1978 M900 Seized up

[Mark_Taylor]

I recently bought a 1978 Ray Craft boat with a Mercury M900 (90 hp) on the back. The boat itself looks like it's in great shape. Had to replace the steering cable no problem. Well I opened up the motor and the motor looks like it's in great condition. I did notice a few of the wires on the wiring harness tha needed to be replaced so got that taken care of. Then I noticed the flywheel isn't budging what so ever! I've tried putting diesel in there. It did drain through and out the bottom like everyone said it should. Still no movement in the flywheel. I've considered putting some brake fluid in there and letting it sit. But I wanted to know what else I need to look at? Am I missing something?

 

[flyingscott]

Take the lower unit off that might be whats seized.

 

[Mark_Taylor]

Alright. If that's the case what am I looking at having to do to repair? Never really dug this deep into one but am enjoying the project that's why I'm trying to learn

 

[flyingscott]

Won't know until you know for sure what is seized. If the lower unit is seized that tight it will be cheaper to find a replacement. If the powerhead is seized it will be more than likely be cheaper to replace the motor. They are more pricey to rebuild because od the blind-bore design and the tools needed.

 

[Mark_Taylor]

Thanks for the advice. I did find a replacement motor if needed. I'm hoping not have to replace it but if it gets me on the water then it is what it is!