250 Yamaha 4 stroke not looking good

[phatdaddy]

I d start with compression

Maybe put a borescope down in that cylinder

[spareparts]

compression test before you go any further, if that cylinder is low, youve probably got a dropped valve. Amazon bore scope that runs on your phone will show you the extent of teh damage. If its a salt water motor, its not worth fixing. Reman powerhead installed will run around $7000+

[steplift20]

Ok will do that but what if the compression is good? Should all the cylinders be around 110 psi? And if that cylinder is bad than we are screwed I guess. But before that I have to check the compression. One step at a time. Personally I don't like 4 strokes and definitely do not like electric vehicles. Sometimes progress is not good.

[spareparts]

compression should be around 175 depending on the gauge. If its good, take a look with one of those bore scopes, if you dont see any damage, throw plug in it and see how it runs

[steplift20]

Will do spare. When you relocate to New Jersey let me be the first one you tell.

[phatdaddy]

have a friend who has worked on outboards for 30 plus years, he said his dream job is opening a shop in Lake Eufala, Alabama and work on nothing but freshwater Mercury V 6 2 strokes

[steplift20]

Phatdaddy , that's what I have on my wellcraft,a 150 2 stroke Mercury of course and I would love to know like spare and your friend how to work on it. I do know some things but would love yo know all of it. It's really a very simple engine ,just the basics carbs,stator,trigger,switch boxes. Plus the other electrical components I would work with a mechanic just to watch and learn.