# Evinrude 150 lower unit getting too hot..



## Captain WhupAss (Nov 8, 2007)

I have an Evinrude 150 that is acting up. I can launch the boat and take off and operate normally. But, after idling through a "no wake" zone for several minutes, the engine will only let me go about half throttle when I'm exiting the no wake and trying to get to full speed planed off.Quickly afterwards, I will get an alarm sounding off. If I try to crank it immediately in neutral, I still only get about half throttle.

I trimmed the motor all of the way up and felt the lower unit was very hot. After I sat and let it cool for about 5 minutes, I can crank it up and run it like normal.

The impeller is pretty new and I'm getting a good hard stream of water, so the upper is cooling fine. I changed the lower gear oil at the beginning of last Summer (May 07), but I used the boat a lot up until it got too cold to get out on the water.

I plan to check the lower gear oil tonight to see if it's low or what the deal is. Could either low or worn out gear oil have this effect?

Any ideas - SWAGs etc?

Thx!


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## sosmarine (Sep 28, 2007)

Your alarm has nothing to do with the lower unit. That is either over temp or oil pump/VRO if equiped. When the impeller was changed, did you changed the thermostats too.


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## sealark (Sep 27, 2007)

If you have system check with the lights on them when the alarm goes off the light corresponding to the problem will stay on. It sounds to me like you have a clogged thermostat it has happened to me once. I had to take the thermostats both out they are plastic plugs on top of the heads on each side. Then run the engines on a hose to flush the block our. I tried removing the thermostats and just letting the water pressure flush the block but it just wasent enough pressure without the engine running. When you take the thermostats out look at them and see if you can see sand or something clogging the very small pores of the thermostat. If you see any flush it because when you shut the engine down the sand will fall back into the block . Then reclog it when you restart the engine...


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## Captain WhupAss (Nov 8, 2007)

SOSMarine & Sealark:

Thanks for the advice. Actually I purchased the boat and motor just after a complete rework/service of the motor was done, so I don't know if the thermostats were changed out at thattime.

It is oil injected, but it appears to be drawing the oil ok. Sand sounds like a good bet. In fact,I ranintoa really shallowarea one time (a couple of years ago)and had a good bit of sand get in the block, whichtook a while to flush out.Plus, we've already been to Crab Island 3 times this year which always kicks up a lot of sand off the bottom.

To flush it like you mentioned- should I use the ear-muff type flusher or use the connector that allows the hose to connect to the back of the engine just under the cowling. I remember last time using the muff type flusher and a lot of sand coming out of the hole where you'd connect the hose to. 

I'm going to do the flush and change the gear oil in the foot, since it's time to do that anyway. Thx for the help.:bowdown


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## sosmarine (Sep 28, 2007)

Use the flush Muff. I recommend always using them instead of the rear adapter. If you use the adapter don't run the motor. 

Check the magnetic plug when you drain the lube.


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## sealark (Sep 27, 2007)

Yes use the muffs and completely remove the thermostats and leave them out for a few minutes of flushing to get the sand out of the block. You might try and put something under the thermostat opening to direct the water from the engine while it is running. Like I said I tried flushing mine out without running the engine and it gave me the buzzer again on the next trip. After running it with therms removed It never did it again and there was a lot of sand and shell in the water comming out of it...


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## Captain WhupAss (Nov 8, 2007)

Sounds like a good plan.. I'm going to give it a try this afternoon. I got side tracked last night and didn't get to do anything to it.

Thanks for the advice. I'll get back on here and post the results after I get it flushed out. Are the thermostats screwed into the top of each block. I haven't taken a look yet, so I'm not sure yet what to look for, but I do have a repair manual I can refer to find them.

Thx much!


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## sealark (Sep 27, 2007)

Yes they are on my 175 plastic round plugs about 1 1/2" diameter on the top of the cylinders on each head they have a hex head for removal.


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