2020 AR240 pump/drive shaft/impeller isssue

[Inthrustwetrust]

Took the boat out for the first time yesterday, (2020 AR 240, about 70 hours on it, salt water, flushed and salt away after every use) and starboard motor took a couple attempts to start, ran it for about 20 minutes and got a overheat warning, I shut the engine down, and waited 30 minutes or so to restart. Clean out ports were good to go. After, the motor would start but at idle after about 5 seconds it would come to a abrupt stop with a noise. Motor seemed to be ok, my instinct was saying it was a drive shaft problem. Limped the boat back and pulled the pump today. No obstructions, but I think I have some issues. I didn’t pull the other pump but the wear ring looks pretty beat up compared to what I can see on the other one. The edges of the impeller feel bent over, like they were running in to tight of a space. I attached some photos, but it looks like the shaft may have sheared where it goes into the “cone” in the back of the pump. Lastly looking at videos of some older boats online it looks like the impeller should could out on the shaft with the pump, but it won’t. Not sure if the newer boats are designed different or mine is just extra broke.

There is also some rubber/plastic debris under the intermediate bearing area in the engine bay, not sure if it’s related but I don’t remember seeing it before I went out.

Another caveat, last year after about 20 hours I found both bolts had backed themselves out of one of the motor mounts on this same side. I am wondering if this caused the engine/shaft to end up out of alignment causing these problems. The dealer was made aware and checked out the motor mount issue last year. The boat is also still under warranty, and I have never sucked anything up in this pump that caused me to have to stop/clear it out.

Pictures for reference.

Last photo is the good side.

 

[PatrickKolby]

Broken drive shaft?

 

[Inthrustwetrust]

Broken drive shaft?

Ya that’s what I’m thinking. Trying to check for other damage

 

[Sean R]

Really sorry to hear about this. I have the same year but a 212 and yes the hole shaft pulls out like the older boats. I am going to check my motor mounts this weekend. Did you have any sign at all before hand? Vibration, eng noise etc...

 

[1WetBoat]

That pattern of what looks like black dust under the coupler is a very good indicator of the rubber dampener in-between the coupler rubbing. The engine side coupler has fingers and fits inside the coupler on the impeller shaft side, the black rubber dampener goes between those fingers. If the engine is misaligned, or if the shaft is misaligned, the "fingers" will cause the rubber dampener to rub excessively. That could have happened prior to the shaft snapping or a direct result of it.

The black chunks i cant tell but they could be from the dampener also. Heck, the intermediate bearing housing also has a rubber surround , did you check that?
You mentioned motor mount bolts backing out before, did you check them again?

Crazy stuff man, sorry to hear you're in this situation.

 

[Inthrustwetrust]

Really sorry to hear about this. I have the same year but a 212 and yes the hole shaft pulls out like the older boats. I am going to check my motor mounts this weekend. Did you have any sign at all before hand? Vibration, eng noise etc...

The motor mount bolts I heard rattling around in the engine bay. The shaft issue, not really. Boat had been sitting in the driveway since the end of October. I started the motor for about 5 seconds last weekend, all seemed fine. I didn’t have the hose hooked up so I didn’t want to run it. It took a couple tries to start at the launch, and seemed to be a little rough, I figured it was just from sitting all winter, I got what get seemed like some cavitation after about 5 minutes running at 5500 rpm, I advanced the throttle it cleared thinking I was fine, looking back it was probably the shaft going, about 5-10 minutes after that is when the overheat warning came on. It seems weird where it broke behind the impeller, if anything I would think it would have went at the impeller where all the torque is or before the impeller. I found another thread on here of someone having the exact same break last year.

 

[Inthrustwetrust]

That pattern of what looks like black dust under the coupler is a very good indicator of the rubber dampener in-between the coupler rubbing. The engine side coupler has fingers and fits inside the coupler on the impeller shaft side, the black rubber dampener goes between those fingers. If the engine is misaligned, or if the shaft is misaligned, the "fingers" will cause the rubber dampener to rub excessively. That could have happened prior to the shaft snapping or a direct result of it.

The black chunks i cant tell but they could be from the dampener also. Heck, the intermediate bearing housing also has a rubber surround , did you check that?
You mentioned motor mount bolts backing out before, did you check them again?

Crazy stuff man, sorry to hear you're in this situation.

Everything visually looks fine from my limited view. I haven’t taken anything apart, I’m a big dude, it ain’t easy to get all way behind the motor

 

[Sean R]

That really sucks I am bummed out for you, hopefully dealer and parts go fast. Keep us up to data.

 

[Inthrustwetrust]

I think I posted a update in a different thread, but indeed, broken drive shaft. From what the dealer told me, Yamaha seemed very intrigued/curious and wanted a lot of pictures/details, but is going to honor the warranty. The dealer can’t get the remaining piece of drive shaft out of the pump/rear bearing area, as I guess there is nothing for them to grab onto to get it out. Seems suspicious, but I have never taken the pump apart, so maybe they are right. Anyway, sounds like I am getting a whole new pump assembly. I am extremely worried that things are going to be on back order, pretty unfortunate, already missed 5 weeks of good Florida boating weather.

 

[ScubaMike]

Ive got a 2016 AR240 that im trying to get the shaft out now. I'm guessing the dealer finally got the rest of the shaft out?? Any idea how?

 

[84rzv500r]

That is a broken drive shaft in the pic... Ive broken 3 of them haven't seen one break there... did the shaft bearings set up in the stator housing?

Mostly they break just aft of the splines in the mid bearing housing ...

 

[Cambo]

Ive broken 3 of them

You broke 3 how many hours did you log to break 3? Your signature says 2004 AR is that the model it broke on? This was very rare and only recently started showing up on the newer model boats.

This original post is old my guess on whats occurring is that the shaft develops a crack allowing the impeller to flop around scarring up the impeller housing before sheering off, look at the rust caused from heat and friction on the stainless steel sleeve. This would possibly be noticeable while flushing the motor you would hear a metal clanking as the impeller hit the housing. Another scenario is the the impeller housings seem to be failing much sooner than before. The stainless steel liner deforms closing the gap on the impeller making contact with it, again you can hear while flushing. This contact could create oscillations to the shaft that cause it to fail you can see a distinct darker burn mark in the picture below. Both of my wear rings failed on my 2017 in 2021 that is a very short life.

 

[84rzv500r]

correct 2004 AR210... and i dont think its an hour kinda thing... funny spot to break... I have not broken any of the OE 22mm shafts with 160 MR-1 HO engines and the new 155mm High pressure pumps, I broke (sheared the splines) 1 20mm OE shaft and 2 SBT (cracked and twisted like seen here) 20mm shafts behind the splines with 135 two strokes. and I twisted off a 20mm SBT shaft with the old low pressure 155mm pumps that failed bearings with a 160 MR-1 HO. I have not seen one fail at the big end like that however it looks like a crack and twist like they do at the small end. These usually crack on a shock load then fail later under load or just shear clean off if it's a hard stop.

I've had them shock load/break three ways:

• having the whole boat out of the water, unloading the pumps and not pulling the throttles back quick enough when the boat comes back down and Bang... or pushing a Jet boat too hard in rough water... water is hard going fast...
• ingest something in the pump at WOT or near WOT and stop the engine
• have a hard bearing failure in the stator housing and stop the engine hard at WOT/near WOT

I only use OEM shafts now... SBT's break to EASY... and I use OE, Japanese or European bearings and seals not Chinese.

this is kinda like a prop strike in an airplane...

oh and we just fixed a yamaha two stroke outboard last week that broke the drive shaft the same way when she clipped the rocks with the prop and skeg... broke the skeg clean off, bent the propshaft and sheared the drive shaft just after the splines... the prop didnt look that bad LOL but she said that she goosed it pretty good to try and get away from the rocks...