"Lloyd Sumpter" wrote in message
...
Hi,



Are outboards (esp.
4-strokes) designed to run WOT full-time? I know inboards are not, but
what
about outboards?


There are two issues when running at WOT: High RPM and heat.

It is common to have the propeller pitch selected such that WOT results in
the fastest possible speed, which is usually at the maximum RPM. Maximum
RPM is often stressing internal engine parts in such a way that they will
not survive long. It is also typical to get an excessive amount of blow by
and resultant loss of oil at high RPMs.

If the load on the engine is sufficient to keep the RPMs in check then the
next concern is heat build up. Even with an infinite amount of cooling
water (the lake) the engine may not be able to draw the heat away from the
hottest areas, specifically the piston tops and cylinder head. Prolonged
running at such conditions could burn a piston or a valve.

Rod