apollak19

Here are pictures of the coupler. A few things I notice: - rubbing on the inside and outside and cracks - the mechanic is confident that the vibration is coming from this rubbing but not sure what is causing it to rub especially considering it came on all at once and the new coupler is getting the same rubbing - The boat is an 05 and the coupler is from 07, so it was replaced in season 1, 2 or 3 of it's life and has been working fine ever since

Hi there, thanks in advance for reading and help! My 05 Avalanche has now been in the shop for 3+ weeks that the mechanic cannot figure out the root issue so I'm looking to hive mind some ideas/support on a diagnosis. The boat - 05 Avalanche C4 - Black Scorpion - about 400 ish hours What happened - a few hours into our 3rd day of surfing the boat all of the sudden started vibrating. It's mellow at low speeds and gets progressively worse at high speeds. We immediately got it off of the water and into our local shop. The shop replicated the vibrations. They started by checking the engine mounts and alignment and everything looks fine. They took the prop and prop shaft off to make sure they are straight and undamaged and say those are great. They found a bolt had backed out of the coupler so they replaced that bolt. Still vibrating. Next step was to remove the coupler. Turns out the coupler was cracked and has significant wear on one of the inside edges (I will try and get a picture for you). At this time, they ran the engine, tranny and v drive without the coupler and it didn't vibrate. Because of this, we all felt confident that the vibration was coming from the coupler. However, when a new coupler was put on and the prop shaft was connected again, it was still vibrating. The shop says the next step is to remove the v-drive but this may take a long time because they have to lift the engine and they are busy this time of year. They've also never seen an issue like this where the vibes came on all of the sudden and the coupler was cracked but not causing the vibrations. Confidence level is low at this point. I'm writing here wondering if anyone has seen this issue and if you have any idea of what we should be looking at/for. Appreciate any help I can get!

Thanks @Dreamer I'll check that again. It's a new prop as of last year with a handful of days on it and we haven't hit anything but I'll check. Spoke with another shop and they say to focus on the drive shaft, which my mechanic also says is good.

Hi there! Long time listener, first time caller. Your guidance and advice is very much appreciated! I have a new-to-me (late) 05 Centurion Avalanche C4. My family and I have been loving it so far! The dreaded two beeps started just after a few times out on the water for me. I was at my mechanic for something else and had him take a look. The code reader said it was the water pressure. He was familiar with the problem (as are many of you) and recommended a new water pressure sensor. He switched it out, ran the boat on the fake-a-lake and no beeps. Before and after the new water pressure sensor, engine temp has been staying right at and below 175. Brought the boat out and the beeps came back right away. Didn't go away. I unhooked the alarm speaker just for the day and kept my eyes on the temp, still stayed low. Called my mechanic and he said the next step was to change the impeller. The thought is that the impeller is pumping fine just not at the pressure the sensor needs it to stop the beeps. Also, I don't know when the impeller was put in, so it doesn't hurt to change it and know exactly when it was put in. He also says that if this doesn't work, he's got to change the cooler housing. Says that there was a factory defect and an upgraded version came out but it's way passed the recall time. Any other thoughts on what it could be (given the code reader said it was the water pressure)? Could it be something else? Can it be that we just need to reset the comp? I've heard differing opinions and my mechanic says that the codes reset every 5 minutes automatically. A few things to note to help me diagnose the problem: I boat at elevation - around 6.3k I didn't have the beep before the mechanic put in a new Stargazer Perfect Pass - could this have an effect? I didn't have the beep before putting on a new prop - but I assume this shouldn't change anything I had a full ignition tune up done before the beeping started