1979 Mecury 140hp Major Problem

[Repooe]

to make a long story short , i just bought the boat 2 days ago , droped it in the water today stayed around shore to make sure everything was cool , shifted into gear and out , took it for 3 laps at wot around the lake ran great , came back to pick up rest of people , make it half way around lake at wot when it started to lose power going slower and slower till it cut off, i tried to restart it and all i got was a click tried it 2 more times same thing , then tried it a 4th time ,and i got what sounded like a crank but sounded funny like grind scraping and it only did that for a split second then click so i drifted to someones dock and their she sits

 

[Chris1956]

Re: 1979 Mecury 140hp Major Problem

It sounds like you seized it. Remove the spark plugs and turn the fywheel by hand. If it moves smoothly, use the electric starter to take a compression test. compression should be in the low 100s and all even on all cylinders. if that passes, put a timing light on each plug wire and see if you have spark, while cranking it with the plugs back in.

Post results.

 

[Repooe]

Re: 1979 Mecury 140hp Major Problem

Well the good news is i got it out of the water , and it did seemed to be seized not all the way tho , i manged to turn the prop and move the pistons up and down by hand and force but got them to move then i put some seafoam in the cylinders and let the sit in their to break it the rest of the way , hit the key and she cranked put the spark plugs back in and put the lower unit in a tube of water and she started and smoked of course to burn out the rest of the seafoam only problem now is that , she dosent pee not sure if the water wasent high enough not sure witch vents suck up the water , or if its a bad impeller didnt run it for maybe 10 secs

any ideas what vents suck the water? their is 2 right above the prop . then their is 2 more a little farther up

 

[daveswaves]

Re: 1979 Mecury 140hp Major Problem

Well the good news is i got it out of the water , and it did seemed to be seized not all the way tho , i manged to turn the prop and move the pistons up and down by hand and force but got them to move then i put some seafoam in the cylinders and let the sit in their to break it the rest of the way , hit the key and she cranked put the spark plugs back in and put the lower unit in a tube of water and she started and smoked of course to burn out the rest of the seafoam only problem now is that , she dosent pee not sure if the water wasent high enough not sure witch vents suck up the water , or if its a bad impeller didnt run it for maybe 10 secs

any ideas what vents suck the water? their is 2 right above the prop . then their is 2 more a little farther up

Based on your previous post about how to run it in the driveway to do a quick test and your current failure, seizing then not peeing, it sounds like your water pump failed during your trip around the lake, causing the engine to overheat and ultimately slow down and seize. The sea foam will not have taken care of any physical damage done by the seizing, which you are sure to have . You can evaluate the amount of damage by removing the intake port covers and examining the pistons. The gaskets will break but they are cheap and available. Post what you find, pics would be best, and will help to advise you further.

 

[Repooe]

Re: 1979 Mecury 140hp Major Problem

I dont have a book or anything to take it apart i'm gonna take it to the local boat shop and see what they say i know the guys pretty well so i shouldnt get screwed over and i will let you know whats going on and if i have an fed up motor lol