Hollow Howling Sound at top speed and while turning right.

maxpipefill

Cadet
Joined
May 28, 2018
Messages
11
Hello,

I usually don't have to create posts, if I look hard enough a million people have had the same issue and recommendations have been made. But, I cant seem to find anything regarding my exact situation.

I have a StarCraft Super Sport 16 foot aluminum with a 1970 Johnson 60hp motor with an aluminum 13.75 x 15 prop, an SE400 Hydrofoil and anti-ventilation plate positioned 1.7 inches above keel.

The boat has manual trim, if I trim the motor 4 holes down from the top on the mount it works well but a little slow (27 Mph)

If I run the motor 3 holes down on the mount it works better (30 Mph) but at the very top of the acceleration in a straight line I hear what can only be described as a faint hollow howl sound , barely noticeable. The same could be said for turning left. But, when I turn to the right the sound is more pronounced, almost sounds like a jet engine.

Ventilation?

My issue is I experience no slipping, no rpm increase, and it doesn't slow down at all.

I guess my question is, Do I have to drop it a notch for the motor's sake and give up some speed, or can I safely run it like this?

Thanks
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
The best manual trim is the one that will achieve for boat to run on plane parallel to water level at speed provided that load is evenly distributed on deck. Neutral trim is usually achieved second/third hole out transom. Outboard (OB) must sit at the sweet transom heigh.

Post a side pic of lower leg for better clarification to show which is the best lower leg height for any OB along some ideas on how to check it and correct it as seems your issue is a badly height setaed OB. Once dialed will forget all about playing with manual trim and OB achieving its full 60 HP output.

Happy Boating
 
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