Sorry, I know there are previous similar threads, but no one is posting any solutions that worked. So indulge me in giving it another try in regards to the Ultrex I installed about 4 weeks ago. Here's the complete story: I just replaced my 15 year old Motorguide (which did not vibrate and make noise in the turns until its sad, very last days) with an Ultrex 112 with 52 inch shaft on a 21 foot Skeeter. It is quiet and vibration fee at all speeds going straight including from a dead stop. When going straight at a speed 5-6, if I initiate an abrupt turn either way of greater than about 30 - 45 degrees, I pick up a noise in the unit and a vibration I can feel in my feet that lasts about 3-5 seconds and then goes away once established in the turn. I noticed this on the very first turn on the very first day out with the TM. I haven’t hit anything. The problem is not effected by the depth of the trolling motor. The problem is only noticeable at a speed setting 5-6. It’s relatively quiet and vibration free above and below that speed. Hard to pinpoint where the noise is coming from, but I think somewhere in the middle of the unit possibly in the turning servo housing. Its not a rattle like something is loose, but rather a staccato, regular tapping noise like a quiet machine gun. If I turn very slowly I don’t notice it. If I keep it pegged at full turn at that speed, the noise and vibration persist. It will even happen in spot lock when the unit swings around as in the initial effort to stabilize the boat position. If I raise the motor out of the water (with or without the prop), I do not get the noise or vibration, and it is smooth and quiet. I’m seeing irregular surface marks on the composite shaft from where it has gone through the turning motor housing suggesting stress within the turning motor mechanism that either is due the composite shaft flexing within the housing on the turn or the vibration is otherwise being transmitted up the shaft. I am on the third MK prop without improvement. All the replacement props have a 4/19 manufacturing date. The lower unit prop shaft is not bent. Checked it several times. Honestly, I don't think it is a problem with the lower unit since it is so quiet and vibration free out of the water. It only happens under load. I put a G Force Eliminator nut on it which I think made the situation worse so went back to original nut. Rotated the props 180 degrees as suggested by MK. The prop nut is tight and the washer centered. The shaft holes seem to have been drilled on center on the hub of the prop. However, I have noticed that none of the three props sits flush against the motor housing. There is a difference in the width of the seam between the hub and the motor housing of as much as a sixteenth of an inch from one side to the other. Not sure if that is enough to cause excessive strain on the prop in the turn. I checked for slack in the wires running down through the shaft as recommended by one service center - there was none. With the top cover off I checked for anything loose - nothing loose. Tightened down the foot pedal cables a couple of turns as recommended by another service center - no improvement. Tightened every screw and bolt I can get access to. The skeg was a little off center, so loosened the two small bolts under the prop, adjusted it and retightened. The mount is solid to the level deck of my Skeeter. Even grabbed the composite shaft under water while it was making noise and I did not notice any severe shaking of the shaft itself. Stuffed a rag into the mount to dampen any vibration from the gas cylinder or latch straps and put a little tension on the pull cord in case the cord stop was rattling. All to no end. In all other respects, the TM works just fine, and I love its features. My local service center said he sent a video I made to MK and is still awaiting a reply more than a week later. He doesn’t know what to do except tear everything down since the problem can’t be replicated out of the water. I called MK and asked the MK customer service person to discuss with the service people at MK. Her response was "They said only a few motors have been returned to MK for vibration." Of course she would not agree to just send me a new motor or at least cover the $125 one way shipping cost back to MK for a motor that is just 3 weeks old. Not badmouthing MK or moaning about. Just disappointed in the service response and the warranty and I want my money’s worth.
I agree with all the speculation that under the load of the turn there may be enough flow disruption or strain over the prop to set up a harmonic. But then everyone who cares would be posting this same issue and MK wouldn’t be pretending this is not a common issue. Personally I think the load on the prop in the turn is flexing the 52 inch composite shaft as it runs through the turning motor housing so the gears or turning mechanism is not gripping the shaft consistently until established in the turn. Question is, is this “normal” or can something be done to make it quiet and vibration free in the turn. Wonder if there could still be a problem in the lower unit that aggravates in otherwise normal phenomenon. Honestly I don’t think it effects the fishing except perhaps real shallow. But when something vibrates, inevitably that puts stress on bearings and bushings which may eventually fail. I wish I could get a service center tech (tried three who reviewed the video I made) to say, “I’ve seen that problem and here is what I think will fix it,” before just tearing it apart for a problem that can’t be replicated when the unit is out of the water.
Are you having similar issues? What has worked and what has not? If you want to see the videos and photos I have taken, send me a private message. From just reading the blog I can not get a sense of how common this issue may be. But after spending $3000 for a state of the art TM I am not going to give up. Thanks, Skeeterguy48.
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Originally Posted by skeeterguy48
