[RocktimusPryme]

Originally Posted by poncho-mike

Who makes the engine? Is it Kawasaki?

I can't speak to Toro models, but you mentioned the vacuum fuel pump wasn't sucking. Have you checked your fuel cap? I have a 27HP Kohlen engine on my Craftsman garden tractor. It has a vacuum operated fuel pump. As the engine sucks fuel out of the tank, air needs to get into the tank to replace the gas that the engine drew out. If the gas cap vent is stopped up, it will start to run into issues. Try loosening the cap and see what happens.

That’s a good thought but I’m saying the port at the intake manifold actually isn’t making any vacuum while cranking. I took the pump out of the equation and checked vacuum signal at the source.

[mgarblik]

The engine on your Toro is most likely an LCT engine. Liquid Combustion Technology Inc. and CPC Certified Parts Corp. purchased the assets of Tecumseh at least 10 years ago. Both Chinese companies, they produce primarily private label engines for equipment manufacturers at a discount vs well known name brand engines like Kohler, Kawasaki, Briggs and Stratton. This doesn't help your problem however. My guess is the valves are bent slightly and not seating well enough to make power like it used to. You could remove the heads and at least check that out. Put the valves in a drill chuck and see if they are visibly bent. If they are OK, lap them in with compound and put them back together. With only 2 cylinders, you have to have good valve seal to run decent. I owned a small engine shop decades ago and old, stale gas and burned valves were among the main things we saw on a daily basis. Good luck with it.

[Jack Gifford]

Originally Posted by RocktimusPryme

... the port at the intake manifold actually isn’t making any vacuum while cranking...

I suspect that the vacuum operated pumps typically don't pull measurable vacuum while cranking. They depend on the engine starting with fuel already in the float bowl.

[VCho455]

I'm with Sarg. Sometimes it's not worth fixing.

[Sirrotica]

Check for tight valve guides, or varnish on the valve stems.

One year I parked my lawn tractor in the fall, and it ran fine; after setting all winter I went to start it up and one cylinder was dead. The valve stem had varnished up from sitting. The valve moved a little bit, but it was being held off of the seat by varnish.

One would think that removing the spring and spraying the stem with carb cleaner would dissolve the varnish. Well after about an hour of spraying and fighting with the valve I finally got the varnish off enough so that the valve would seat. In all my 5 decades of working on engines I have never seen a valve stuck that badly. I've never seen it happen since that time.

The relatively weak valve springs would never overcome how badly that varnish had that valve stuck. That was about 15 years ago, the engine ran fine until the deck finally rusted out. I still have the tractor, likely the engine is still in good shape.

Just one freak thing I ran into over the years, maybe it's not your problem, but at least something to consider looking at.

BTW, my neighbor owns a lawn care service and runs Toro commercial equipment. He told me that everyone he knew that purchased mowers with that proprietary engine has had tons of trouble with them. The new Kohlers are supposed to be problematic also. All his mowers have Kawasaki engines on them with tons of hours on them. little to no downtime. Last zero turn I bought I also went with a Kawasaki.

Good luck solving the problem......