whine or whistle 2014 5hp 4stroke

[A7X]

Hi guys! New to the forum long time fisherman, first time boat owner... let me get right to it.. searched but came up with nothing I have a 2015 tracker topper 1436 with a 2014 5hp 4stroke merc... 8pitch prop 5780rpm 16mph on plane loaded with my girlfriend, 8yo daughter and gear... 18 mph by myself backed off the throttle as to not over rev but I'll usually have someone with me... I'm having a high pitched whistle or whine that comes on suddenly at higher rpm and won't go away until I let it idle down to 1300 or so... I tried knocking it into neutral at low rpm just before the whine drops off and the condition remains... this will suddenly come on with no loss of power, no vibration etc... you wouldn't notice a difference other than the noise... it seems to be coming from the rear of the motor " square cover" not the recoil housing or the carb... any insight would be much appreciated... if this is a normal condition I can live with it, if it's an issue I'd like to get it fixed... thank you! here's a link to a video if it works https://www.youtube.com/watch?v=fSC_ZSuHYUE&feature=youtube_gdata_player

 

[A7X]

I should've gotten a vid of it doing this at low idle but I was too busy messing around with it with the cover off... the noise starts in the vid at 24sec but take a listen when I slow down around 1min8sec... thanks again!

 

[A7X]

Anyone? I called my local merc service center... bringing it in the end of next week... should I be running it till then?

 

[Fun Times]

Hi there, welcome to iboats! From here it seems have a sound similar to like when air is moving over a thin piece of metal or material making a high pitched whistle sound.

Have you tried running it with the cowling removed while interrupting air flow at various parts of the engine to see if you can change the sound?

Definitely let the service techs look at it so you have a history of the sound, but from here, it doesn't sound like a reason you can't run it in the mean time. Just don't go from home. Let us know what they find, good luck.

 

[A7X]

Hey! thank you for the response... yeah I tried interrupting airflow with the cowl off, moving choke plate, fingers over silencer, looking for loose parts, pressure on rope pull etc... anything to try to change the pitch or consistency of the sound... I'm not sure it's an air resonance thing... it seems to be coming from the valve cover area I've been working on cars since I was 9 years old but these motors are a bit different... I get the concept, just not the whole setup... I'll get it in to the dealer next week and post what they come up with... I won't leave you guys hanging I know unresolved threads are no good, I'm a member of a few truck forums... thanks again! anymore input is appreciated...