Alternative mod 50 rod

[OUTBOARDER]

Found a newer rod for the Long Rod MOD 50 Piston

1996 OMC 25/35 hp triple #0435895 4.25" Center to Center
Big end uses same bearing as 45, 49 or 56
Small end 5/8" dia Wrist Pin
$118.00

hope it helps

[Powerabout]

A std 56 rod is almost 4 1/4
I thought the md 50 rod was about 5 1/4?

[OUTBOARDER]

A std 56 rod is almost 4 1/4
I thought the md 50 rod was about 5 1/4?

49 Stock = 3.688" Center to Center

56 Stock = 4.000" Center to Center

Mod 50 = 4.250" Center to Center

Measured Center of Big End to Center of Small End

[Powerabout]

Many thanks
Great info

[Tim Kurcz]

Anthony & Co.,

Looking at the rods in my stash last night found length identical, but the bolts are very different. The 49.9 CI Mod-50 rod uses a 1/4" bolt, while the 35 CI mini-triple uses a 3/16" bolt. Though attractively priced and available, the Mod-50 piston is heavier and expected to turn 8000+ RPM, so I don't recommend the mini-triple con rod for 49.9 CI application.

Tim

[OUTBOARDER]

Anthony & Co.,

Looking at the rods in my stash last night found length identical, but the bolts are very different. The 49.9 CI Mod-50 rod uses a 1/4" bolt, while the 35 CI mini-triple uses a 3/16" bolt. Though attractively priced and available, the Mod-50 piston is heavier and expected to turn 8000+ RPM, so I don't recommend the mini-triple con rod for 49.9 CI application.

Tim

Lay both M50 and 35 rod out side by side and take some pics said the drill to the tap.
My camera is down and my sample is on the way.

Thanks,

[Tim Kurcz]

Hey Anthony,

As you can see there is no room for a 1/4" bolt. It's odd the designer wouldn't have commonized on the larger bolt, though I'm certain the 3/16" bolt is perfectly sized for the application. But hey, you might save 10 grams a bolt/rod combo and get a tighter crankcase as well. I recommend you locate some good used or NOS Mod-50 or RD series rods. Ahhh, just like looking for NLA Mercury parts. Good luck!

Tim

[OUTBOARDER]

WILL
Lay both M50 and 35 rod out side by side and take some pics said the drill to the tap.
My camera is down and my sample is on the way.

[Powerabout]

Every now and then someone mentions people used Merc rods in these engines.
Anyone know which rods they were?

[OUTBOARDER]

Saw a few ambiguous posts about Merc Rods s in the past.
Never had a chance to measure bottom end stuff at Local Outboard Junk Yard.
I am sure someone could shed some light.

A few years ago the Outboard Junk Yard scrapped all the old stuff and so I do not have
access to piles crank, Rods & pistons to measure now.

Found this possibility from 2007 Sport C Inspection sheet.
(JOHNSON, BP-48B, 34.9ci, 3 cyl) Rod Center length identical to mod 50 rod @ 4.25"
Went to BRP and crossed Big end bearing pt# to 2cyl 50.

Hope this helps, we will have to wait and see who steps up and actually posts some
information with pics in the name of reducing the cost of boat racing.