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RSRBOB, Technician
Category: Boat
Satisfied Customers: 1078
Experience:  Former Yamaha Factory Service Rep, Dlr Line Tech, Serv Mgr, G/M
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We have a 2002 FX 140 Waverunner Jet ski. Some water got

Customer Question

We have a 2002 FX 140 Waverunner Jet ski. Some water got into the engine compartment when it was left in the water for a day or two. It did NOT go over the top of the engine or get any water on the air cleaner, etc.
After pulling the jetski out of the water, we drained the water and rinsed it well with fresh water. We drained that and replaced the engine oil and filter.
The motor was working fine before that incident. It has not wanted to start after that.
We checked spark, and it's good. We hope we have the firing order is right after plugging and replugging the wires.
We have tried spraying starting fluid, and it seems like it wants to start, but just won't quite get there. Any ideas? Sounds like timing is off for some reason.
Submitted: 1 year ago.
Category: Boat
Expert:  RSRBOB replied 1 year ago.

HI and thank you for your question.

As it sounds like you suspect, the timing should not be affected by water in the bilge (engine area). However, since you mention something that makes you wonder about having the spark plug leads connected to the correct plugs so you have the right firing order, I will address that because it is a good possibility.

The good news is, you only have 2 coils. That means that cylinders 1 and 4 fire together and cylinders 2 and 3 fire together. Typically the spark plug wires are cut to length and often times you can get a good idea of what lead goes to which coil based on that. The closest cylinder to the electric box should have the shortest lead and each successive lead should get progressively longer going to each next cylinder. So cylinders 1 and 4 should have both the shortest and longest leads, and cylinders 2 and three should be the 2 mid length leads. It does not matter which lead goes to 2 and which goes to 3 because they both spark at the same time, every revolution, even though it is on combustion stroke every other revolution. The second spark is just a wasted spark that happens on the exhaust stroke of the 4 stroke cycle. Remember that pistons 1 and 4 are at top dead center at the same time and cylinders 2 and 3 are at bottom dead center. 1&4 and 2&3 as pairs are always 180 degrees opposite of each other. So your firing order is 1, 2, 4, 3.

I would take a close look at the plugs for presence of water on the spark plugs too. Either the engine got water in it, or there is water in the fuel, either of which will prevent the engine from running. To check for water in the plugs, take them out, hold one by the terminal end and sharply tap the tip end on the palm of your other hand to see if water droplets come out of it.

While you are at it, make sure the air filter element has not gotten wet too. If it has, it will need to be replaced.

Let me know what you find and if you need further help, we can go from there.



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