Briggs 300 series engine

Well i was looking at this engine and i was wanting to use it to replace my 18 year old engine that is going to eventually loose the rod. but i was looking at the designs and my engine and the new ones have slight variation, so its basicly the same, but new. I had had my 3.5hp for years, and used it and abused it probably too many times.
but what i like about this engine is, the only thing plastic is the carburetor , and the cam. just like my 18yr old engine.
but these little engines are good engines, they last a long time as you know how to do the preventive maintenance unlike most people.

http://www.briggsandstratton.com/engine_power/engine_details.aspx?pid=11

yeah, if you go by the same design for years on end, it tells ya, that must be a really good thing.
I know they also been slowely getting more ohv engines, and just came out with the direct overhead valve or dov. But im going to wait to get the dov engine cause, that engine cost alot and parts are probably expensive too cause the dov engine hasn't been all over the place yet. even though its been introduced couple years ago, its just not well known yet. but the 300 series is the best engine you could ever buy, not all for the power but for how well it runs and how long it last, when you take care of it.
the only problem that the 300 series has is the diaframe on the carb, it would last longer if they would put a mounting bolt in the center of the carb cause thats were it goes bad. but thats a really easy fix.

also i saw a comment somewhere that said, i just buy the cheapest oil, cause its just a lawnmower, and only used once or twice a week.
even though i don't use them that much, for the break in period i use 30 weight, but i like to use some synthetic, just cause its better than cheap oil.

I dont use cheep oil- ive always used either 30 weight or 10w30/40 and lately ive run 5w20/30 ( cause i had some fressh leftover form a recent change on my truck)- also bot a ton of oil on clearance - all mobil oil that was discontinued real cheep- i change the oil enough so itll be fine.

Ive never thrown a rod or had any motor issues running 'automotive ' oils - as extra insurance i dump some lucas oil additive in when i change it.

In my opinion, if you don't have an oil filter then you are wasting your money on synthetic oil. One of the reasons to change the oil more often is to remove the contaminates, metal flakes, dirt, and grime, from the engine. If you look at the owners manual on most small engines, they call for 30 wt for above 32 degree F and 10W 30 for colder weather.

I run 30wt in everything I have except for my snow blower, which I run 10W30.

Another thing to watch out for with synthetics is that they clean the engine very well, and on older engines this could lead to leaks. Not that the oil is causing damage, just the sludge that has formed from years of service is keeping those gaskets sealed. This may not happen to every motor you have, but it can happen. I would only use synthetic oil on new or freshly rebuilt engines, and also only with engines that have oil filters on them.

well 30 wt allows the engine to slightly wear faster than synthetic. But I have been low on money so this year iv used penzoil 30 wt, better than the cheap crap, and not too expensive at all. and since i have alot of engines i just bought a whole 5 qt jug. Idk when but im going to buy the 300 series mower, but if the engine cost more than the complete mower at walmart i may buy it, more bang for the buck. but hopefully the engine is cheaper cause i really don't like the weedeater brand too much and my snapper deck has a large discharge so it could take on more grass.