Lawnmower Engine Replacement

May 25, 2006 3 Replies
U

Hi.



I have an old lawnmower with a 3.5 HP Briggs engine. The engine is worn out after about 20 years of abuse. It has a 21" blade and the shaft measures about 2 7/8" to the flat part where the blade is inserted. The blade holder is attached to the crankshaft with a big nut. I cannot see the threads. Anyone know if this is reverse thread or regular? I found some new engines on eBay for cheap but they don't appear to be threaded on the outside of the shaft. Is it very difficult to find parts to fit a blade onto other kinds of shafts? I don't seem to be finding any with outside-threaded shafts.



Thanks.


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L

I don't know where to find the engine, but I can tell you a quick way to tell which way to turn the nut to loosen it:

carefully pull the start cord on the engine and note which way the shaft turns (may need a helper so one can watch and the other person can pull the cord). The nut/shaft will be threaded so that the shaft rotation tightens the nut (otherwise the lawnmower would throw the blades off every time you started it up).

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U

OK, thanks (to both of you). :-)

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