Clanking noise near oil cooler (AR230HO)

[Acard7]

As long as there is no play in either shaft of the intermediate bearings they are definitely good. If your boat runs well I’d just continue on and hope for the best. Absolute mystery as to what is causing that odd noise.. I thought maybe it’s a small exhaust leak too but that’s too weird of a sound to be an exhaust leak.

 

[wajetter]

. If your boat runs well I’d just continue on and hope for the best. Absolute mystery as to what is causing that odd noise..

The nose is quite loud and sounds like something is about to really break. I will spend more time on trying to figure it out.
Will also run compression (on warm engine, last test was on cold) and leak down tests to pin point the reason for lower pressure in 1 and 4. For sure, the valve lash is one of the reasons, but less critical as if the lash was too big. In my case, it is small and just results in less power. Something I can fix during winter

 

[Brad_Ct]

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 ?

To tight of valve lash could explain the low compression on that cylinder, unfortunately there is probably a problem with the valve that is allowing it to pull up into head unless someone shimmed them incorrectly before you bought it.

 

[wajetter]

My initial compression measurements on the starboard ( one that is good) were done cold and throttle closed.
Here are measurements on hot and throttle open:
Cyl 1: 157 closed, 172 open
Cyl 2: 152 closed, 168 open
Cyl 3: 158 closed, 169 open
Cyl 4: 163 open, 179 open

Did not measure the problematic port side because I have valve cover off. Will measure valve lash on all valves (3 intake per cylinder, 2 exhaust) and then run compression test on hot and with throttle open.

 

[wajetter]

@Brad_Ct you mentioned the coupler and clattering in this thread: https://jetboaters.net/threads/sx230-resurrection.20148/post-389190
Was the noise close or like the noise mine makes?

 

[Brad_Ct]

@Brad_Ct you mentioned the coupler and clattering in this thread: https://jetboaters.net/threads/sx230-resurrection.20148/post-389190
Was the noise close or like the noise mine makes?

The noise I have is more erratic, I have replaced both intermediate bearing assemblies and shafts, couplings, impellers, wear rings, and impeller bearings and still have a clanking noise. If you rotate the output coupler on the engine I have play in the reduction unit that I have concluded is what is causing the noise. The noise from your port engine sounds very consistent meaning it is per every rotation of the engine.

I would get your valves adjusted correctly and go from there.

 

[wajetter]

When I grab the coupling assembly and rotate it slightly back and worth, I get the click in the reduction gear assembly, both engines. The clicks are similar in sounds.

 

[Brad_Ct]

When I grab the coupling assembly and rotate it slightly back and worth, I get the click in the reduction gear assembly, both engines. The clicks are similar in sounds.

Ours does the same thing, I just replaced the port engine and had to transfer the rear housing, gear reduction, and oil pump from the old engine to the new one. I inspected all the internals and didn’t price anything that seemed to be worn so I’m assuming the play is normal. I have another assembly in my shed I can take a picture of if you want to see what it looks inside.

 

[wajetter]

Measured valve lash. Here are my doodles

 

[Brad_Ct]

So cylinder 1 has two intake and both exhaust valves that are to tight

 

[wajetter]

So cylinder 1 has two intake and both exhaust valves that are to tight

Thad explains 116 psi on cyl 1.
Cyl 4 valve slap seems in spec, and doesn’t explain 130 psi there.

 

[wajetter]

I have heard a few videos of Yamaha R1s rods knocking. Sound familiar, gave me an uneasy feeling.
I will perform the rod bearing test. Basically, spin the crankshaft until piston starts going down. Then, take an extension and press on top of the piston. A bad bearing will produce a metal clink, when the space between the rod and the crankshaft is closed. A good bearing will not allow the space.

 

[wajetter]

Update. We have a "winner" - cylinder 4 crankshaft bearing failed the test.
Cyl 4, notice the movement and a thud: IMG_4787
Cyl2, notice no movement: IMG_4785

cc @Brad_Ct

 

[wajetter]

@Brad_Ct any tips pulling the engine out? I plan to take it apart and rebuild.
The plan is to take the crankshaft out, take it to a reputable shop and have them verify it is still round.
Then, slap on new the new crank bearings, prelube, put it together, set timing, add oil, spin a few times by hand and put it back into the boat.

 

[Brad_Ct]

@Brad_Ct any tips pulling the engine out? I plan to take it apart and rebuild.
The plan is to take the crankshaft out, take it to a reputable shop and have them verify it is still round.
Then, slap on new the new crank bearings, prelube, put it together, set timing, add oil, spin a few times by hand and put it back into the boat.

I built this and lift the engine with a chain hoist, you will need to take the engine cover off and pull the boat out from under the engine once it out of the engine bay if you do it this way.

 

[wajetter]

Took a couple hours to disconnect the pipes and wires, then had my son help take it out and onto the bench. Pictures tell a story

 

[wajetter]

A rod nut backed out on cyl 4. That explains a lot

 

[wajetter]

Picture

 

[wajetter]

Burn marks

 

[wajetter]

The crankshaft and the rod both have some scoring.
Are they possible to polish ?
The head is coming out either way