01 Yamaha 50TLRZ 50hp 2-cycle bad compression

Hello all. Glad to have found this forum.

All three of my cylinders are reading 60 psi in compression. The head gasket looks pretty deteriated from an external view, but not sure if that is relevant. The motor was used mabye only once every year or every two years sadly. Lots of carb cleaning has been done.

It ran decent last week. It would jump on plane with a fast start, but a slow start would kill it.

I ran out of gas in the bay, though. I refilled and ran about 1/2 - 3/4 mile back to the ramp possibly without any oil in the resevoir. Not good, I know. I was just fed up.

It ran ok in the garage after that. I ran it and sprayed carb cleaner into the carbs to clean them out some more.

Then it stopped starting up for me. It will only now start and run with carb cleaner sprayed in it.

Guessing it burned up.

I have ordered a borescope to take a look inside the cylinders...although I'll be an amatuer at figuring out what I'm looking at.

Curious if there is a decent chance that just a head cover gasket and cylinder head cover gasket replacement will get it back up to compression.

Any ideas are appreciated.

Pull the cylinder head off now.

I would throw a table spoon full of oil in each cylinder and retest.

Motor hot. Battery fully charged. Known good gauge. Throttles wide open. Crank until the compression stops rising.

Strange that the motor would run out of gasoline at the same time that the oil tank is getting low on oil.

Thank y'all both. Here's where I am now.

I started with removing the head, and of course, a few of the 14 bolts were rusted and stuck. I'll have to learn next any tips on how to drill them out before going forward. One is at the bottom and semi-blocked by part of the lower cowling.

Head is off. Trying to upload pictures of the cylinders and head.

Middle piston is missing a big old chunk.

Oh well...

Put piston on #1 to bottom of stroke.-----Post pictures of cylinder wall both sides.----Repeat with other 2 cylinders.

The second and third picture clearly indicate piston / ring problems.----Motor has to come apart.

Thank you.

I'm shopping for a used one.

So far they are hard to come by.

All depends on your location.----Salt water areas means used motor are scarce.-----Areas with lots of poor folks and used motors are scarce.----Freshwater areas with lots of rich folks and used motors may be plentiful.----Your location ?

I'm near Austin Texas.

Any good source for looking at motor weights?

I'm looking for the difference in my 2-cycle 50 hp and a 4-stroke 60 hp.