Suzuki DT40 - not pumping water

[frankmachine]

Good day all

I have a 1989 DT40 which produces no tell tale water jet at all. I appear to have the motor running nicely and all the top end looks and sounds like it’s in good order. I have dismantled the leg and inspected the water pump, plate, gasket and key which all look to be in reasonably good condition. I have blown compressed air up the tube inside the leg and air flow is all good everywhere I have fired water into the thermostat housing and this does indeed then come shooting out the tell tale, so I am fairly sure there are no blockages anywhere, it just wont send water up with impeller. The only thing of possible concern is the area of casting upon which the impeller gasket sits is a little corroded, (pic attached) but I still fail to see how we are getting NO water jet at all…… The gearbox oil looks to be in fine condition too, not milky.

Any thoughts out there?

Thanks
Frank

 

[Sea Rider]

Welcome to IBoats,

That's a 32 year oldie motor, it's a fresh or salted water used motor to start with ?

Happy Boating

 

[frankmachine]

Welcome to IBoats,

That's a 32 year oldie motor, it's a fresh or salted water used motor to start with ?

Happy Boating

yes well done. it's saltwater. the motor is overall in very good condition, just impeller doesn't seem to want to pump up..........

 

[Sea Rider]

Can you imagine the huge internal salt formations that's been growing in inside the whole water cooling system in 32 years of use. What you can do is : put the lower leg into a container with a high water level, connect a drill machine at upper splined drive shaft to turn CW, check if the water pump pumps a good amount of water out the upper rubber grommet.

Remove the thermo from its housing, bolt lid back on, connect a water hose on the water pick up tube that connects to the water pump and flush the motor for 30 minutes, if the house counts with an outstanding water pressure the better. Bolt the lower leg back on, start the motor, now pumps much better ? A motor in mint external condition doesn't say much, what really matters is the internal overall condition.....

Happy Boating ​

 

[racerone]

Are you testing in a bucket.----If so the water level must be 8" ( 20 cm ) above the impeller.

 

[frankmachine]

Are you testing in a bucket.----If so the water level must be 8" ( 20 cm ) above the impeller.

Yes I have been testing in a bucket and also with flush muffs and even firing water into the flush plug hole with water blaster... as yet nothing........

 

[frankmachine]

Can you imagine the huge internal salt formations that's been growing in inside the whole water cooling system in 32 years of use. What you can do is : put the lower leg into a container with a high water level, connect a drill machine at upper splined drive shaft to turn CW, check if the water pump pumps a good amount of water out the upper rubber grommet.

Remove the thermo from its housing, bolt lid back on, connect a water hose on the water pick up tube that connects to the water pump and flush the motor for 30 minutes, if the house counts with an outstanding water pressure the better. Bolt the lower leg back on, start the motor, now pumps much better ? A motor in mint external condition doesn't say much, what really matters is the internal overall condition.....

Happy Boating ​

So are you basically suggesting a likely blockage somewhere?

 

[frankmachine]

got it running, it needed deeper water around the leg to push water up. thanks all!

 

[racerone]

Good work.

 

[99yam40]

got it running, it needed deeper water around the leg to push water up. thanks all!

that does not explain why it did not pump when on muffs, can you explain that?

 

[racerone]

Some motors are shy when running in a hose.-----And not all volume / pressure from hoses is the same.----And water under pressure has a lot of air dissolved in it.

 

[raczekp1]

this suzuki dt 40 have bad designe a water pump outlet tube. its breaking at the top( under powerhead)