72' 140 merc

lilmandavis

lilmandavis

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upon further inspection of my merc out board inline 6, on almost every cylinder, there is about 1" of rust on the walls by the spark plugs. is it easy to disassemble the connectiong rods from the crank? or are they pressed in pins? id really like to tear it down and hone out the rust instead of putting the marvel oil in it. just think that would be way better on the rings. its torn down pretty far as i speak. all covers are off exept the intake plate, where the crank is. i have to order a full gasket set anyways. so id might as well go all the way with it. id feel better with the hone job i think. even though its a lot of work. the rings are free in the grooves.
 
tashasdaddy

tashasdaddy

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Re: 72' 140 merc

you need Clams or Tim to come in on this.
 
L

Laddies

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Re: 72' 140 merc

Once the crankcase is split the crank is easily removed out the back of the engine, the rods are removably with a wrench, to reinstall the crank in the crankcase with out ring compressers takes awhile. Before starting get a manual
 
lilmandavis

lilmandavis

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Re: 72' 140 merc

do you mean like a ring compressor or a rubber o ring compressor?
 
C

Chris1956

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Re: 72' 140 merc

The Merc Manual shows the mechanic using four straight ring compressors and two offset compressors to install the crank, rods and pistons. I usually disasemble the rods from the crank, keep the bearings seperate by cylinder number, and install the pistons one by one. You can use a screwdriver and your fingers to install. Then stick the rod bearings and cages to the rods with grease and install the rod caps.
 
lilmandavis

lilmandavis

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Re: 72' 140 merc

thats what i was thinking. doing them one at a time. i have an engine tray. it keeps everything in order by cylinder.
 
L

Laddies

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Re: 72' 140 merc

The crank, rods and pistons go in and out as an assembly, that is why you need a manual
 
lilmandavis

lilmandavis

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618
Re: 72' 140 merc

ok im ready to put the crank assy back in. just a few things, are the reed bodies supporting bearings or is there supposed to be some play in them. the main journal bearins are tight but the reeds boies seem a little wiggly is this ok. are they flow through or journals as well? doin one at a time would almost be a nightmare. ive got em all ready to drop in. carbon, rust and dirt free. what would be a good ring gap on an outboard like this?
 
jimmbo

jimmbo

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May 24, 2004
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14,605
Re: 72' 140 merc

Actually it is four offset and two straight ring compressors
 
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