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93 Yamaha 55hp outboard losing power upon acceleration and dying

J

jrwitte37

New member
Originally my motor would struggle to start and take a bunch of tries and choking etc to start up, but when it started up it would run fine. I just replaced the spark plugs, got new fuel and added some seafoam as well for good measure, and it started up quicker and ran fine to the fishing spot, but when i went to head back to the dock, it started up then slowed then power after accelerating. I am thinking i have to dig into the carbs maybe? any suggestions?
 
jrwitte37 said:
Originally my motor would struggle to start and take a bunch of tries and choking etc to start up, but when it started up it would run fine. I just replaced the spark plugs, got new fuel and added some seafoam as well for good measure, and it started up quicker and ran fine to the fishing spot, but when i went to head back to the dock, it started up then slowed then power after accelerating. I am thinking i have to dig into the carbs maybe? any suggestions?
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slowed, then lost power** it continuously would start up and i could run it low RPM but when i went to accelerate much at all it would hardly let me or would sputter out
 
Sounds like a fuel delivery problem. I've seen a needle valve in a carb get clogged where only a small amount of fuel would pass the debris so the engine would run at low speed but die as the fuel in the float bowl got consumed. The same thing could happen with a clogged fuel filter that is only allowing a small amount of flow.
 
I have a 2008 50 hp Yamaha it crankes fine in the yard but when I put it in the water it will crank and shut right off won’t take any trolly just shuts down what is the problem
 
You changed the spark plugs. You need to double/triple-check the plugs. My friend had the exact same issues with an Evinrude 100 a few years back. He just bought the boat, owner had the documentation for a recent engine service/overhaul, apparently they had a lot of work done to it. I was with him on the shakedown trip and noticed the odd style of plugs. He found a local mechanic who immediately replaced them saying they were the wrong type and the motor fired right up and ran beautifully when we took it out.

From what you've told us, the plugs are the only thing that's significantly changed, so I would start there.
Mike
 
I should also mention that we ran my friends motor in the yard first and no issues detected. We got back from our lake trip, hooked up the muffs, no issues. Sounds eerily familiar...
 
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