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Wrong Rod???


LawnSite Member
Nashville, TN
Hello Lawnsite!

You all may recall several months ago that I threw a rod in my 28Q777 15.5 OHV briggs. I had it running a while back, and I put it back on my mower a few days ago. The problem is that now I can hear a knocking from the engine, that I did not notice when I started it on my bench.

I opened up the crankcase today and tried to replicate the knock I was hearing. There was no play in the direction of the piston (up/down), but I could get a little wiggle in the direction of the crankshaft (maybe 50 thousnadths). It's almost like the rod is a little skinnier than the crank journal. So I got to thinking, what if I had gotten the wrong rod? Is there another engine out there with a smaller crank journal?

I'm stressing out b/c I am running out of running engines!


LawnSite Bronze Member
lee's summit, mo
Rod end play is fine. Keep looking for you knock. When it's running take a 1/2 inch rubber hose about 3 feet long. Put one end to your ear and probe around on the engine to help locate the noise. It may not be internal?


LawnSite Fanatic
It's probably the crank balancer you hear, The bearings wear as shown below and are non-replaceable. One must replace the whole assembly and range in the $100.



LawnSite Fanatic
Sure, They can be checked but you need inside and outside micrometers.

Here are the specs;

Briggs Balancer Specs.jpg