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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 2009 yamaha 212ss. One motor starts fine but the

Customer Question

I have a 2009 yamaha 212ss. One motor starts fine but the other just turns over. I have checked spark, i replaced a bad fuel pump, and i switched cam sensors with the other engine. Still no luck. Any ideas?
Submitted: 1 year ago.
Category: Boat
Expert:  RSRBOB replied 1 year ago.

Hi and thank you for your question.

I would like some clarification on the symptoms.

You said you checked spark, but then switched the cam sensors. Does that mean the engine that would not start does not have spark?

The 3 basic elements required to make an engine run is we have to have spark at the right time, fuel at the right mixture and sufficient compression. Remove any one of those 3 elements and it will not run.

Right now what I would like to focus on is which one is missing on the engine that won't start.

I am also curious what was wrong with the fuel pump you replaced, and did you replace it with a new one?

Once we are clear on what element is missing, we can diagnose it from there.



Customer: replied 1 year ago.
I only switched the coils, plugs and cam sensor from one engine to the other to determine if they were good. The engine that was running before the swap still runs. As far as the fuel pump goes... I tested the voltage going to the pump while turning over and it was good but no fuel flow. I now have fuel flow with the new pump.. It is brand new. I did tey to turn the motor over without the plugs in and i am getting fuel ( like a fog). Is this normal or should i see actual liquid? Also, i checked the plugs to ground and saw spark but it was not a good blue spark. I even had brand new plugs ( properly gapped , which are now on the motor that is running). What could be the cause of weak spark? Please advise. Thank you in advance.
Expert:  RSRBOB replied 1 year ago.

Thank you for the additional information. I appreciate your efforts to communicate the condition to me. It is critical I understand exactly what you are seeing so we don't waste time chasing dead ends.

A weak ignition system component can cause weak spark.

One thing that isn't making sense to me is the fuel pump failure, which sounds like you accurately diagnosed and repaired, and yet the engine still doesn't run. It is highly unusual to have 2 problems, in your case spark and fuel, at the same time. The rare exception would be if something damaged the components. For the sake of an example and I am not saying this is what happened to your boat, but a lightning strike could wipe out more than one component. Even if that were the case, the odds are minimal it would only affect one engine.

I will consult the service manual and we can move forward with checking the ignition system. I will get back with you later tonight on that.



Expert:  RSRBOB replied 1 year ago.

I have the service manual on your boat now. To be able to test the ignition system, you are going to need a peak reading voltage adapter to go with your digital multimeter. If you are familiar with a digital multi meter, then using a peak reading volt adapter is no big deal. They are also not particularly expensive either, especially when you compare them to most hourly shop rates for repairs. :)

Let me know if you are comfortable with that and when you acquire said equipment and we can move forward with diagnosing the spark issue on your engine.