Replace just one connecting rod?

[MercMark]

I have a mercury 850 7033755 I think it's a 1974.<br /><br />I'm in the middle of a rebuild and my connecting rods don't look so good. They're CAN$180 each so I don't want to replace all four. I think I nicked one pushing out the wrist pin.<br /><br />The manual says nothing about replacing just one connecting rod. It always says "this SET must be replaced". The manual is usually very specific about saying parts must replaced on the same journal, facing the same way, needles in the same races they came out of etc...<br /><br />Can you replace just one connecting rod? and use two or three of the old ones?

 

[Chris1956]

Re: Replace just one connecting rod?

MercMark, What part of the conecting rods don't look good. The important parts are the bearing journals. If there good, your fine. If the journals are scored, pitted, burned (you get the picture), it will need replacement. I would think replacement of a single connecting rod would be OK, as long as you replace the bearings. Remember this is a 1974 motor. It can't be a good idea to put too much $$ into it. You can also get a rebuilt powerhead for $1500(US) or so.

 

[MercMark]

Re: Replace just one connecting rod?

^<br /><br />hoping for more replies to determine the popular opinion

 

[Chinewalker]

Re: Replace just one connecting rod?

If it were mine, I'd find a burned up powerhead with a bad piston and use it for parts. You'll likely find a whole motor of that vintage for less than one new con rod, and have lots of spares, etc. leftover. It is not a problem at all to replace a connecting rod singly - just make sure the rod caps get put back on the right rods and in the right direction, as each rod is machined bolted together and will only work properly when it is reassembled the same way. They usually etch some lines into one side of the the machined flats of the rod/rod cap to align them back together...<br />- Scott

 

[Reel Precision]

Re: Replace just one connecting rod?

they are actually one machined as one peice and then scored then broke into two peices making the cap and rod that only fits one way.