Mercruiser 120 question

[woodrat]

I am looking at a 69 Fiberform with a 120 mercruiser engine . Is that a GM engine? It allegedly had the outdrive replaced three years ago, and all it allegedly needs is a outdirve water pump impeller. If it's a GM motor, the standard "chevy II" one, I would consider buying it, but I am new to the whole wide and confusing world of inboard/outboard and want to make sure that this is likely to be a decent engine design and one that I could get parts for.<br /><br />Thanks<br /><br />Mark

 

[Laddies]

Re: Mercruiser 120 question

That a 153 cu. GM engine

 

[woodrat]

Re: Mercruiser 120 question

are parts generally available for that? Is that the same as the "iron duke" car engine?<br />Thanks<br /><br />Mark

 

[Laddies]

Re: Mercruiser 120 question

Parts are very available, no it is not a iron duke

 

[Haut Medoc]

Re: Mercruiser 120 question

Yes on the parts......Nice Fish!.....JK

 

[woodrat]

Re: Mercruiser 120 question

Originally posted by Medoc:<br /> Yes on the parts......Nice Fish!.....JK

Thanks! The fish came from the ocean this summer, a couple of trips before my Valco skiff developed a big fat crack in the hull, beaching me for the rest of the season. I have an appointment with a welder next month, but I am looking at going to a deeper V glass hull with an inboard gas engine that I can understand and afford to buy parts for, and that is a little better designed for rough water. My Yamaha is EXPENSIVE to get anything for, and the parts are never available locally. There seems to be a lot of older I/O boats needing minor or major repairs, going for pretty cheap. <br /><br />I am likely to see a lot of fuel economy difference between this 4 cylinder Gm and the usual 250 CI 6 cylinder that I am alos finding a lot of? I've been mostly looking at just the sixes since they are familiar engines to me, but if the fours are good I would consider one of those too.<br /><br />Thanks for the help!<br /><br />Mark

 

[Haut Medoc]

Re: Mercruiser 120 question

Fours are good... ....Stay away from anything O.M.C...... ....JK

 

[woodrat]

Re: Mercruiser 120 question

is a 125 mercruiser a different engine than the 153 CI chev?

 

[Eggkr8]

Re: Mercruiser 120 question

Hey Woodrat. I got a Mercruiser 110. It is the same displacement as the 120 (153 ci). It is kinda the older brother of the 120. I can still get parts for it no problem. The 120 was used for years, there are many out there and parts are plentiful. Even NAPA Automotive carries marine parts and at good prices too. For anything that is oddball, I would recomment www.dougrussell.com. Their parts guy Jeffrey is a big help<br /><br />I may get disagreement on this statement, but I looked and looked and I would say that this is the marinised version of the Chevy 153 CI block that was used in the Chevy II and early Nova's. I do not know if there is a different crank, connecting rodas, pistons.. I am pretty sure the upper engine components (cam rockers, lifters, ) are different

 

[Fishermark]

Re: Mercruiser 120 question

Actually I believe the 120 IS the same as the "Iron Duke" - at least the block and internals. It is NOT the same as the 3 liter engine, which is not a car engine. As always... "I could be wrong."

 

[Bondo]

Re: Mercruiser 120 question

difference between this 4 cylinder Gm and the usual 250 CI 6 cylinder

Same Motor,...........<br /><br />Just 2 holes Shorter..............

 

[rodbolt]

Re: Mercruiser 120 question

the "iron Duke" was a nickname that was given to the pontiac 151 CID 4cyl. was put in a lot of GM autos but not much else. the 153 was about the same in the marine as the auto version. a bit of work with the part numbers will tell ya. I think it was at various times a 110,120,135,140 and there may be another I forgot.

 

[gatorred]

Re: Mercruiser 120 question

it based on chev 4 cyl but merk block is little bit odd,but car engine will fit, nice fish

 

[Bondo]

Re: Mercruiser 120 question

it based on chev 4 cyl but merk block is little bit odd,but car engine will fit,

I don't know exactly What you're saying,.......<br /><br />Both the 153cid, 2.5l,+ the 181cid, 3.0l ARE GM/Chevy Blocks,......... <br />Merc. Hasn't/ Doesn't Change the Long Blocks,... At All....... They just Add their Accessories............<br /><br />BTW,...... Neither of these engines have been used in a Car since the Early/ Mid-60s,.........<br />And,...... The 3.0l has Never been used in a Car............<br />

want to make sure that this is likely to be a decent engine design and one that I could get parts for.

Ayuh,......<br />The 2.5l is Not much of a Powerhouse,... But,.. it's a Dependable Proven design that has been produced since the 60s,......<br />And,... Has Been,+ Is Very Well supported by Both the Original Manufacturer,+ the Aftermarket Parts Suppliers...........

 

[woodrat]

Re: Mercruiser 120 question

Originally posted by woodrat:<br />

want to make sure that this is likely to be a decent engine design and one that I could get parts for.

Ayuh,......<br />The 2.5l is Not much of a Powerhouse,... But,.. it's a Dependable Proven design that has been produced since the 60s,......<br />And,... Has Been,+ Is Very Well supported by Both the Original Manufacturer,+ the Aftermarket Parts Suppliers...........

That's the kind of info I'm looking for. At this point I 've figured out that I would be OK with either the 2.5 l four cylinder or the Gm straight six. Manifolds are an issue, but general parts availability isn't really. I'm trying to stay away from OMC drives and stick to Mercruiser. And the "Iron Duke" that i've encountered in cars is acutally a 151 CID engine, which means that it must be at least a little different than the mercruiser/GM 153 CID, which as near as I can figure out, was a Chevy Nova engine in the 60's..<br /><br />whew! The learnin' just never ends!

 

[Trent]

Re: Mercruiser 120 question

Yep.. The Nova was in the 60's<br /><br />Dont remember all the years.. But the 1965 Chevy II Nova was the same as the 2.5L Wish I could remember all the years but my brain is full! If I learn anymore that means I have to forget something else! God help me...