1989 Johnson GT150 not cooling.

[sundaydrive86]

I fully rebuilt the engine and water pump fired it up and no water seems to be cooling the block. Is the first place I should look back at the water pump? Meaning drop the lower unit and make sure everything is good to go? Or is there a easier way to diagnose the issue, like lets say a thermostat? Any guidance would be awesome. Thank you.

 

[emdsapmgr]

Once cooling water is pumped up to the block, the first place you will see water at the block is at the telltale. Make sure it is not plugged.

 

[emdsapmgr]

Once cooling water is pumped up to the block, the first place you will see water at the block is at the telltale. Make sure it is not plugged. Is the impeller key in the correct position?

 

[Cdkarem]

Thermostats?? That's where my 1988 90hp was clogged.

 

[sundaydrive86]

So here is a new one. I isolated the clog.
I removed the engine block from the lower half of the motor. I also removed the lower unit. Water pump checked out good. But water is not being transferred from the pump to the engine block. There seems to be no clog in the copper pipe itself. but once it gets inserted into the casting from there to the engine block there seems to be a clog.

 

[sutor623]

One thing I did before reinstalling my freshly rebuilt powerhead was remove the midsection and replace the gasket and grommet that holds the copper tube in place, as well as clean the copper tube up real good.

Did you end up pulling the powerhead off again???

 

[sundaydrive86]

Sutor,
Yes had to re-pull powerhead. The sequence of events went like this.
Complete powerhead rebuild.
Installed on boat.
Fought with CDI Spark issues the last 2 months.
Finally got spark and fire but no water to cool.
Pulled lower unit to check already rebuilt water pump to find that there was no issue.
Pulled thermostats and replaced.
Finally pulled powerhead and lower unit again to find clog in mid section but can't seem to get clog to unclog.
I have never had this much bad luck.

 

[sutor623]

Maybe that clog is what toasted your motor in the first place?

Do you have a pressure washer? Have you completely disassembled the adapter plate from the midsection? Do you have a service manual? Once you get it all apart and clear out the clog, replace the water tube gasket and grommet and be done with it.

I pulled my midsection apart simply because I had it broken down to about there with the powerhead off that I just did it for peace of mind. Good thing is once you have this done you will be good to go!!

Matter of fact, I think it was emdsapmgr that convinced me to do it since I was already so close!! Thanks for that man!

 

[sundaydrive86]

I will let you know. Thanks for the info.

 

[sundaydrive86]

Good Morning,

The clog is not what toasted the motor. Unfortunately, this motor became a victim of a mouse infestation and they made a nest in the engine itself. They went up the exhaust and got into one of the cylinders on top of a piston. This happened in storage over several (7) years. Once I got the engine (for free) it was froze solid and I tore it down and rebuilt it. It has just been problem after problem.
I took the copper pipe out of the grommet that holds it in place and found a clog in casting as soon as it turns a 90? bend. I used a screw driver and other tools to remove what seemed to be a very thick clog. I will now have water to cool engine. I wouldn't have imagined that it was this involved of a water cooling issue. I hope this post helps others in the future. Thank you.
Todd

 

[sutor623]

Cool man, glad you got her!

 

[sundaydrive86]

No Title

Thank you to everyone. My boat is now up and running. Time to fish.

 

[sutor623]

Awesome, enjoy her!!