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Engine swap Tecumseh HMSK100 / Briggs 20C414

8.3K views 32 replies 7 participants last post by  ORioNs0785  
#1 ·
I have an old MTD mastercut snowblower 30" from the 80s that I have restored and the old original Tecumseh HMSK100 engine still gives me good surprising power but has several problems at the level of reliability lol. I have a Briggs & Stratton 20C414 engine that I picked up on a Craftsman blower at the trash that I have restored everything and it works perfectly but I have never blown with it, it's like a new. I intended to make a motor swap, I ordered a Sleeve adapter for 1 ", a new steel base. The base of the engine is bigger but I looked and I think I think have even the holes already pierced on the transmission of my snowblower. I should proceed this spring and I do not think I should have too many problems but I have questions... On my engine briggs it's written 11.5HP Basically, what is better than my current 10HP ;p but when I look at the specs it's only a 305cc while my tecumseh is 358cc. I know that the briggs is a much more recent ohv motor but is it's worth it and I'll see a positive difference in performance with this engine because it has a smaller cylinder? I live on the corner of a street and I have a lot of heavy snow with gigantic hem of snow and roof unloading, am I better to keep my old Tecumseh in terms of Performance? Is it true that a 305cc briggs is a 11,5hp or just a fake?
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#4 ·
The old engine it works, two years ago I cleaned and adjust it it and painted the panels but his age is there. I blow the snow for 4 hour in lines during a big snowstorm and it always arrives a problem... he stumbles a little bit, there I have to change the lines in a gasoline because they disintegrates and block the carburetor with black particules that I cleaned several times this winter. This same carburetor is very old and the stems are very worn, I have new carburetors and I try them and I'm never able to adjust it so that the engine runs well. There is the rods of the governor who is really worn, I start to see black flowing where the head and surely that the head gasket will have to be changed. The muffler becomes a little red when I have my engine forcing a lot, I would have to check the exhaust valve... In short there is a lot of work to do on this engine and I am able to do it but replace pieces It also costs money too. The other briggs engine I have it and it is all in working order, it's a lot less work to replace this old tecumseh by this engien I believe... but at least to know that it is at least Also powerful...

As for the snow blower, I really like it and and blows the snow really well, besides the engine it works like a new one. When I restored it, I changed bearings, bushings, a sprocket in the transmission, Wires etc. etc.

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#3 ·
You will most likely have to change belts, as the crank height on the briggs is different. You will also have to drill new holes, as the briggs footprint is different as well.
 
#5 ·
Thank you for telling me, I looked fast and it seemed the same thing. There I just got measured over an old Tecumseh 8 HP that I have and it seems the same height between the base and the shaft, the mounting holes on the front of the engine have the same distance too
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#6 ·
I re-did a Yard Machines 11.5hp 28" blower late last year. The 11.5 broke the rod but the guy inc. a 10hp Tecumseh engine with the deal. After some messing around getting the pulley system right I got to test it out in Dec. of last year. The 28" machine worked very well and I am not sure id the extra little bit of hp would be any better. With the impeller mod it blows snow as good as my 11528 Airens does. You have a nice blower there and it should serve you well.
 
#7 ·
Ok so if I understand your briggs 11.5HP Broke A Rod and you replaced it with a Tecumseh 10 hp and it's so powerful? So at least if the performance is the same is the same it satisfies me lol.

For the snowblower I can confirm that it blows really well and I love it especially with the turbine of 14 "and the chute of 5" in diameter, even the big wet snow never blocks
 
#13 ·
Yes indeed we see the distance between the holes it is really that distance, the base of the Briggs Stratton is much larger. But I find it odd that you all tell me that the height of the crank is different and even with the adapter that you show me it proves... I just measured and re-measure and in my it's exactly the same Distance for my 2 engines :s
 
#14 ·
Good luck with your first swap.
 
#16 ·
Hello! Last spring I finally decided to convert the engine and I had not taken the time to give you the report. After a small absence on the forum and the arrival of winter and snow blowers, I decided to take the time and come and show some images of the finality and during the conversion, if it can give ideas to someone...

To be honest with you everything went very well and I had no difficulty, the only thing that took the most time was to convert the accelerator cable but I improvised a little and that works perfectly. For the base, I used a larger steel plate but the same thickness than the original one (1PO) with 4 holes for the bolts. To use the same pulley I used an adapter of this type https://fr.aliexpress.com/item/4000...4000538516880.html?spm=a2g0o.order_list.0.0.3a6c5e5bhw1I6P&gatewayAdapt=glo2fra which fitted surprisingly perfectly without in any loose. I used the same belts and even the front bolts on the black plate are at the same places, everything is perfect.

Currently in Quebec we are still in autumn but we received a little snow last week and I was able to try it and everything worked well. I cannot tell you if the engine offers the same performance despite its smaller displacement but one thing is certain it runs like a new one. to be continued...


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#19 ·
Ahah indeed my tires are dried and cracked I even have tubes in it. It would be an investment to do indeed, I have X-Trac on my other snowblower but I find them less effective in the wet and sticky snow, it looks like the crampons are too large and all the snow sticks on the tire and I have no more traction. I believe that X-TRACs are more effective when the tire is not wide, but it is only my opinion.
 
#21 ·
i would agree that the Xtrac tires are better traction over all. if you wanted narrower tires you could always get narrower rims. they are still pretty common rims. what part of Canada are from?
 
#32 ·
I do many tire changes ...A long time ago, I actually picked up a mini tire changer from Harbor Freight, like your Princess Auto, ..... but for anyone doing just a pair, might use a fire store to change them, or a small dealer repair shop, or a friend with one. Makes it a lot easier ..... Also make sure the rim is cleaned, prepped and painted at this time, with possibly new valve stem to go back to tubeless as they are.