rebuilding a merc 140

[big jilm]

i can pic up a 1975 or so merc 140 for pennies on the dollar. word is it runs fine. i would like to rebuild it for a fresh start and more power. are there any perf parts i can use, and how much might this cost me? also , what kind of hp gain can i achieve? this would be a second motor for me so im not worried about geting it finished till next year. any info would be great.<br /><br />matt<br /><br /><br />__________________

 

[Mercury140-I6]

Re: rebuilding a merc 140

Hello and Welcome to the board:<br /><br />As I understand it, 140hp at the crank 115hp at the prop (Same thing basically) is the most you9 canb get out of the inline 6 (99cid) and keep them together.<br /><br />Others will probably have a better insight to this and will chime in soon.<br /><br />Hope this helps.<br /><br /> http://www.myfishingpictures.com/showphoto.php?photo=13002&sort=7&thecat=500&password= <br /><br />Craig

 

[jimmbo]

Re: rebuilding a merc 140

The merc 1400 was made in 1972 and again in 1978, it was called a 140 in 79 and 80. there were several changes in the motors. the later years had power ported pistons, the pre 79 motors had distributor ignition while the post 78s had it under the flywheel. Overall very good and well engineered engines.

 

[andrewkafp]

Re: rebuilding a merc 140

The best member to talk to could be ZmOZ who owns one and is looking to rebuild. Think his is a 73-74 150.. inline<br />As Jimmbo said, the post 78 ones had the coilpack ignition consisting of 1 coil per cyl driven by a trigger. Prior to that were coil and a dizzy.

 

[big jilm]

Re: rebuilding a merc 140

see i own a 78 merc 115 right now. its on a 16' checkmate. it runs great. but im looking for that lil bit more. would i see a diff. if i were to put the 140 on it?

 

[jimmbo]

Re: rebuilding a merc 140

About 4 mph and some loss of holeshot. If you really want see a difference get a 135 V6.

 

[andrewkafp]

Re: rebuilding a merc 140

Or if you own a bank...<br />This supercharged model may do the trick..<br />

 

[powertower]

Re: rebuilding a merc 140

Originally posted by Mercury140-I6:<br /> Hello and Welcome to the board:<br /><br />As I understand it, 140hp at the crank 115hp at the prop (Same thing basically) is the most you9 canb get out of the inline 6 (99cid) and keep them together.<br /><br />Others will probably have a better insight to this and will chime in soon.<br /><br />Hope this helps.<br /><br /> http://www.myfishingpictures.com/showphoto.php?photo=13002&sort=7&thecat=500&password= <br /><br />Craig

 

[powertower]

Re: rebuilding a merc 140

Get it on a dyno to see what your timing is. If it is 20 or 21 degrees - it is too low and you are not making the horsepower. Also run the best fuel and oil you can. This is my amateur suggestion.

 

[emckelvy]

Re: rebuilding a merc 140

DO NOT under any circumstances run more than 21 deg of advance at WOT. Usually recommended to run a bit less than that, between 18-21. <br /><br />If you run more advance than that the motor will burn pistons.<br /><br />Also make sure WOT is around 5800 rpm. These motors don't like to be lugged and this can also cause detonation and burnt pistons.<br /><br />Avoid use of alcohol-mixed fuels and use a good grade of TCW-3 or better oil.<br /><br />The best way to optimize performance (besides a good tune-up) of your 140 would be thru use of a stainless prop of correct pitch, intallation of power trim/tilt, and mounting of the motor on the transom at the correct height.<br /><br />The 140 will definitely improve your top end, and of course increase fuel consumption.<br /><br />HTH........ed

 

[big jilm]

Re: rebuilding a merc 140

what should i pay for a 78 merc 140?