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Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I have a 2004 SX230 Yamaha boat. My boat was being held in a

Customer Question

I have a 2004 SX230 Yamaha boat. My boat was being held in a divorce settlement and it sat for 3 years. when I winterized the boat before my ex and I separated I filled the tank with gas and put fuel stabilizer in the tank. I cant remember if I ran the engines with the stabilizer in it though. I sprayed fogging oil in it at the time and again when I got it back. The boat is up for sale and the buyer would like me to take him out on the water. I replaced the battery, put about 7 gal of fresh fuel and removed the plugs and cleaned them and put them back in the engine. The engine turns over but it will not start. What can I do myself to get the engine started? I pulled the plugs again after it would not start and smelled the plugs. They have a chemical smell to them, not a fuel smell.
Submitted: 3 months ago.
Category: Boat
Expert:  RSRBOB replied 3 months ago.

Hi and thank you for your question.

You mentioned fogging the engine and putting 7 gals of fresh fuel in the tank.

First, exactly what procedure did you use to fog the engine?

2nd, if you filled the gas tank when you put it up the last time, how did you put 7 more gallons of fuel in it?

The reason I ask that is if the tank is not completely full, there is air space above the fuel level and allows for condensation, which eventually leads to water in the gas. I am also curious as to what the existing old fuel smelled like when you added the new fuel?

I would also suggest checking the spark plugs to make sure they haven't fouled on you. Fouling occurs when the porcelain insulator becomes saturated with oil that makes it a conductor, not an insulator. Therefore, the spark will jump from the insulator to the shell of the spark plug and will not fire under compression. To test this, pull the spark plugs out, put them back in the spark plug caps and lay them on the valve cover, but away from the open spark plug holes. Crank the engine over and observe the spark. It should be a fat blue spark jumping across the gap between the center and side electrodes. If it is white looking spark, or orange, and appears to be jumping around and looking more like a sparkler from the 4th of July than a fat blue consistent spark, the plugs are fouled. There is no cleaning a fouled spark plug. It needs to be replaced.

Let me know about those things, and we can go from there.


Customer: replied 3 months ago.
I am replacing the plugs tomorrow. The fogging oil was purchased from the local motor sports shop I bought all of my boat supplies in Lake Havasu AZ. I followed the instructions in the Yamaha boat manual. I did not smell the fuel prior to me adding the additional fuel. Is it possible to use engine starter spray in the spark plug holes to get the engine to fire up? Once i get the new plugs in the boat I will make another attempt to start the boat. I will send you a message with the results
Expert:  RSRBOB replied 3 months ago.

Thank you for the additional information.

My concern is you did not say you started the engines while fogging it. If you were just spraying oil for 3 seconds in the spark plug holes without running the engine, it is going to pool up on top of the pistons. If that is the case, you should leave the spark plugs out and crank it over to make sure as much oil as possible is pumped out of the cylinders.

If the new spark plugs don't do it, you are probably going to have to drain the tank dry and then add fresh fuel.

Let me know how it goes.


Customer: replied 3 months ago.
I fogged the engine when I winterized it 3 years ago and I did it again when it would not start. I did not spray into spark plug holes. I have not tried to use engine starting fluid yet. I am going to pick up new plugs today and try to get it to start without using fluid.
Expert:  RSRBOB replied 3 months ago.

Thank you.

Just trying to get to the bottom of how you winterized it. Did you spray the fogging oil in the intake as the engine was running? I apologize, I mis-read the owner's manual concerning winterizing. The last time you did it, not the 3 years ago, was it running then?

Let me know how it goes with new plugs too! It wouldn't hurt from an educational stand point to compare the appearance of the spark on the old and new spark plugs.



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