Need Advice Troops

[andrew j cox]

Would a 02 yammy 50 4 stroke have a guardian or limp mode type system? I’m brain storming why this motor has no top end power
my diagnosis thus far
2 wet combustion chambers probably means plugs are buggered
Many blocked water passages including the main feed between block n head
I found a corroded steel rod bout 2 inches long in one of the big galleries round the cylinders doubt its spised to be there
The head gasket has delaminated tween the layers I think she was pushing compression into the water system
so I’m guessing she was running hot with two badly firing cyl s, motor is non efi, the over heating must have triggered something I don’t know enough about the Yammys electrics n system, I play with old Chryslers.
What do you all think?

 

[andrew j cox]

The piece of steel wouldn’t be an internal anode?

 

[99yam40]

maybe the remains of what held the anode material, if they had a center wire.

4 stroke 50 should have a RPM reduction mode if overheat is happening.
if you were getting water into the cylinders ,that would keep them from firing/running properly

 

[racerone]

Yes they had internal anodes on some motors.-----Test compression and test spark.

 

[andrew j cox]

There’s no rust on the plugs or the bores, it’s possible water was getting the there, it’s the two middle cylinders so 2 and 3 the head gasket delaminated on these two cyls on the outside not intake side, head gasket coming next week, I still need to clean head n block surfaces before I can reassemble and compression test on the shed floor, the over heating no doubt caused all this I think it will be fine now, Fingers n toes crossed , I worked out swearing at them doesn’t fix them, give me a. 4 cyl Chrysler any day of the week, so simple.