K&B 3.5 Outboard - Conrod Compatability

[kesso2118]

I have an old model 3.5cc Outboard (black carb) and I needed to replace the conrod (big end disintegrated).

I thought I would do the right thing and replace bearings & PTO Shaft.

I looked up the parts list, doubled checked everything, placed my order over the Internet (I'm based in Sydney Australia) and waited patiently for delivery. The parts arrived after about 2 weeks, so far I'm pretty happy.
I was impressed by the sturdy appearance of the conrod.

I've now done all the hard work removing bearings, cleaning everything, installed new bearings.

Began re-assembling and went to do the easy part i.e. install new conrod.

To my complete surprise and DISAPPOINTMENT I find the conrod I ordered as per the parts list doesn't fit the piston i.e. the little end doesn't have sufficient clearance inside the piston and I cannot insert the wrist pin.

HELPPPPPPP!!!!

The parts list shows the Part No. 16 - 8902 for the old model, however, on the Order Page it says for Part No 16 - 8902 use 16 - 8901.

What can be done ???????

Now I am no longer happy, I have a Race Meeting in 5 days and it l looks like I ain't gonna be there!

[MECOA]

Well it is probably very close to fitting. You must have a very early piston.
The 3.5 used many rod designs over the last 30 years in that engine. Usually the place the rod will hit slightly is in the crankcase as it moves past the point where the crank and cylinder bores meet. A simple dremel

You can do 1 of 2 things to get you in the meet.

File the rod slightly. It is plenty beefy and if you use your old rod as a guide you will ba fine.
or
Using a dremel tool relieve the inside of the piston. I think it probably is only hitting at the top (deepest point) in the piston.

Sorry but it will fit 90% of the time in the older engines.