Tell tale peeing well but nothing coming out of exhaust housing on Johnson 1979 15hp

[snapper1]

Do what you like , have time for.

Your suggestion makes good sense and I have time as the weather here for the next few days is not good for taking the tinny out. Thank you.

 

[snapper1]

If the thermostat has failed in the open position, shouldn't the water have still expelled from the exhaust housing too?

yes

Thanks for your help too kbait.

 

[kbait]

I personally would test run first.. why fix what ain’t broke.

 

[snapper1]

Yes, as soon as the weather allows me too I will give it a run on the water with a new impeller and hopefully all will be good. Cheers to both of you.

 

[snapper1]

I put a new impeller in the motor and ran on the water and no overheating. Motor ran fine with strong tell tale discharge.
So, water must not exit the block and out of the exhaust housing/lower unit passage until it warms up sufficiently to allow the thermostat to open and then escape once it's able to run through the water cover discharge path.

 

[kbait]

Yes, exactly.

 

[snapper1]

Thanks Kbait. I was wondering why other later models with functioning thermostats that were not stuck open would still show water discharging down the exhaust together with the tell tale, when just running a hose connected to the copper water tube (so leg off and not running).
I think it could be because they have a spring attached to the thermostat and with increased water pressure it forces the spring to compress and allow water to discharge.
With this 1979 model there is no spring and that will not allow water to discharge through the exhaust housing testing this way.