Thanks, Mike,

So far, I replaced the spark plugs and since then have had no trouble. That
doesn't mean the trouble is over, but preliminary indications are good. The
electrodes or whatever they're called were black, and there was oil on the
screw threads, moreso the further aft on the engine (which sits a bit lower
than the front) ... what this means I have no idea and so far no one else
I've asked does either. I checked a few of the gaps and they seemed about
the same as on the new plugs, around 0.032".

I'm also going to replace the leads just for thoroughness.

The engine was compression-checked four years ago, about 500 hours of
running time, so a lot might have changed since then. But, although it uses
oil, it doesn't use much. I put in a litre only every 50 hours or so (which
is about when I should be changing it anyway).

Thanks again.

Charles

====

Charles T. Low
www.boatdocking.com

====

"Mike G" wrote in message
ews.com...

A couple of things come to mind but the top of the list one is that you
are running rich and loading up the engine at the low RPM and the good
run at WOT is cleaning things up.

A compression check probably wouldn't be out of order either since the
second item on the list is a question of how well the valves are
seating. Especially if you do a lot of trolling. five hundred hours of
more low RPM trolling then high speed operation can give you quite a
build up of carbon which may be getting to a point where the seating is
only marginal.

There is always the hotter plug thing but since I'd only consider it if
you were doing a whole lot more trolling then running at WOT. I'd only
suggest it after you gave things a lot of thought and a second opinion
from your mechanic.

I know it doesn't address the manifold thing but.................

Good luck


--
Mike G.
Heirloom Woods

www.heirloom-woods.net