22 March 2012, 23:51

Quote:

Originally Posted by Nos4r2

Not really. The hardest thing is separating the powerhead from the leg once it's unbolted. I can do the whole job in an hour or two as long as the nuts come undone.

Drop the lower unit first or you'll never get it off

ahh ok i suppose the whole block will come off in one lump after the leg is off.

i will order up some gaskets then and give it a go.

Nos4r2 · 22 March 2012, 23:57

Quote:

Originally Posted by ukprometheus

ahh ok i suppose the whole block will come off in one lump after the leg is off.

i will order up some gaskets then and give it a go.

Yes. Once you figure out where all the nuts are to undo it and you've got the carb off or disconnected it comes off as one lump.

ukprometheus · 22 March 2012, 23:59

Quote:

Originally Posted by Nos4r2

Yes. Once you figure out where all the nuts are to undo it and you've got the carb off or disconnected it comes off as one lump.

cheers Nos

i see a plan forming

Nos4r2 · 23 March 2012, 00:04

Quote:

Originally Posted by ukprometheus

cheers Nos

i see a plan forming

It's not a hard job, just make sure the mating surfaces are scrupulously clean before it goes back together.

Course, it might not be the problem...

ukprometheus · 23 March 2012, 00:06

i do get a chuff from the tell tale and if i suck on the tell tale hose i taste exhaust

captnjack · 23 March 2012, 00:43

sucking on the tell tale is not recommended

ukprometheus · 23 March 2012, 00:52

Quote:

Originally Posted by captnjack

sucking on the tell tale is not recommended

twas yummy for sure

Nos4r2 · 23 March 2012, 01:44

Quote:

Originally Posted by ukprometheus

i do get a chuff from the tell tale and if i suck on the tell tale hose i taste exhaust

Sounds like your problem then.

ukprometheus · 13 April 2012, 01:19

well i replaced the head gasket and all seems fine now, there was a small blow between the cylinders into the water ways

now pumps water each and every start