Merc 3.0 upgrade to 3.7? Life expectancy?

[ktisdall]

I'm looking at a 1980 Aquasport Family Fisheman 19'6" with a merc 3.0 and alpha 1 stern drive. Used in salt water. Claimed engine hours are 200.

The boat is shrink wrapped so I have only inspected the outside so far. Drive looks clean and not corroded and I will be looking at the engine. Not sure I can get them to run it for me given that it's January. I did check the boat for hull moisture and the results were good. Transom and bottom were drier than most other boats I've checked.

Question is, how much life might that motor / outdrive have? Are the exhaust risers an issue on these?

Can the engine be repowered with a 3.7 merc? Would I need to also change the outdrive? The max hp for the boat is 185.

Not sure what the boat weighs. The brochure on-line said 2100lbs dry. Also saw 2800lbs.

Any thoughts would be helpful. I have experience with inboards and outboards but not i/o's.


--Kevin

 

[Bondo]

Re: Merc 3.0 upgrade to 3.7? Life expectancy?

Ayuh,.... Welcome Aboard....

Properly maintained, the 3.0l will last as long as the SBC, or BBCs will...
Their lives are measured in Thousands of hours...

The 3.7l is a Dead Horse,...
No longer produced, 'n No longer supported by Merc, parts wise...
As quirky as they were, Why O why would you even consider it,..??

 

[ktisdall]

Re: Merc 3.0 upgrade to 3.7? Life expectancy?

Only thinking of the 3.7 because 1) as I said, I know nothing about these, and 2) the boat has a max of 185hp and that might have been a repower choice, considering only hp.

Also - what are SBC and BBC?


A question I forgot to ask was if anyone had a rough idea of fuel consumption on these engines? WOT and cruising speed?


--Kevin

 

[86 century]

Re: Merc 3.0 upgrade to 3.7? Life expectancy?

The 3.0 is one of the best eng ever made(IMHO)you haft to try to tear them up.

As said above the 3.7 was a bad idea from the start with a lot of one off parts.

The fuel it uses will all depend on how you run it
Mine would go a full day 6+hours pulling tubes and wakeboarding on 20 gallons.
Good luck

 

[RogersJetboat454]

Re: Merc 3.0 upgrade to 3.7? Life expectancy?

Also - what are SBC and BBC?

SBC= Small block chevy
BBC= Big block chevy

The 3.0L is made by GM, and just as resilient as the previously mentioned engines, as long as it's been well cared for.
The 3.7L was Mercury's stab at building their own engine. The aluminum block is Mercury's own, the head was borrowed from a Ford 460, and the charging/cooling system was designed by an engineer who was hopefully fired by Mercury.

While several forum members here are living with a 3.7/470, and doing OK. I dare to say most will probably tell you this move would be an invitation for pain.

 

[ktisdall]

Re: Merc 3.0 upgrade to 3.7? Life expectancy?

Thanks much.

I found out more about the boat. Turns out it's a 22-2 aquasport not a 19-6. But the i/o is a 2003 merc 3.0 with alpha 1 gen 2 complete fresh install with a new fuel tank. Problem is that the boat is too big for what I want and I think may be a bit under powered.

Anyway thanks fo rthe info. Still looking.

--Kevin

 

[Don S]

Re: Merc 3.0 upgrade to 3.7? Life expectancy?

Being a 2003, you need to find a 4.3L V6. There are no exhaust tubes to hook up to a 3.7 with a Gen II outdrive.
Not only will you need the complete engine, but also a new upper for your sterndrive with a different gear ratio.

Suggestion, sell what you have while it runs, and buy something with the power you want. Conversions are not easy, or cheap to do and get it right.