Honda 4013 Lawn Tractor | My Tractor Forum

Hello everyone this is my first thread on the forum. I have a Honda 4013 Tractor and want to fully fix it up, the tractor was the first tractor we bought at the house we live in back in the 90’s and used it up to 2008. I was a kid at the time when we used the tractor so I do not remember much of it, but I want to fix the tractor up because nothing cut the grass like a Honda, not only that but the 4013 is rare because most people gut them for parts for the 4514 and 4518’s. We got the tractor running a few years ago and I drove it around my yard and in a community parade for fun because it was and always will be my favorite tractor around my yard. I just recently got it running again after 6 years of sitting, all I did was put fresh gas in it, repair the wire from the battery to the fuse box, and turned the key to the ON position and the tractor had power to everything. It cranked right up and ran totally fine didn’t miss a beat, so it runs and drives great. I had to fix the brakes and they work perfectly now, so the tractor runs, drives, and stops, so it can be used a tow vehicle with a garden trailer around the yard and be somewhat of use. However, this is where the real problem is, the Honda 4013 lawn tractor is the entry-level tractor in the 4000 series, with the 4514 and 4518 being the upgraded version of this tractor with bigger engines and more powerful transmissions ( the 4514 and 4518 are basically overbuilt garden tractors) My father gave up on this tractor years ago and bought the old Kohler K series cub cadets to cut the yard with because of the design flaws of the 4013. The Honda 4013 is a vertical shaft 13hp air cooled engine, with a belt drive 5 speed transmission. The PTO Clutch is the same design between the 4013, and the 4514. The 4013 however unlike the 4514 and 4518 is a vertical shaft engine, whereas the 4514 and 4518 are horizontal shaft engines. The PTO clutch on the 4000 series of Honda tractors is very big and bulky (Picture below of full assembly) and the way the engine is mounted in the tractor has a very big impact on how the PTO clutch operates. The whole PTO clutch with pressure plate weighs between 5-10 pounds I tried getting the most accurate measurement as possible, so do not hold my calculations to what factory specs are. The Honda 4514 and 4013 use the same PTO bolt and its an 8x30mm bolt, part number from Honda is 90101-758-000. The problem is that with a 5-10 pound PTO Clutch being mounted vertically on an engine and being spun as fast as 3000rpm from the engine, it puts severe stress on the bolt and causes the threads on the bolt and the crankshaft to strip. However, by mounting the weight of the clutch horizontally like on the 4514 you put all that weight on the crankshaft instead of a bolt with 8mm thread and thus the bolt and crank do not strip out. And to add onto that the Honda 4013 does not have enough crankshaft to mount the clutch completely flat against the bottom of the crank, what I mean by this is that with the actuation mechanism, PTO Clutch and pressure plate, the small 8mm bolt does not screw in enough to mount flatly against the bottom of the crankshaft because the drive pulley to the transmission is directly on top of the PTO Clutch assembly. I measured the distance from the bottom of the drive pulley to the bottom of the crank and you only have 2 1/4 inches of crankshaft to mount a PTO Clutch that is bulky. This is also proven by the fact that the 8mm bolt is stripped out except for about 1/3 of the threads right by the head of the bolt, since their is not enough crankshaft to mount the PTO Clutch assembly flat on the crank, the bolt and crank threads with strip out since the bolt is not long enough to support the weight and centrifugal force of the PTO Clutch. So the 4013 suffers two problems with the PTO Clutch design, first the 8×30 bolt from Honda is to small to support the weight of the clutch vertically, and secondly that there is not enough crankshaft to screw the bolt in flatly against the bottom of the crankshaft because of the engine drive pulley to the transmission, thus not providing enough holding strength for the PTO assembly. Years ago when my father first experienced these problems he talked to local Honda dealers and mechanics in their shops about how to fix this, and they told him that the bolt is not big enough to support the weight and that he would need to drill and tap the crank to a 10mm fine thread bolt. My father also saw multiple Honda 4013’s for sale in dealerships that had the PTO Clutch laying on the floor beneath the tractors. The dealers and mechanics in their shops told him the 4514 is the better design since the weight is on the crank not the bolt since it’s a horizontal shaft engine. But my father was not going to spend 5000$ on a new 4514 when he bought the 4013 new for 1500$. My father was nervous of drilling and tapping the crank, he was fearful of breaking a tap inside the crank, or drilling it the wrong way and ruining the crank, so he dropped the whole project and bought the old cub cadets and fixed them up and we have used them ever since to mow the lawn and tow our cyclone rake in the fall. A lot of people may think this is a lost cause but I think not, this has been a childhood dream of mine to fix this tractor and make it cut grass again after all the years it sat outside in the elements dormant for half of my life . Ever since I found it under a tarp as a 6-year-old and saw the red paint (my favorite color) and remembered riding on it with my father as a 3-4-year-old and seeing how well-manicured the lawn looked like in old pictures of my house, I always wanted to fix it up and make it a running and fully functional machine again. Sorry, if I’m getting very emotion-driven behind this project but this has been a dream of mine for years and I’m so close to finishing it that I can’t stop thinking about it. I wanted to write this post to show anyone who has a 4013 or is knowledgeable about these old Honda’s my process for fixing this wonderful machine back up and making it a functional machine again. And to see if anyone else has had the same problem with this tractor and has fixed it and could give me some advice for this project. As always any thoughts appreciated!

Link to google drive folder for pictures:

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