Super Weird Propulsion Issue Today

[wesrich18]

Okay everyone I need some help diagnosing an issue I had today when we tried to go skiing.

Variables
- Boat = 2017 Yamaha 242 Limited S
-Total passenger = 9
-Seating configuration with (1) skier in the water = (7) in the stern, (1) in the bow.
- Spring tune up completed with new spark plugs and wires
- Fresh full tank of gas from the marina

Issue
- boat was running great out to the area we ski
- When I went to take off the whole boat was shuttering and it seems like major cavitation was occurring and was never able to pick up enough speed to get on plane and get him out of the hole. He’d let go and boat took off without a problem when getting back to him. We tried 3-4 time and no change in result.
- At the time I didn’t think to reshuffle where everyone was but I’m starting to think that having everyone towards the back was the issue but I don’t remember having that issue before.
-on the way back everyone stayed in their same positions and I noticed that every time we got out of a no wake zone as I started to throttle up the boat would have slight cavitation and then be fine once I was on plane. So the same issue only lasted a few moments and not enough to really notice unless you paid attention.

I didn’t think it was possible but by having that much load all in the back could that cause cavitation? could it have been causeing the intakes to be slightly out of the water?

What else could it be to cause an issue at low speed but not high?

 

[FSH 210 Sport]

That could very well be the cause. It would have been beneficial to move people up to the front to see what would have happened. No the intakes were not out of the water.

How are your impellers? Is the clearance between the impellers and the wear ring within spec’s?

 

[wesrich18]

That could very well be the cause. It would have been beneficial to move people up to the front to see what would have happened. No the intakes were not out of the water.

How are your impellers? Is the clearance between the impellers and the wear ring within spec’s?

that’s a really good question. I just bought the boat last year and I haven’t had our service department look at that. I’ll probably ask them to check this week.

 

[wesrich18]

That could very well be the cause. It would have been beneficial to move people up to the front to see what would have happened. No the intakes were not out of the water.

How are your impellers? Is the clearance between the impellers and the wear ring within spec’s?

So I talked to the Yamaha dealer today and they made it sound like since I didn’t have cavitation through the whole rpm range and only when taking off they would be surprised if it was the impellers.

they recommended to start with the clean out plugs and either rebuild those or at least clean/service them.
Any thoughts on that feedback?

 

[Ronnie]

Check that non of the sealant of any between the pump shoe and the hill is missing/has gaps it. I haas the same experience on my Yamaha jet boat years ago. Ended up being missing silicone. Once replaced the boat ran fine, the rev silicone I used failed, the funky acceleration came back. The next time around I used 5200, no problems since according to the guy I sold the boat to over 10 years ago. We connected last year and he told me the boat and sealant were just fine.

 

[wesrich18]

Check that non of the sealant of any between the pump shoe and the hill is missing/has gaps it. I haas the same experience on my Yamaha jet boat years ago. Ended up being missing silicone. Once replaced the boat ran fine, the rev silicone I used failed, the funky acceleration came back. The next time around I used 5200, no problems since according to the guy I sold the boat to over 10 years ago. We connected last year and he told me the boat and sealant were just fine.

Gotcha. Is that right where the pump housing meets the hull?

 

[Ronnie]

Gotcha. Is that right where the pump housing meets the hull?

Yes, you will need to remove the intake grate to get to it.

 

[wesrich18]

Yes, you will need to remove the intake grate to get to it.

Thanks!