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Clanking noise near oil cooler (AR230HO)

wajetter

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I have put 20 hours on new-to-me 06 AR230 HO this spring. Both engine happily revved to 10.5K and we topped at 48mph GPS.
Today, on water afte ran hour of cruising, no-wake zone, top speed, etc, the portside engine developed a clank. A day before, I changed sparks plug to ngk and gapped to 0.28-30 as needed.
Pulled the spark plugs, they looked ok. To rule them out, changed the spark plugs to the previous set. Removed the impeller shaft to take that out of the equation, too. Same clanking.

The noise seems to be coming from the oil pump area, the back top of the engine. That gives some hope it is not a rod bearing or something, but may be wishful thinking.
Checked compression on both engines, dry. I did not check compression before this, as I was waiting on an adaptor to my gauge, kind of regret this, to be able to rule out.
Checked oil - good level, doesn't smell like fuel (dillution was a concern, but it smells the same as the good starboard engine's oil).
What could have gone wrong?
Oil pressure loss? I didn't see any alarms.

Portside, counting from helm to the transom:
#1: 116 (ah, oh)
#2: 150
#3: 160
#4: 130

Starboard, counting from helm to the transom:
#1: 162
#2: 165
#3: 175
#4: 152

Videos:
 

Brad_Ct

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Both my engines do that and I believe it is play in the gear reduction assemblies.
 

buckbuck

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That seems to be a bit noisier than my engines but it is hard to tell. Check under the plastic cover to see if the coupling is causing it. However, @Brad_Ct probably has it narrower down.
 

wajetter

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Both my engines do that and I believe it is play in the gear reduction assemblies.
Thanks! Can gear reduction be taken apart and the engine run on its own?
 

Brad_Ct

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The more I listen to your videos and looking at you compression reading and the fact that the noise just started. You may have something else going on, possibly a bad valve.
 

wajetter

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The more I listen to your videos and looking at you compression reading and the fact that the noise just started. You may have something else going on, possibly a bad valve.
The cylinder reading 130 psi is at the back, and the one reading 116 psi is at the front.
I am going to get the stetnoscope and poke around.
It seems that having the engine idle on garden hose is not harmful.
 

wajetter

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How can I read actual oil pressure? There's no gauge, just the light if the pressure drops (haven't seen the light lit up though). Can YDS software show actual pressure?
 

buckbuck

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The oil pressure is very low at idle with these engines. Yamaha changed their oil recommendation from 10w-30 to 10w-40. Many times I have seen the YDS show the switch on but it does not illuminate the dash light. YDS does not show pressure.
 

Attachments

wajetter

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Do 2006 AR230 have automatic overheat shutdown?
 

Acard7

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Man idk, kinda sounds like the impeller shaft coupler is hitting the guard above it or something. You can easily remove the guard to look at the coupler to make sure something isn’t flapping against it.
 

wajetter

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The videos are with impeller shaft completely out. Pure engine noise, plus any couplers, reduction gears or oil pump - at least I am hoping it is not a spun bearing. Though oil looks good, I will drain it from the bolt and will also cut the filter to look at shavings. It will be a challenge cutting the filter without introducing shavings to it.

What Brad_Ct said is worrying me also, though a bad valve is not as bad as a spun bearing. Compression numbers on#1 and#4 aren't good for sure.
Maybe, it could be carbon deposits blocking valves from closing and will be remedied by a simple clean up.
 

Acard7

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So you pulled the pump, that’s different than what I am talking about. The engine coupler attaches to the shaft/coupler that is pressed into the intermediate bearing (which is where the pump shaft slides into that you pulled). Unless you slid the engine forward and pulled the intermediate bearing, you still have things spinning down there.
IMG_2711.jpeg
 

wajetter

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So you pulled the pump, that’s different than what I am talking about. The engine coupler attaches to the shaft/coupler that is pressed into the intermediate bearing (which is where the pump shaft slides into that you pulled). Unless you slid the engine forward and pulled the intermediate bearing, you still have things spinning down there.
View attachment 200651
Thanks! Will get under there tomorrow !
 

wajetter

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Confirmed with stethoscope the noise is not the intermediate bearing (popped the cover and touched the bearing housing).
Took out and apart the oil pump -it looks good.
 

wajetter

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Removed the valve cover and measures valve lash (clearance) while at TDC on compression stroke on cyl 1, the one showing 117 psi of compression.
Clearances are too tight. So, I am looking not at shimming but opposite of that. That’s unusual.
What would be the cause of this ?
 

wajetter

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One more development.
So, I took out the jet pump off the starboard engine as well (the one that has no problem). I was a little surprised to hear more rattle noises from the back of it, too, but no way as severe. When I put a stethoscope to various areas, the place making the rattle is the oil cooler box together with the whole gear reduction box. Checked intermediate bearing - it is quiet. I am guessing that is because there is no load on the coupler and reduction gears, the engine's irregularity in RPM (to some degree) and vibration causes the gear teeth to rattle.
I am beginning to think that while, yes, there are some issues with valve lash, that is not the culprit of the scary noises on port side.
What is possibly happening with the port side gear reduction box is that, but to a worse degree.

Also, according to this diagram, there is a bearing inside or behind the reduction box, too...
 
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