1993 Yamaha WaveRunner III - Sitting for Years, Initial Advice Needed

[Adam E.]

I acquired this 1993 Yamaha WaveRunner III this past weekend in Georgia. The ski (though dirty) looks promising and aesthetically I think with gelcoat correction it will shine up just fine.

This ski has been sitting for at least 10 years (has a 2007 registration decal) and I was told by the man that it stopped working one summer and they just let it sit in the yard. The inside of the engine compartment looks very clean for its age and was definitely a freshwater ski. The ski had no battery and I did not attempt to crank it over. Upon inspection I could find no cracks in the crankcase. The e-box was dismounted from the sidewall which leads me to believe the previous owner expected it to be electrical problems.

Obviously before I tackle the outside I need to know what I'm dealing with. There are a multitude of things I plan on doing including:
-Clean/Rebuild Carb
-Replace fuel lines
-Dump oil fuel and add premix
-New Spark plugs

However, before I can tackle these things I need to make sure I have a healthy engine. I want to verify:
1. Electrical Issues (Spark)
2. Compression

What are the initial steps I should take? Should I coat the cylinder walls first with a protective substance (i.e. WD40)?

Basically I'm looking for someone to walk me through their initial thoughts/steps to verify the aforementioned issues? I want to ensure I handle this situation right.

 

[Lumpy]

If you can roll it over by hand, put a battery in it and try firing it up. Diagnose from there if it won't fire. You need a cranking engine to verify spark and compression.

 

[Adam E.]

Update: The engine turns over by hand. I sprayed some WD40 in the cylinders and tried to fire it up with no success. The MAG cylinder has compression the PTO cylinder I don't feel anything.

I'm thinking the start/stopswitch is bad. Is there a way to crank the motor over just by touching the negative lead to the block?

 

[mbrick]

Have you gotten any further on the Waverunner?

No compression on one side means you probably want to pull the head soon and take a look. Would be a poor coincidence if it got cooked and also had electrical problems at the same time though.

Some no-starter diagnoses:
First check the 10A fuse in the ebox.

Is there a way to crank the motor over just by touching the negative lead to the block?
You can touch a positive lead right to the positive lead on the starter to turn it over. The starter is grounded through the block and to the battery, and the positive side is switched by the starter relay.

You can also try providing power to the switch input (brown wire) on the coil side of the starter relay to see if it closes. The starter relay has black going to ground, and brown coming from the switch.

I've also attached an image of the starter wiring diagram for you to print out. OR grab a copy of the service manual which walks you through the diagnosing steps.