1988 110hp Evinrude won't crank

[fishyfishy18]

I have a 110hp v4 Evinrude

I was running a mild load this weekend and the boat was running fine around 4200 to 4500 RPM . Running for about 30 Minutes I hear a clicking and decided to back off the throttle and shut the engine down I took the hood off and checked for any signs of overheating or unusual smells or smoke. Everything looked fine. I also had good water pressure with the thermostat in good working order. So I decided to continue motoring as I was approaching plane ( around 3500RPM) I hear a loud click and the motor shut off and I lost all power. I took the hood off and the flywheel is stuck. I remove all plugs and all are slightly dry but nothing alarming. I am lost for words I have no idea where to start. There was no excessive heat and or smoke.

I looked at the power head and notice some water on top of power head at the water cover gasket behind the flywheel. Then I noticed the gasket had water leaking out of the water cover gasket.

I am wondering what could be the diagnosis and what happened?
I switched my oil from conventional 2 stoke to a synthetic blend would this have to do with anything?

thank you

 

[emdsapmgr]

Hopefully you will find a just a minor problem. Guess I'd check for the worst outcome first, however-just to eliminate one catastrophic event. Possible that you experienced a high rpm overheat lockup. That's when a piston gets hot enough to swell up. If it gets too hot, it will expand enough to internally lock up in the cylinder-and the entire rotating (crank) assembly. Until the block cools down. This type of overheat is fairly uncommon. A specific cyl can overheat internally, while the powerhead still has cooling water circulating through the powerhead-thus no overheat horn warning. Since impeller is still pumping and the thermostats are still functioning, the powerhead would feel "normal" if you put your hand on it. I'd start checking three things: First: pull the carbs apart and visually check the all 4 main jets in both carbs. There could be a speck of dirt blocking one, causing an extreme lean condition on just one cyl. Running without fuel/oil to a cylinder can cause an internal overheat and an ensuing lockup. Secondly, pull both heads and check the four rubber water diverters by each cylinder. If one of these gets out of position or get restricted by sand, salt weeds, that nearby cylinder could overheat. That could cause the piston swelling issue. Thirdly, pull a bypass cover off the side of the block. Rotate a piston so that you can see the skirt of the piston and the ringsets. Check for carbon buildup around the skirt and ringsets. If cooling oil/fuel can't reach the top ring, (due to carbon buildup on the piston) the piston will overheat without warning. The fact that you have a leak at the gasket for the regulator/rectifier at the top of the block may or may not be related to this incident. The fact that water is leaking that high on the block would seem to indicate that the block was full of water at the time-probably a good/normal thing. Was the engine consuming the new oil from the tank? Did you check it for consumption when you filled the oil tank with the new oil-then ran the engine. (mark the tank then check it's level.) Is the synthetic oil a TCW-3 rated oil? Another thing: check the bottom of the oil tank for water. A remote possiblility, but possibly a fatal one if there is much water in that oil tank.