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1988 Mercury 45hp Pro Fifty Overheating issues - Pictures, story and videos included.
Lets start from the start. I bought a 1976 Boston Whaler with a 1988 Mercury 45hp, Pro Fifty model, 2 stroke and 4 cylinders. It didn't start right away but after a little tinkering it started and ran great. I took it out on the lake for a test and it idled great, started fine, and was pretty quick! After 40 seconds of running though I got a overheat alarm. As soon as you slow down and get the boat off a plane the alarm goes away. I then brought the boat home and put in a new thermostat, wear plate and the 2 gaskets that go above/below the plate. Then I took the boat out for another test but unfortunately I had the same overheat alarm.
Fast forward to today. I did a compression test and had (from top to bottom) 123, 128, 128 and 120. Then I took the videos you see below which may show my issue. I removed the lower unit and back flushed the engine with water from the hose from the top of the block through the water tube. After doing that a little I plugged the water tube, and tried to fill the block with vinegar in hopes of breaking up any salt deposits that might be in there. Most of it came out the exhaust and im not sure how effective it actually was. Then I back flushed again, then flushed from the water tube back out the tell tale hole. I will do this again tomorrow with an air compressor after I buy one.
It looks like the issue may have been with my impeller install as I dont remember water shooting out the top of the LU like that and it looks like I have some sort of exhaust leak. I posted pictures of most of the seals and I was hoping you guys could point out which ones are wrong.
Video 1:
Might be the source of my issue. I didn't notice this before because I was running the boat in a barrel and then in the ocean. Water flowing out from where the lower unit mates up to the mid section. How does this even happen? Where is it leaking from/pressurizing the midsection?
Shows the stream building when the engine revs, then a close up of spray leak #1 which I am assuming is fuel because of the way it pulses. Maybe this explains why it doesn't seem to idle as well as it used to and stalls. Then, I go to the other side where you can see fuel (i assume) leaking from the carbs. Can't tell where it is coming from. When I prime the fuel bulb fuel will shoot out of the bottom carb once I build pressure. Maybe related? Then the engine dies at idle.
Video 3:
Looks like I have an exhaust leak or something as this gunk is leaking out of the area where the lower unit meets up with the mid section. Short video but if you pause it you can see what I am talking about. What's the deal here?
Is this seal in the right place(question 1)?
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040245_zpsd3aff999.jpg
How about these (question 2)?
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040246_zps8fb0b8ab.jpg
Running vinegar through the block
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040250_zps693fcfc5.jpg
I assume this is for the oil mix
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040251_zpsb68faee0.jpg
Found this in the bottom of the cowling
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040254_zps4eb279aa.jpg
?? Interesting work
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040255_zps660098c0.jpg
More random wires to no where
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040256_zps3bc79612.jpg
Pointer finger on yet another wire to nothing
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040257_zpsc76178c5.jpg
What is this thing tapping into cyl #1(question 3)?
http://i50.photobucket.com/albums/f320/blueovalstanggt/2013/Mercury%2045/P1040258_zpsd512f327.jpg
Thank you in advance for all the help. Once thing I really enjoy about this motor is I am learning a lot. My previous experience was limited to automotive engines. Thanks again.
Edited by Keven on 05/22/13 - 9:39 PM
1981 15' Custom powered by 2005 Yamaha F60
