outboard making a gurling noise while underway

[djohnson52]

On my way back in today I noticed a couple issues coming from my port motor( 2001 Yamaha 150 hpdi). two or three different times the rpm's jumped a little (couple hundred rpm's) but I was able to adjust the throttle and it responded accordingly and then operated normally the rest of the way in to the marina. I was moving at around 2200-2300 rpm due to conditions and heavy boat traffic when this occurred. As I got close to the marina I was gong slow again, probably about 2200 rpms and I could hear a gurgling sound which I think was coming from my port motor, but I could not decipher which one it was for sure. The boat still accelerated as it normally does and cruised well on the way in, but I had never heard this gurgling sound before.

The conditions on the way in were sloppy, wind was 10-15 knots( wind and current in opposite directions) with gusts up to 20-25 and 2-4 foot seas. My wife and two little kids were sleeping in the cabin forcing the bow down more than normal. Not sure if this matters, but I recently added startron fuel stabilizer and yamaha ring free 2 weeks ago. I have used the boat twice since adding the fuel additives and it ran without issues those other times. Could this just be simply because of the sea and wind conditions and added weight in the bow? What about a fuel and/or air mixture issue?

I should also note that the port motor does need a throttle cable adjustment as it is slightly off from the starboard. The port motor control is slightly ahead of the starboard control while running at the same rpm.

Any opinions or advice would be greatly appreciated. Thanks!

 

[VeroWing]

From the facts you are providing, slightly rough seas, more weight than usual towards bow, and steeper winds, you may have needed to tuck your outdrives down in the water further than you usually do to keep them from cavitating and raising rpms. being that throttles are not even, the one running the higher rpm would probably break loose first. this is just an educated guess, and it could be something completely different.

 

[djohnson52]

VeroWing,

Thanks for the input. I believe you are correct. I spoke with a buddy of mine today and he basically mentioned the same thing, mentioned something about ventilation as well. I think my issue was I was going too slow for the conditons, especially with the added weight in the bow and the water was back filling and was forced out by the engine revving higher. I think my engines were trimmed up slightly as well like you mentioned and the motor that revved high was the port motor which needs the throttle adjustment.

I hope that is the answer. Thanks for your help.