Lawnmower Engine Replacement

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Threads should be reverse.
Searcher
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.