74 johnson 50 locks up

[willard887]

Ok here it is..... ok i put my 74 50 horse powerhead on a different lower unit today. Engine run fine yesterday, got it together and took it out. Fist i notice exhaust leaking out from under powerhead and water running down front of lower unit. Got it .. I messed my gasket up during install, my question is why did it lock up right after that? engine just locked right up and died. i could see it was pumping water but it was weak, as soon as it locked it started right back up and would run fine then just lock up again. Now if the gasket is messed up and its losing water from reaching the block could this be the culprit? Or could it be gears in lower unit locking up? thanks in advance for help.

 

[willard887]

Re: 74 johnson 50 locks up

no signs of overheating

 

[1946Zephyr]

Re: 74 johnson 50 locks up

Does it lock up instantly, or slowly? If it does it again, quickly see if you can turn it by hand, either direction. If it feels stuck, then I would say that it's over heating and the pistons are seizing up in the cylinders. If it locks up instantly, like someone threw a wrench in it, then I would say there is a loose rod bolt.

 

[willard887]

Re: 74 johnson 50 locks up

The first lock up was slow like it ran out of gas. The next time it was pretty abrupt, and this only happened when i started putting the engine under a load. The engine run like a top before the swap but i know that doesnt mean much. I thought maybe it was lower unit gears locking up since it never did it in nuetral. But im going to try a new powerhead gasket and install a water pump tattle tell so i can really see the water pump flow

 

[willard887]

Re: 74 johnson 50 locks up

ok got a new gasket put it back together now it runs like a raped ape. It used to have the big gearcase lower unit whitch gave it no power i put it on an 1983 model evinrude with the small gearcase and wow what a difference. and yes the engine was getting hot very low water flow with bad gasket thats why it was locking up

 

[Cap'n Chaos]

Re: 74 johnson 50 locks up

Thank you for posting the resolution.