Yamaha 30D 3 Cylinder "locked"

[almetelo]

Hi!

I do have 1995 Yamaha 30DMO 3 cylinder outboard which always worked great and never had problems, just had to clean carbs twice times to times because water on gas. Engine have been stopped the last 3 years.The only care I had was flushing and some TCW-3 oil on cylinders. Now to start the engine I had to clean cabs and after that was fine again but for a short time, dont even went to the sea. The engine have been 2 weeks stoped and after that the engine was “locked” which didn´t happen in 3 years stoped. Just the lower cylinder was “locked” but I could move the engine with a wrench on the “wheel” and unlock it. I thought it was some water from cooling/exaust sistem to the lower cylinder by the gasket but it wasn´t, its was perfect. Then I didnt run the engine again and then after a couple of weeks is locked again. If I unlock the engine after a few weeks is locked again and just the lower cylinder. I didn’t reassembly the engine again.
Some ideas?

[robert graham]

Maybe remove 3 spark plugs and turn motor with flywheel nut on top to see if any water, gas/oil may be in cylinders? Look in sparkplug holes with flashlight. If water is in cylinders then iron piston rings can quickly stick to steel cylinder liners with rust/corrosion. May have a bad cylinder head gasket or pin hole in water jacket. good Luck!

[almetelo]

Hi!

I’ve found the problem of motor “locked”!

Last week my 30D was completely “locked” not even with a wrench on the flywheel I could move the cylinders this time. So I had to put my hands at work…
Like Graham sugested I inspected the 3 cylinder by spark plugs and no signs of rust/corrosion or water like I previously have seen when I dismounted the exaut, so thought that could be the crankshaft or the bearing because I couldn’t see any other reason at first sign (let me say that my knowledge of mechanics is weak)

So I removed the motor head off and found that was good, now all 3 cylinders could move really easy.

The problem was on lower casing and the gear was full of water instead os SAE90 gear oil! I guess it must be all rusty! Tomorrow I’ll find a dealer because I need a special tool to remove the nut!

Maybe I’ll post so fotos.

Thanks!

[robert graham]

Maybe you can find a good used or rebuilt lower unit to just bolt on there. If your lower unit is corroded up enough to be "locked", it could be expensive for all parts and labor to repair....but you can check it out! If you're in saltwater then corrosion would be much worse! Good Luck!

[almetelo]

Hi

Bought a "new" (for me) used lower casing by 100€ which is cheaper than fix the older one.
The appearance is worst but don't leak.

Yamaha 30D 30DMO 2 Stroke 3 Cylinder 30 HP Outboard Tiller Autolube 1995 6J8 - YouTube