2001 Yamaha VMAX HPDI making awful clunking noise

Ranger15001

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Apr 23, 2019
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Just purchased a 2001 Ranger with a 150 Yamaha vmax hpdi with 22 hours on it from a private party. We took the boat out to test drive and everything ran great, it did about 50mph, which we predicted it would. Still, we wanted to make sure it was okay, so we took it in to our local Yamaha dealer/shop to get the engine looked over to make sure everything was as it should be. Once we got it back, the motor lost its “edge”, it had no get up and go and we could only get it to go 38mph. We thought it might be the spark plugs, so we replaced all of them. Took it back out on the water and it ran awesome! Performed how t should and was back up to 50mph! We drove around a bit and opened it back up to get back to the trailer. Half way there the engine started to make a big clunking noise. We **** the motor off right away. We turned it back on and the noise was still there. Have read it could be the lower unit or possibly the power head?
 

rejesterd

Petty Officer 2nd Class
Joined
Sep 20, 2018
Messages
142
Yes, it could be the lower unit or something in the power head.

Is it like a clatter that increases in frequency as you rev up?

I would take the lower unit off, take out the spark plugs, and turn the flywheel by hand. If you don't hear a noise or feel some obstruction when turning it one full revolution, then I would say the problem is the lower unit. I wouldn't run the engine any further until you identify the noise, because if there's internal damage, it will just get worse and possibly become catastrophic.
 

Ranger15001

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Apr 23, 2019
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I would describe the noise as a loud clunking/knocking. Does it both in forward gear and at idle(never tried reverse). I did spin the prop by hand and that sounded almost like a little jingle or like sand rubbing on metal. It’s never made that sound before. Could it still possibly be the lower unit even if the knocking persists at idle?
 

scoflaw

Ensign
Joined
Jun 2, 2010
Messages
962
Sure, the drive shaft always turns when the motor is running. Like said, remove the lower and start it up for a short period. Drain your lower unit and look for metal, rotate the drive shaft by hand. This should pinpoint which of the 2 it is.
 

rejesterd

Petty Officer 2nd Class
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Sep 20, 2018
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142
Yeah if the prop is sounding funny, then it's probably best to drain the lower unit and check that out first.
 

Ranger15001

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Apr 23, 2019
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UPDATE: We checked out the lower unit and everything looked okay. So, we brought it to our mechanic and basically we can either rebuild the motor or buy new or used. What ended up happening is, because the previous owners didn’t winterize the boat properly, the injectors clogged which cause the engine to overheat. Which cause a piston shaft to snap in half and the piston itself to melt into a spark plug. The loose piston shaft put gouges into the block. All this happened in a matter of 30 seconds.
 

Ranger15001

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Apr 23, 2019
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Anybody know of good reliable places/websites to buy a used 150 HPDI? I really do like the motor and don’t have the money to buy brand new. And I’ve heard a nice used motor could be cheaper than a rebuild. I would just used the old motor for parts if anything were to happen to the next one, or sell the good parts on the other one for cash.
 

rejesterd

Petty Officer 2nd Class
Joined
Sep 20, 2018
Messages
142
Too bad, but thanks for posting an update.

I would look on Facebook Marketplace.. I think that has now surpassed craigslist and others.
 
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