05 knocking

[allanb55]

Hello I am a newbe, I have a 15hp 4stoke short shaft tiller merc, it is on a 15 smokercraft boat. I just finished the recomended breakin period, and I am getting a kocking noise a full throttle. At first I thought it was internal but after watching the motor rock from side to side I ruled that out. It only kocks a full throttle and when it is on plane. any help would be nice I just do not want to take it back to the dealer if it is something simple thanks again.

 

[papa_Lazerous]

Re: 05 knocking

if it is knocking then take it back!<br /><br />better to look a little stupid if it is somthing simple than trash a new motor. Its hard to tell what it could be just by you saying knocking. A trained ear will have a much better idea when they hear it

 

[Trophy23]

Re: 05 knocking

Ditto John_Evinrude. And let us know what they find. I have same year and hp in Big Foot model and would like to know if it's something I should watch for too.

 

[allanb55]

Re: 05 knocking

it is on its way back to the dealere I will let you konw thanks for the advise

 

[allanb55]

Re: 05 knocking

The pitch on the prop was too low so the motor was hitting the rev limiter and cuting out, It just sounded like knocking. got a different prop and all is well

 

[AMD Rules]

Re: 05 knocking

Thats too bad... a perfect example of a good time to buy a bigger boat and explain to your spouse that it was the only solution available to you that would lower the motor rpm!

 

[Dhadley]

Re: 05 knocking

AMD -- thats good!

 

[Jeff Salinas]

Re: 05 knocking

Hello all,

3 years later I would like to add to this thread. I just recently bought the exact same motor; a used 15hp Mercury 2005 model. It's on a 11' tunnel hull inflatable. When the motor is opened all the way up you can clearly hear a knocking noise from the motor. I would like to know the different prop pitch size it was changed out to in order to stop the knocking.

Thank you,

Jeff