evinrude 70hp 4 stroke cooling system

bob keen · #1 May 25th, 2008, 07:00 PM

Guys, forgive the question. New at the boating game. Have had the above motor on pontoon several years, never a problem, almost in new condition. stays in the water all year. every spring about this time, I've gone out started it up, cleaned the deck a little and gone out. For some reason this year I looked to be sure the engine was cycling water through it. I don't think I've ever done that, just assumed all was well and it was. No water is coming out of the back. Is this supposed to happen immediately or does the engine have to run for a while before spraying water through the jet? If so, how long? Does a thermostat have to open? I'm afraid to let it run for fear of damaging the engine. If you can help me on this, I'd really appreciate it. I've let it run for up to 5 minutes. Do I need to let it run longer? I've checked the jet to be sure it wasn't plugged by dirt dobbers, etc. It may have done this every year and I just never checked.

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bob keen · #2 May 25th, 2008, 09:04 PM

update. water still not coming out of the jet but i can feel air pulsing out. when i put my finger over the hole to stop the air, bubbles come out from around the prop. also, the air is not coming out very strong. any ideas would be appreciated.

JB · #3 May 25th, 2008, 10:17 PM

On that engine the telltale comes from water pressure before it is circulated through the engine. If there is no stream water is not getting to the engine.

Also, you should get a warning beep if the engine overheats.

You did not say when the impeller was last changed, though it sounds like the water intake is either blocked or getting air instead of water.

Change the impeller and make sure the water intakes are clear and under water.

bob keen · #4 May 26th, 2008, 09:50 AM

Thanks JB. The intakes were definitely underwater, and I looked at the intakes when i had the motor tilted up and they didn't appear blocked. I could see through them. I even ran a wire in and moved it around but really didn't see which direction to go from the two vents. Is what you suggested something I can do or would I have to get it serviced. Thanks again for the response.

bob keen · #5 May 26th, 2008, 09:51 AM

BTW the impeller hasn't been changed.