You have a suspect electrical connection somewhere. The trim pump draws
considerable current. With a bad connection somewhere this will cause a
noticable voltage drop for anything else sharing that connection. The more
current you draw through the resistance of a bad connection the more voltage
drop there is. Aa boats age the surface corrosion increases on the
connectors. I'd start with the big connections that are common between the
everything such as both ends of the battery cables. Remove, wire brush, and
then reattach. I added stainless steel inside star washers to a number of
my larger bolt on connections between or under the lugs. The star washers
bite into both sides and make sure you have a really good metal to metal
connection.

wrote in message
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I have a 2000 454 mercruiser with 200 hrs.
Each year I've noticed the alarm would sound and the engine would
temporarily lose power as soon as I hit the trim switch.(On plane
3000rpm) This seems to only occur once or twice a year.
The guages all read normal and all fluids are normal. Any Ideas?