1980 120hp

wvmedic

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I just bought another Starcraft I/O 1980 2.5l 120. I've looking for engine parts and looks like a lot of the hard parts are unavailable, like timing gears and such. I probably should have done that before buying it. Are the internals in fact unavailable, say I want to do a rebuild?

Jeff
 

ScottinAZ

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the 2.5 morphed into the 3.0 which was used for MANY years after the 2.5 went the way of the dinosaur. Internal engine hard parts, such as what you are looking for are likely the same or interchangeable with the 3.0 of at least some vintages, and also automotive equivalents. This does not apply to gaskets. Gaskets MUST be marine type if they seal the cooling system, lest they live a very short life and ruin your day.

I have a 1980 vintage 2.5 in one of my boats, and it has given ZERO trouble. unless its high hours or very neglected, they are pretty troublefree.
 

Alumarine

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if you google "sealed power marine catalog"
you can find most of the parts you need.
A lot of the parts were used in other GM motors.
 

Bondo

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I just bought another Starcraft I/O 1980 2.5l 120. I've looking for engine parts and looks like a lot of the hard parts are unavailable, like timing gears and such. I probably should have done that before buying it. Are the internals in fact unavailable, say I want to do a rebuild?

Jeff
Ayuh,.... It'll be way cheaper, 'n waay easier to just buy a rotten boat with a 3.0l in it, 'n swap it out,.....
Then, you'll have a spare drive, 'n all the other parts,.....
 

matt167

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Ayuh,.... It'll be way cheaper, 'n waay easier to just buy a rotten boat with a 3.0l in it, 'n swap it out,.....
Then, you'll have a spare drive, 'n all the other parts,.....
Agree, I did this and ended up swimming in parts.
 

wvmedic

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Thank you for the replies, I wasn't sure if the internals were the same. I attempted to find sealed power marine parts, but came up empty. I have considered buying a rotted boat for a good running gear and just might go that route if I need another power unit.
As of now, I know the motor has a noise in the front of the motor. I am hoping that it is the water pump, though I have not started trouble shooting it yet. Just doing a little pre planning.
It has been to hot for me to do much with it outside. But I plan on doing a compression check and going over things, someone has cobbled a bracket for the alternator for sure. So with that being said, I don't know what else has been jack legged......

Jeff
 

Scott Danforth

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The timing gears for the 120 hp 2.5 liter have been available since 1962. Same parts as the 153 in the Nova ii, same parts as all the 196/230/250 inline 6

Agree to swapping to the 3.0
 

wvmedic

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So if I buy another boat for the complete running gear. What years will be a direct fit for the 3.0l and outdrive to fit the transom where my MC-I came out?

thank you for your help, Jeff
 

Bondo

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So if I buy another boat for the complete running gear. What years will be a direct fit for the 3.0l and outdrive to fit the transom where my MC-I came out?

thank you for your help, Jeff
Ayuh,....... The Gen.II Alphas came out in '91, so previous to that,......
In 1990, the rear main oil seal changed, so there a possible issue there, unless you get the entire package,( flywheel, coupler, etc),....
 

matt167

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1977 and newer the cutout changed just a little ( need trimming ) and I’m not sure when the exhaust changed but by the mid 80s the riser and manifold is different
 

wvmedic

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Bondo, If I go that route. I will absolutely do the whole package.

Thank you for the information, I appreciate it.
Jeff
 

Scott Danforth

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I personally would get a 1992 or later prop to pully setup to get the newest drive and motor combination.
 

wvmedic

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Scott Danforth, look over my ignorance please. But I don't understand what you mean.

Jeff
 

wvmedic

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Prop to pully?

Disregard, I get it. Dense moment on my behalf.
Get a complete Alpha one gen 2 unit.

Jeff
 
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wvmedic

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So the Alpha one gen 2 will fit the MC-I transom profile?

Jeff
 

Bondo

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So the Alpha one gen 2 will fit the MC-I transom profile?

Jeff
Ayuh,...... At worse, it might take abit of trimming,..... or not,.....

You will need to drill 2 more holes, for the extra 2 mounting studs,.....
 
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