what do you like about your mercruiser 3.0 ?

johnzonh

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hey everyone, I am going to pickup a 1988 Marathon with a Mercruiser 3.0 in it... the boat has been very well cared for and it seems the owner has been really using it... good records, etc. It is a closed cooling system and I believe it is 165 HP. Just wondering for those of you that know this motor, what do you like about it? any quirks? things I should be looking out for? Thanks for the heads up.... :)

john
 

Bondo

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Re: what do you like about your mercruiser 3.0 ?

hey everyone, I am going to pickup a 1988 Marathon with a Mercruiser 3.0 in it... the boat has been very well cared for and it seems the owner has been really using it... good records, etc. It is a closed cooling system and I believe it is 165 HP. Just wondering for those of you that know this motor, what do you like about it? any quirks? things I should be looking out for? Thanks for the heads up.... :)

john

Ayuh,.... Sure don't sound like a 3.0l, which at Best is 140hp,....

It sounds more like the infamous 470, 3.7l, Mercruiser's redheaded step-child, they've forgotten,...

Many. Many parts are NLA, so it's basically Obsolete,...
If ya haven't bought it,.....

Don't,....
 

eavega

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Re: what do you like about your mercruiser 3.0 ?

+1 Bondo's reply. That's probably the 470, not the 3.0l. Just do a search here on iboats to see some of the possible issues with this motor. 1988 is about the right year for them, too.

-E
 

superbenk

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Re: what do you like about your mercruiser 3.0 ?

If it's a 3.0L it'll be 140HP as mentioned. If it's 165HP it'll be a 470 also as mentioned. Totally different beasts. I didn't have a Mercruiser but I had a 3.0L OMC and the engine was great. It was really easy to work on and ran flawlessly (for the most part barring it's age). It was simple and solid. But... That's a 3.0L. Like I said a 470 is a completely different beast and one I wouldn't touch.
 

johnzonh

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Re: what do you like about your mercruiser 3.0 ?

im looking into it. downloading service manual to hopefully identify this... has been noted in many places as a 3.0 so we will see.
 

thumpar

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Re: what do you like about your mercruiser 3.0 ?

An easy way to tell if it is a 470 is to look where the carb is. If the carb, intake and exhaust manifold are on the port side it is a 2.5l/3.0l. If the carb is starboard and the exhaust is port it would be a 470 or variant of it.
 

HT32BSX115

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Re: what do you like about your mercruiser 3.0 ?

An easy way to tell if it is a 470 is to look where the carb is. If the carb, intake and exhaust manifold are on the port side it is a 2.5l/3.0l. If the carb is starboard and the exhaust is port it would be a 470 or variant of it.

Another couple of ways to tell is the ALUMINIUM head and the heat exchanger (although some 3.0's could have closed cooling) BUT no 3.0L has an aluminium head!
 

Bondo

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Re: what do you like about your mercruiser 3.0 ?

Another couple of ways to tell is the ALUMINIUM head and the heat exchanger (although some 3.0's could have closed cooling) BUT no 3.0L has an aluminium head!

Ayuh,... It's an aluminum Block, 'n cast iron head Rick,....:rolleyes: :lol: :laugh:

Yer still My Hero though my friend,..... ;)
 

HT32BSX115

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Re: what do you like about your mercruiser 3.0 ?

Ayuh,... It's an aluminum Block, 'n cast iron head Rick,....:rolleyes: :lol: :laugh:

Yer still My Hero though my friend,..... ;)
Yeeeeeeaaaaahhhhh.........You know I meant Aluminum BLOCK:facepalm:
 

Lou C

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Re: what do you like about your mercruiser 3.0 ?

A Ford 460 head with a Merc cast Alu block and closed cooling. I'm not sure what they were trying to accomplish with this combo but you'd be far better off with the common and simple Merc 3.0 4 cyl, about the simplest thing ever built besides a carbed 2 stroke OB...
 

HT32BSX115

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Re: what do you like about your mercruiser 3.0 ?

A Ford 460 head with a Merc cast Alu block and closed cooling. I'm not sure what they were trying to accomplish with this combo but you'd be far better off with the common and simple Merc 3.0 4 cyl, about the simplest thing ever built besides a carbed 2 stroke OB...

It actually worked pretty good as long as you didn't get it HOT or until it needed a new alternator! Then things went downhill pretty quick.......
 

Lou C

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Re: what do you like about your mercruiser 3.0 ?

Honestly they should have stuck with the inline 250 cu in Chevy six, a very nice and easy to maintain engine for inboard power (long though), inline 6 pluses is perfect primary and secondary balance, no inline 4 can have that unless it has a balance shaft.
 

Howard Sterndrive

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Re: what do you like about your mercruiser 3.0 ?

I think in the 1980's, if GM could have seen 30 years into the future to see that the 3.0 would still be going into new boats in 2014, they would've designed an overhead cam version maybe a 3.2L or so, and get a modest 175Hp out of it that would fill the HP gap between the 135HP 3.0 and the 190HP 4.3 V6
 

Lou C

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Re: what do you like about your mercruiser 3.0 ?

Agreed a nice cross flow head, OHC + balance shaft would have nicely updated that engine.
 
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