Absolutely you should only use the 2-cycle mower for this. There have only been offered very few 4-cycle mowers with oil pumps, and these are the only 4-cycle mowers that are safe to use on steep inclines. Since your 4-cycle is splash lubrication, it is not suitable.

I don't believe there is a 4 cycle engine made that is recommended for that kind of slope. The 2 cycle doesn't care as long as the carb works.

Now for a myth. So called splash engines running at operating speed will run on every bit as much angle as a pressure lubed one. Where do you think a pressure lubed engine gets it oil? Do you think it comes from some mysterious oil reservoir? No it comes from the oil sump just like the "splash" ones. When the oil pick up is out of the oil, you are out of oil just like the splash. IF you will check, Splash or "slinger"systems which applies to most direct oil at such volume and velocity that an incline has no affect on them AND usually, they draw oil from a point lower than oil pump engines as they normally have a well they draw oil from which has higher sides around the well.

Walt Conner

@Saxman, I'm not the only person in town with the same issue. Some folks plant ground cover, as you suggest. I even saw one guy who has more like a 60 degree slope lower a lawnmower on a rope down the slope in multiple swaths all the way down his lawn.
I actually prefer it the way it is now to when it was covered with brush. It was a constant struggle to keep the brush from encroaching onto the yard, the brambles in particular. Cutting grass is not typically thought of as dangerous, but I would get bloodied by stray blackberry and rose branches every week.
We have thought about landscaping the area, but the amount of maintenance to keep it looking reasonable would be worse than what I am doing now.

The "IDEAL" mower for this application would be any of the Lawnboy Aluminum deck self-propelled models made before they discontinued the 2-cycle engine. Now there have been other brands of 2-cycle mowers, but NONE have the following and parts availability of the good old Lawnboy mowers.

This post was edited by phototone on Fri, Sep 19, 14 at 11:51

I hear ya, phototone - a lighter mower would be preferable. Both mowers are Snappers with heavy steel decks. The carb jet clogged a couple of weeks ago, and I had to walk the thing up the 45 degree incline and then up the gentler (maybe 15 degree) slope back to the garage. Of course this happened at the furthest point of the yard from my garage......

Two cycle is the way to go. I understand you can sometimes find them on Craigslist or at a dealer repair shop that services them. The only other option is 4 cycle mower with oil injected engine, but most of these are professional models and are pretty pricey (over $1000). They're also more complicated and costly to repair. Two cycles are worth fixing. I've had two at one time. One gave up the ghost after plying through a foot of leaves in my father-in-law's gigantic yard. It was repairable and I wish now that I had kept it. If you have hilly terrain, it's the only way to go. Mixing the oil and gas is a breeze and you just run it out for winter storage. Fortunately I still have an older model from '94 (apparently that model was more durable than the Duraforce) that is still beating. It's a workhorse and like an old friend.

I was wondering the same thing too as I need to do some field mowing. There are both flats (mostly) and some slopes that are well over 15% that join the slopes. Likely takes 10 - 15 second to transition up or down the slopes. I was thinking I would just tank up with a mixed gas for that job. Yes it might smoke a little more or might foul the plug some but it would be the best of both worlds with a four cycle engine. I also thought about an engine additive like Lucas oil. It is on display where it shows that it "clings" to the engine parts to keep them lubricated. Has an one tried it?

No, I do not suggest that.

If you could locate one of the old Tecumseh Diaphragm Carburetors that would make a great mod for a 2 cycle carburetor on hills.

Maybe they never did it was it would run upside down also.

"I was thinking I would just tank up with a mixed gas for that job. Yes it might smoke a little more or might foul the plug some but it would be the best of both worlds with a four cycle engine. I also thought about an engine additive like Lucas oil. It is on display where it shows that it "clings" to the engine parts to keep them lubricated. Has an one tried it?"

You completely misunderstand the 2-cycle lubrication principle. Mixing oil in a 4 cycle engine will only make it smoke and carbon up - do no good at all as far as lubrication on a slope.

Walt Conner

A 4-cycle engine draws gas directly thru the intake valve into the cylinder, no amount of oil in this gas will lubricate the bearings. A typical 2-cycle engine, as on most lawnboy mowers and most string trimmers, chain saws and the like, draw the fuel-oil mix thru the crankcase, where the fuel mist deposits oil on all the moving parts on its way to the cylinder. You can see the difference here.

Thanks Walt I was thinking that it would lubricate the vales at the top, not the bearings at the bottom, so yeah you are right... As for the Lucas Oil it is an oil additive that goes directly into the crank case, not into the Gas. It has a "trade secret" lube additive.