Force 120 over heating

[Racewerx]

My L drive is over heating and I have a strong steady stream of cool water coming out the back. I removed the thermostat (it was open) and the water seemed a bit warmer but the power head was still getting hot. Anyone have an idea what is going on here?

 

[bentle]

Re: Force 120 over heating

What year is your outboard? Also are you running with muffs or in the water? When was the impeller changed the last time? May need to remove lower unit and back flush through thermostat opening with motor not running. The water passages could have dirt, sand and debris plugging water passages. Also make sure exhaust bolts are all in place. Torque to 70 inch pounds . That's about 8.4 pounds torque. Anymore and you will strip aluminum threads. Take thermostat out and boil some water then drop it in the water and double check that its opening properly.

 

[Racewerx]

Re: Force 120 over heating

The motor is a 1990 L drive.
It has no muffler just goes into water.
The impeller was just replaced before this problem started.
The themostat is working fine I did test it.
The motor shoots a strong stream of water out of the back but it is cool to the touch as if it is not curculating threw the motor.

This problem really has me stumped.

 

[baylner_boy]

Re: Force 120 over heating

I am having a similar issue with my 1990 L-Drive 120. I was able to get the thermostat out and test it. It does open, but I'm questioning how far exactly is it supposed to open. Mine only opens up about 1/8 in. or so when put into 200 degree water.

When I run my boat water, the exhaust gets very hot. If I run it long enough, I fear it will again melt a hole the exhaust coupler(s) that are made of a rubber type material (marine exhaust hose). I'm thinking there is a restriction somewhere preventing water from circulating properly, but haven't quite pin pointed the issue yet.

 

[Jiggz]

Re: Force 120 over heating

I am having a similar issue with my 1990 L-Drive 120. I was able to get the thermostat out and test it. It does open, but I'm questioning how far exactly is it supposed to open. Mine only opens up about 1/8 in. or so when put into 200 degree water.

When I run my boat water, the exhaust gets very hot. If I run it long enough, I fear it will again melt a hole the exhaust coupler(s) that are made of a rubber type material (marine exhaust hose). I'm thinking there is a restriction somewhere preventing water from circulating properly, but haven't quite pin pointed the issue yet.

What about just removing the thermostat all together and see if the overheating goes away? Then you can tel if its a thermostat problem to start with. If the overheating doesn't go away after removing the t-stat then there is a clog somewhere. Then do the back-flush as previously mentioned. If you cannot back flush, there's obviously a clog.

 

[fucawi]

Re: Force 120 over heating

Why did you change the impeller ..did it disintegrate and send bits up the pipe towards the engine? Blow out with compressed air up the pump outlet pipe...in the end result you may have to take off the exhaust cover plate and clean out the small water ways

 

[baylner_boy]

Re: Force 120 over heating

update on my issue - I think the problem was definitely the thermostat. I had to wait for a new gasket and such, but once I got the new parts, I tested the new thermostat to compare how far it opened versus the old one. The new one opens way further, so I'm sure that is what the problem is now. Ran the boat in water today, and I could feel the exhaust get cooler once the thermostat opened up.