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John Wentworth
 
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Default Mercury Marine 470 / 3.7 Liter

"Glenn Deneweth" wrote in message
...
I was told by my mechanic that these are not very good engines. Does

anyone
how any comments? Are they difficult to rebuild? Expensive?


I owned a 470 for over 10 years and got excellent performance from it. I had
no significant problems with the engine, although I did have a serious
problem with the outdrive due to my own laziness (stupidity?). The motor is
Mercury-built (I've heard it's based on a Ford tractor block, but ???),
unlike it's peers which are GM or Ford auto engine based. That does mean you
won't be able to purchase engine internals from an auto parts store so that
could increase the cost of a rebuild. All 470's are closed-system cooled, a
nice feature if you run salt water.
Early versions had problems with the alternators ( a constant current idea
that didn't work out too well), but that should have been resolved years
ago.It's an easy engine to work on for regular maintenance, and winterizing
is straight forward. Compression ratio is 8.8 to 1, and the manual calls for
compression pressure to be 150psi with an allowable variance of 20psi
between all cylinders.I always ran premium fuel, the manual calls for 88
octane. (if it's pre-1975, leaded fuel is recommended). Oil pressure should
be 30-55psi at 2000 rpm and it holds 5.5 quarts of oil.

I can't give you advice on degree-of-difficulty for an engine rebuild, I
never got the "opportunity" to rebuild mine.