Empty the fuel filters into clear glass jars. Look for clarity, lack of
suspended contaminants,or water at the bottom, It should not smell like
varnish. It should have a strong gasoline odor. Verify that the plug wires
are on correctly and the base timing is correct. If you have had wet weather
recently, pull the caps and make sure they are dry. Lastly, you may need to
rebuild or replace the carburetors.
Jim
wrote in message
oups.com...
I just took my boat out of storage after 3 years. It had been
properly winterized and laid up. To ready it for use, I paid a
mechanic to replace plugs, distributor caps, drain fuel tank, replace
filters, change all oils, and re-tune engines.

I took the boat out and ran it only to discover it would not go over
about 1300 rpm on either engine (sterndrives - Bravo IIIs) and it
backfires badly. The engines start and idle fine.

I noticed there was still fuel in the tank, almost a quarter tank
according to the gauge. From memory that could be 40 or more gallons
remaining in a 160 gallon tank. I put in 60 gallons of fresh premium
and then put in another four bottles of 104 octane boost. The problem
did not improve at all.

Any ideas? I am taking the boat back to the mechanic, but I no longer
trust him since he delivered the boat back to me in its current
condition.

Thanks.