Overheating damage?

[Bob Bedinger]

2003 50hp Johnson sucked mud ,overheated badly, cleared to steam and then to normal telltale flow-- idled fine. Without ever turning off engine, on attempt to come up on plane,the motor stuttered and would not reach an adequate rpm. Idled home 30 mins with all attempts to increase rpms resulting in same limitation.
Spark pluggs wiring and powerhead all "look" ok.
Haven't been able to sea trial again to see if turning off ignition made any difference.
Was this the overheating protection rpm limiter? Does turning off the ignition reset it? Or is it more likely that I've blown a head gasket or caused other damage. What tests, what remedy(s)?

 

[WillyBWright]

Re: Overheating damage?

All of the above are distinct possibilities. I'd advise a compression check before hitting the water again. but hopefully it's just a matter of resetting the system by turning the key off. If the compression readings look bad, remove the head. Hopefully it's no more than a baked head gasket.