Mercruiser Overheating (so am I)
03-27-2019 | 03:17 PM
#21
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03-27-2019 | 03:22 PM
#22
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This may be a long shot but my neighbor had the same issue with his alpha set up, it ended up being a plastic tube that is inside the outdrive it melted and bent in the middle you couldn't tell until it was removed other than that Id look at corrosion where the hose comes off of the transom assembly they can corrode shut over time. You may want to remove the inlet hose coming off the drive to make sure the impeller is pumping water it may help you find the issue also be careful running it without water going into the drive the impellers can burn up quick. Wish you luck hope you figure it out
03-27-2019 | 04:16 PM
#23
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From: KY
Didn't think about that when posting, but you can still swap the drives for testing. Not going to hurt anything, just don't do it for days. You will need to swap the cable movements or just use F for R and vise versa. The top rotation remains the same and all shifting is done in the lower section
03-27-2019 | 06:21 PM
#27
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When you replaced the impeller was there any chunks missing? They can make it into the motor if they come apart depending where the oil cooler is located i had over heating in one of my risers before because a piece of the impeller was stuck behind one of the ball check valves on the thermostat. I'd start pulling all cooling hoses and looking for issues, also try taking the block drains out if you can and maybe pulling the risers off (you'll need new gaskets though). Is this a through transom exhaust or through hull?
03-27-2019 | 07:30 PM
#28
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From: Minnesota
Install a clear hose per the bulletin and install a second one in place of the hose hose that goes from the thermostat housing to the exhaust elbow, Run the engine and check for bubbles and flow.
03-27-2019 | 07:32 PM
#29
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JUST TO RECAP GUYS (as a lot of questions and referrals are about things I've already addressed)
"...risers getting very hot, very quickly". "...impeller is good as new". ".. replaced the 160 stat and gaskets!. "...replaced both risers with new". "...removed circulation pump and checked (OK)" "...removed and checked PS cooler (OK)". "...replaced exhaust flappers". I have now narrowed the problem down to being OUTSIDE the boat (leg). No water coming in the boat. I rigged up a hose direct to the thermo housing inlet from the leg and the engine runs fine, risers warm/cool and engine running at around 165-170 constant.
"...risers getting very hot, very quickly". "...impeller is good as new". ".. replaced the 160 stat and gaskets!. "...replaced both risers with new". "...removed circulation pump and checked (OK)" "...removed and checked PS cooler (OK)". "...replaced exhaust flappers". I have now narrowed the problem down to being OUTSIDE the boat (leg). No water coming in the boat. I rigged up a hose direct to the thermo housing inlet from the leg and the engine runs fine, risers warm/cool and engine running at around 165-170 constant.
03-28-2019 | 04:44 AM
#30
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When you replaced the impeller was there any chunks missing? They can make it into the motor if they come apart depending where the oil cooler is located i had over heating in one of my risers before because a piece of the impeller was stuck behind one of the ball check valves on the thermostat. I'd start pulling all cooling hoses and looking for issues, also try taking the block drains out if you can and maybe pulling the risers off (you'll need new gaskets though). Is this a through transom exhaust or through hull?
