Power trim noise

Hi,
I have a 2006 Yamaha F150 and the the power trim unit is making a strange noise. The only time the noise occurs is when the boat is moving forward and I trim the motor down. I am not good at describing noises but can only say the unit has a completely different tone when I lower the unit while under way. When the boat is not moving the noise is the same as it always has had.

I spoke to my mechanic about it and he did not seem too optimistic about finding the problem since it only occurs when underway. Unfortunately, in the area where we live (Shreveport, LA) we are not blessed with an abundance of good outboard mechanics so I don't have anyone else to take the motor to in order to get another opinion.

Has anyone had this problem, and if so, what was the cause and solution?

Thanks in advance for taking time to reply.

Charlie

Re: Power trim noise

I think that the f150 is one of the finest engines that yamaha has ever built. The only problem that i have seen (other than fuel related) was the counter balance assy making a whining noise. there was no specific recall,but dealers will replace it free if its noisy. Some type of descripition of the trim noise would be helpful. Grinding,growling,gurgling,moaning?As long as it's working properly i wouldn't worry too much about it.Be sure that the fluid is full,and apply lube or antiseize to the top of the trim rams.

Re: Power trim noise

My 1999 Yamaha 90HP makes a strange noise at times but continues to work fine, so I don't worry about it much. It's not a constant noise, and I've always thought it might be caused by some air bubbles in the hydraulic circuits. I've never lost any fluid or added any, but it could be a bit low. Since it's a sealed hydraulic system, I've just never really wanted to open up that fluid fill/bleed bolt. It's sorta like the sealed brake fluid system on a car in that the fluid can be contaminated by opening up the reservoir/fill. I do keep the rams very clean and lubricated so that dryness or deposits on them don't wear or damage the seals. The trim rams do push up on some small, grooved stainless steel plates that a blob of grease might help. Good Luck!