Seized 15HP Yamaha 2 stroke outboard

[bobcc]

Start of season - engine out of storage - won't turn over.<br />How do I free it up? <br /><br />I have taken off the pull cord mechanism to reveal a single large nut beneath. I can loosen this, but that doesn't appear to help any.<br />Engine was put away last August with 5ml of outboard engine oil in each plug hole (as usual).<br />This did happen last year, but I was able to turn it by just slowly pulling on the cord until it slowly started to move. It then freed up and started normally. Not so this time.<br />I am in a somewhat remote location with little access to a wide range of tools.

 

[jim dozier]

Re: Seized 15HP Yamaha 2 stroke outboard

If you stored it with the oil in the cylinders it may be a hydro lock (actually a petro lock) due to the incompressibility of the oil in the cylinders. Try taking out the spark plugs and see if it is still locked up. If you loosened the flywheel nut you need to retorque it to the proper specs or the flywheel will come loose. The nuts usually have a fairly high torque.<br /><br />If its still locked up after removing the plugs and it has happened before you may need to take the engine apart. You may have a water leak that is causing rust. An outboard shouldn't freeze up in one season especially if you put oil in the cylinders.

 

[bobcc]

Re: Seized 15HP Yamaha 2 stroke outboard

It was only 5ml per cylinder, which is what I have done for a number of years, so I am doubtful about the hydro lock - but I will give it a try tomorrow.<br />I don't have access to a torque wrench, what happens if I overtighten the flywheel nut a little?

 

[rodbolt]

Re: Seized 15HP Yamaha 2 stroke outboard

use the torque wrench. do it right. I have actually seen the drive shaft tube corrode and lock the drive shaft while sitting. remove the gearcase and try again. that will determine what part is locked up. lower or powerhead.

 

[bobcc]

Re: Seized 15HP Yamaha 2 stroke outboard

OK. It's a trip to the mainland I think. I haven't the tools to hand to do this here. Thanks for the advice.

 

[bobcc]

Re: Seized 15HP Yamaha 2 stroke outboard

I see I can't close this topic myself. It would be a useful function if the person who posts the original topic could also close it (or have I missed something).