Muffs

[Mike M]

Hi everyone, hope someone can help me here. I have a yr 2000 70 HP Yamaha 2 stroke motor which i am worried about overheating. A while back i got into some very shallow water in the fog while while picking up crab pots which ended with a lot of sand in the engine. I removed the head and all the covers and made sure everything was flushed out and all jackets clear, i also removed the lower leg, put a new impeller in, fitted a hose to the pump outlet, removed the thermostat and flushed to make sure it was clear then checked and flushed the lower leg, then put back together. I have tried dual rectangular and dual round muffs, single round and rectangular muffs and i cannot get water to come out the thermostat housing with the muffs on whether the motor is going or not. Can someone give me some advice on this as i have had the lower leg off about 6 times and cannot find out why. look forward to your advice. 

[noelm]

Best guess is simply not enough water pressure, put it back together and try it in the water, chances are it will be OK.

[dmck]

Run it in a tan wher you have access and control.

[Mike M]

2 hours ago, dmck said:

Run it in a tan wher you have access and control.

Works good on water just that all the muffs which are new leak very badly

[Plethora]

Poke a piece of wire down the water outlet and wriggle it back and forth till the water comes out - I had a bit of weed in mine once

[XD351]

Did you clean out the mesh screen in behind the water pickup? Are you sure the water pump is assembled correctly ? I don’t know about a 2000 model but on my 2003 40hp there is a small hole ( around 3 mm dia ) just above the water pick up and when using muffs there has to be water dribbling out this hole when you turn the tap on .  If you have a vise handy you could squeeze the steel fork on the muffs to close it up a bit and it will apply more pressure to the muffs - helps them seal better .

Edited November 22, 2022 by XD351

[zmk1962]

5 hours ago, Mike M said:

Works good on water just that all the muffs which are new leak very badly

Am I understanding correctly- you’re getting water out of the tell-tale when in a tank … but not on muffs  … is that right?

Cheers Zoran 

[Fab1]

9 hours ago, Mike M said:

Works good on water just that all the muffs which are new leak very badly

If it works good in water and not on the muffs the issue is muffs leaking not providing enough water pressure.Did it work on the old muffs?If it did again the muffs are no good.