@andyma Looks like my connecting rod won't arrive until some time next week so it may be a while before I can begin to assemble. I am getting more and more frustrated with the lack of information from the manuals and doing searches on Google. I only have one shot of getting this right since there are no replacement engines or shortblocks for this Ariens ST7524 blower. Reviewing everything again I see another potential issue which is confusing. If you look at the manual(figure 33 in original post), it states the marks on the connecting rod must align and face out. Simple enough, but if you look at the oiler assembly in that drawing, the concave side of the oiler is facing up. Now picture in your mind, the flywheel rotation is clockwise, in that direction the oiler would NOT be scooping up the oil as the design indicates, but pushing it to the camshaft side, rather than upwards to the piston cylinder. I hope that someone with experience will reply to this post and hopefully provide an answer before I assemble. You probably have the manual, but if not below is a link that you can download the Tecumseh L Head service manual. I hope it can answer your questions but I doubt it will. http://www.allotment.org.uk/assets/rotovator/Tecumseh-Engine-Manual.pdf

Orange : Not Stubborn at all just knowledgeable within Proper Oil Specifications. You have 13 LB which run ok on Marine Grade Oil then that's all that matters to you . I have run Snowmobiles , Snow-blowers , Chainsaws , Motorcycles , Outboards and Inboards and frequently upgrade my Oil Specifications accordingly to the Best (Better than Suggest Manufacturer Grade). I also repair and rebuilt the above for numerous friends and clients for over 30 yrs. I guess that's why have Chainsaws and Lawnmowers and Snow-blowers that never quit due to improper maintenance or inferior lubrication , because I have seen the results 1st hand.I further understand that the TC-W3 Specs which are Administrated from the NMMA have been recently amended , however that has do with the reduction in dispersant additive within the oil for anti fouling due to moisture intrusion from thermal cycles or leaking seals . It had nothing to due with the adding a detergent to Reduce Carbon which is a Proponent your Marine grade oil will not provide your air-cooled unit. Any amount of carbon 0.40 fouling on a Piston Dome can cause rapid failure . This is why Old Mineral oils required routine Engine Top End De-carbonizing back in the Day . As I said I don't Rely on a Manufacturer who wishs for eventual unit replacement to Guide my Oil Selection . The Oil I use is a little more expensive but I feel it's warranted do to the Application of Use and the Additives Required. You have a right to your opinion but I would suggest you review the Most Recent Oil Specifications Guide on Marine vs Air-Cooled Engine Recommendations and Not Minimum Standards of one Manufacturer . Anyhow Good Luck with your Lawnmowers Bro ! I enjoyed the discussion :)

For anyone looking for manuals for NOMA snowblowers contact https://www.briggsandstratton.ca/na/en_ca/support/contact-us.html choose technical support with ALL the info on the model/serial# sticker, they may be able to send it. they sent me the manuals for my NOMA Grand Prix GP 1028EL Took several weeks to get a reply but they sent the manuals I am happy to share the manuals that I have, Noma GP 1028EL : https://www.mediafire.com/file/zxgxjx4y8waby0i/11437.pdf/file Tecumseh 10hp motor manual : https://www.mediafire.com/file/4ld3lwydnp7yihs/181-639-1+88.pdf/file Hope this helps !

Remember: Check oil on a clean wiped dip-stick! If you just pull it out to check it and don't wipe it and dip it again and pull it out, you'll be seeing the oil that was splashed on it during the previous operation of the engine! Especially if an engine that gets run a lot. As for the plastic gears--i don't worry about that kind of stuff--i figger the engineers that designed the plastic gears were much better educated than me, so they did sell a lot of those engines! An, with proper care, Tecumseh engines will last as long as B&S! A guy gave me a used Tecumseh, 10 h.p. engine, Industrial model, for my older Snapper rider. I put it on and it runs great. Been on it 4 years now, and no problems. I bought a Sears tractor, $25, with a cracked frame, put the B&S engine on my big Snapper Hi-vac rider, and it seems very happy there! Neighbor gave me his tractor--blew the engine on it, i installed a used engine-runs and drives! Do i worry about plastic cam gears?? No--no worry!