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View Full Version : Mercury Tech 1997 175 efi problems


dalecarver
10-02-2011, 08:47 PM
help. i have a 1997 175 efi that has been rebuilt . it .030 over with vetex pistons , oil injection removed. the problem im having is after the mechanic said my boat is ready and i go run it to start the break in process . it will bareley get out of the hole , it takes along time to get on plane and this boat normally jumps onto plane more like a jet ski than a bass boat . before it blew the first time this boat ran really hard all the way to the high 60s to low 70s gps . man had to redo the rebuild because of an error on his part. boat is freshly built hopefully correctly this time . motor sounds good just no power at all on the low end and not very strong at mid to high range in short burst . i have ran 18 gallons of 25:1 oil thru it before i even cracked the throttle even close to wot. kept boat bow down and under load varying speed ., and would run awhile and fish awhile so it would cool all the way down then repeat .
any advise i just wanna be prepared when i carry it back again.
TEXAS20225
10-02-2011, 09:16 PM
IMHO 18 gallons aint enough gas to break in and 25.1 is too much oil i built over 50 motors last two years i do 32.00 for 10 gallons or so then 40 .1 from now on but i keep it under 4000 till i burn at least 30 gallons of fuel but if its running sluggish like it is something aint right and it would be hard to say without it being where you could listen and feel personally juts my .02
Alan Power
10-02-2011, 09:26 PM
Whats the compression like?
dalecarver
10-02-2011, 11:20 PM
I have no idea . I just picked it up last week he said it was ready to go . I ran 18 gallons of fuel mixed 25:1 thru it . I haven't put a compression gauge on it . Motor sounds smooth idles ok . Just no power . The last time it was redone it ran much stronger initially even thru the breakin . I just had a cylinder go down and found out that it was not assembled correctly. Mechanic honed it and never checked it with gauge. Machinist told me every hole was a different size one was. .020 with a standard piston in it. That's why I had it punched to .030 and six new pistons.