1980's Snapper 21's Build one mower from two.....

[Zack1978]

Hi everyone,
I recently added two lawn mowers to my collection, a self propelled 21405PS and a non self propelled 21351D. Both machines have worn engines, however the non self propelled machine is totally original as opposed to the self propelled machine that has had an engine replacement and the safety bail has been disabled as well as the throttle control. The self propelled machine is also in generally worse condition than the non self propelled machine.
With the above in mind, I was thinking of using the two machines to build one mower. Are the decks on both machines the same? From my untrained eye, they look to be the same. Can all of the self propelled parts be swapped to the non self propelled machine, to make it into a self propelled machine? What else must I keep in mind to accomplish my goal?
Also with respect to an engine replacement, what is the most direct bolt in engine available for these machines? I have read a few threads where people mention using the Harbor Freight engine (5.5 HP (173cc) OHV Vertical Shaft Gas Engine CARB), is that an easy and viable option? What other choices may be available?


Thank you,
Zack

 

[Snapperfreak]

To answer the first question, yes all the parts on those 1980s steel deck snappers are interchangeable. On the rear axle from the self-propelled model, when u swap that over it's easiest to unbolt the brackets that attack the handles to the deck so that u completely remove everything back there in one piece (rear axle, wheels, handlebars). I can post a pic of mine to better explain when I get home. Can't help as far as new engines though, I haven't transferred a new engine onto any of mine, only old engines that came on other snappers of the era. I will return later tonight with pics for u about where to unbolt the stuff on the self-propelled one.

 

[Snapperfreak]

Ok those three bolts (two on side one on top) are what will detach the entire rear axle and handlebars from the deck. Then remove the bracket holding the disc drive stuff. The pusher deck will have the holes on top of the deck behind engine to bolt that to.

 

[OutdoorEnvy]

I recently put a newer 675 series B&S engine on a 1983 deck like yours. One hole lined up and I drilled two more. This was pretty easily done and it is working great. When I was researching engines a lot of Honda engines said they were a replacement for Snapper. This link is to Honda vertical engines Object moved. I will probably look to get one of these when needed.

cool project though. I'm hoping to have mine wrapped up at the end of this month.

 

[cashman]

The length and diameter of the crankshaft should match and see if the air cleaner and fuel tank location don't interfere with the self propel mechanism. Measure the crankshaft sticking out the bottom of the engine and see if the length and diameter matches what's on the 6.5hp vertical shaft engine listed at Harbor Freight? If I remember right, the original cranks used on Snapper walk mowers had a keyway that went the full length of the crankshaft for the self propel pulley and the drilled and tapped for the blade mounting bolt. The Chinese engines might use a different thread than the original on the blade mounting bolt? The engine mounting bolt holes might have to be re-drilled if they don't match. If the Harbor Freight engine has a blade brake on it, something might have to be rigged to accommodate that.

 

[Zack1978]

Thank you for the tips everyone. I have a few more questions. The machine could use new wheels all around. Where is the best place to source new wheels? Are the self-propelled wheels special in any way? Will new wheels also come with new bearings? Hopefully new bearings will make the wheels tight on the shaft. If I have some ime this weekend, I will get started on this project.




Zack

 

[Snapperfreak]

K&T parts house dot com has good prices on new wheels. Yes the rears on self-propelled models are slotted to fit onto the rear axle. 7x1.75s fronts and 9x1.95s rear, steels would be best. The wheels don't come with bearings as those are part of the wheel height adjusters but when u put a new set of wheels on your mower will roll much smoother. I was very pleased with how much better it felt pushing mine when I got a new set.

 

[Zack1978]

Another question....
How fast should the self-propelled machine go? In the fastest setting, should I basically be running behind it? I realize that this is a subjective question since we all walk at different speeds, but in general terms should it be moving fast?


Thank you,
Zack

 

[Snapperfreak]

Yes they're rated at a little over 3 mph in the fastest setting, which is pretty quick as far as I'm concerned. I'm 6'3" tall and in 6th gear I'm walking very quickly behind the mower. Personally I rarely mow higher than 3rd or maybe 4th, above that is just too fast for my preference. Bottom line, it'll be pretty quick.