18 hp johnson

[jasonbays]

I have an 18 hp johnson, how do I replace thermostat? I checked the pump and impeller, it is new. Not sure how to check if it's pumping water.

 

[racerone]

Little cover ( 3 screws ) on top of cylinder head.----Those thermostats are often stuck open.----If it tests good why replace it ?----Yest run in a bucket with water 8" above impeller.

 

[jasonbays]

Little cover ( 3 screws ) on top of cylinder head.----Those thermostats are often stuck open.----If it tests good why replace it ?----Yest run in a bucket with water 8" above impeller.

I don't see any water coming out the exhaust. That's why I am concerned.

 

[jimmbo]

Did you verify that the Pin/Key that links the Impeller to the Driveshaft was in place?
Also the Grommet for the watertube in the pump housing needs to be there

 

[F_R]

I have an 18 hp johnson, how do I replace thermostat? I checked the pump and impeller, it is new. Not sure how to check if it's pumping water.

It should pump water whether the thermostat is defective or not. Water will spray out the blowhole about halfway down the backside.

 

[racerone]

If the copper tube was stuck in the pump housing you have to remove it.----First install the copper tube into the exhaust housing.----Then install the lower unit.

 

[racerone]

So, was the copper tube installed correctly ?

 

[jasonbays]

So, was the copper tube installed correctly ?

Yes, but no water out the exhaust

 

[jasonbays]

Yes, but no water out the exhaust

Mabey I should tear it apart again and blow air through the waterpump shaft??

 

[tphoyt]

What do you mean by you checked the pump and impeller?
Did you remove the impeller? Did the fins straighten out somewhat or did they stay curled around? It can look new and fine but it should be soft and flexible to work properly.
Just a thought.

 

[jasonbays]

What do you mean by you checked the pump and impeller?
Did you remove the impeller? Did the fins straighten out somewhat or did they stay curled around? It can look new and fine but it should be soft and flexible to work properly.
Just a thought.

I took the impeller apart and waterpump. It was flexible like new. Slapped it back together and still no water out the exhaust

 

[F_R]

Where are you running this thing? On a bout on the lake, or in a bucket, or on muffs, or where?

 

[jasonbays]

Where are you running this thing? On a bout on the lake, or in a bucket, or on muffs, or where?

In a cattle traghth

 

[jasonbays]

In a cattle traghth

It's well submerged

 

[racerone]

Is the water 8" above the impeller ?

 

[jasonbays]

Is the water 8" above the impeller ?

12 inches above the impeller

 

[racerone]

There must be an internal blockage.----Should not be hard to figure out.-----These are wonderfully simple motors

 

[jasonbays]

There must be an internal blockage.----Should not be hard to figure out.-----These are wonderfully simple motors

Going to take the air hose to it tomorrow