2000 Yamaha 50HP bad center cylinder

Sdominick

Cadet
Joined
Aug 18, 2020
Messages
17
Wow! That is a lot of incredibly useful information for this project and future ones. Sorry I took so long to get back, been busy with life, family and breaking down this Yamaha 2000 C50TLRY. I have more pictures. Hard to tell if center is not original. It’s mashed to death. Side came apart with rings. “Straight gas theory” is just a theory but took fuel filter off and fuel hoses, poured into mason jar, barely any color, green. But barely. Center cylinder has no free wall, upper and lower each have 1 free wall. No lubricant in gas cylinders heat up, water can maintain upper and lower but not the center. Heats more rapidly. That’s the Theory, it came to me in a dream.😁
 

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Sdominick

Cadet
Joined
Aug 18, 2020
Messages
17
Have another question. Center intake manifold, looks broken, but when I look for replacement they are the same. What is that. Factory? Same failure? Just a question. Weird looking to me.
 

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Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,920
Sorry but you need to have a different dream :)!! If there was no oil in fuel the other pistons/cylinders would show signs of siezing and scuffing.
What you have is pre-ignition damage.














0
 

Sdominick

Cadet
Joined
Aug 18, 2020
Messages
17
Sorry but you need to have a different dream :)!! If there was no oil in fuel the other pistons/cylinders would show signs of siezing and scuffing.
What you have is pre-ignition damage.














0
Ok, I’ll buy that. What is the cause of pre ignition damage?
 

boscoe99

Lieutenant Commander
Joined
Aug 22, 2013
Messages
1,997
I am still going with detonation damage or pre-ignition damage. One can lead to the other.

The ugly red headed step sisters of catastrophic engine damage.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,089
The 3 cylinders are surrounded by the common water jacket.-----I need to grasp this " free wall " concept as well.-----Please explain !
 
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