# Suzuki 9.9 limp mode



## Matt_M (Aug 2, 2021)

Looking for any thoughts on this issue I'm having with my 2011 9.9 4-stroke. The motor is going in limp mode after about 30 seconds on full throttle. I took it to the mechanic and he said he was unable to replicate the problem... $270 dollars later. He said my water pump system looked good, I just replaced within the last year so that make sense. He said when he put the motor in the tank he had to sink it deep so it didn't throw all the water out of the tank. This makes sense because I can run the engine fine at half speed with no issues but once I'm up on plane it gets hot and goes limp. Pulled the boat up on the trailer to keep it in place and gave it full throttle for about 2 minutes, motor was deep enough and didn't go in limp mode. This does not seem like an oil pressure issue because if the intake is deep enough it will run all day on full throttle. Seems like a water pressure issue but my water pump is in good condition with steady/strong water output. Any thoughts?


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## GSSF (May 25, 2013)

Matt_M said:


> Looking for any thoughts on this issue I'm having with my 2011 9.9 4-stroke. The motor is going in limp mode after about 30 seconds on full throttle. I took it to the mechanic and he said he was unable to replicate the problem... $270 dollars later. He said my water pump system looked good, I just replaced within the last year so that make sense. He said when he put the motor in the tank he had to sink it deep so it didn't throw all the water out of the tank. This makes sense because I can run the engine fine at half speed with no issues but once I'm up on plane it gets hot and goes limp. Pulled the boat up on the trailer to keep it in place and gave it full throttle for about 2 minutes, motor was deep enough and didn't go in limp mode. This does not seem like an oil pressure issue because if the intake is deep enough it will run all day on full throttle. Seems like a water pressure issue but my water pump is in good condition with steady/strong water output. Any thoughts?


Could be clogged water jacket. I had a yamaha years ago that did the same thing... the telltale (pee) stream was strong, not hot, and the water pump/housing was new. 

I finally figured it out by using an infared thermometer and shooting the cylinder head. Found the top cylinder to be HOT. Pulled the head and the jacket had scale through it, blocking the entire jacket on the top. It would stay cool enough at low speeds but after about 30 seconds of WOT- buzzer and limp mode.

Good luck


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## lemaymiami (Feb 9, 2007)

One other possibility... I'm betting that like most small motors you don't have a water pressure gauge at all - so you really don't know if your motor is actually getting water when you're up on plane and running (that would account for the exact symptoms you're faced with...). This kind if issue would never be found with a static test (in a tank or on the trailer...). Bring a second guy and make a trip to your waters, paying close attention to exactly where that motor is in relation to the water - at idle, at half throttle, then at full throttle (and have your observer make a pencil mark on the transom water line at each throttle setting...). I suspect you'll find that your motor simply needs to be lower and that just might solve your problem... If that turns out to be what's happening, only move that motor one notch at a time - then test without that observer to see if that cures the problem (striking the right balance between a good running motor - and actually having it deep enough in the water so that your cooling system can operate properly... takes some work since you also don't want it sitting too deep on that hull either.. )

Remember to also account for weight distribution (whatever hull you're running will sit differently with two bodies in the stern than it will with weight better distributed... Hope this helps - and "Aren't boats fun?"

If this isn't your problem then good luck with opening it up to find out whether your cooling passages are obstructed... That's not something I'd want to mess with at all...


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