Small Engines (Lawn Mowers, etc.): Lawn Mower engine surging, winter storage, walk behind mower

Question
Hi Michael,
I have a John Deere 14st 21 inch walk behind mower with a Kawasaki 5 hp (I think it is a 5hp) engine that is about 10 years old.  I had the carb worked on last year by the local Deere dealer because of surging problems and it worked great after that and the beginning of this year until this week.  BTW...I believe they replaced the diaphram and cleaned the carb.
I was using it this week and it was running fine until I ran out of gas on a hill (cutting it side to side)...I brought it to a flat spot, put some gas in it and started it up...It started surging and has been doing it ever since.  I replaced the spark plug and checked the air filter just in case, but it still surges.  It surges badly at high speed idle and will choke out under load.  I can push the throttle towards choke a little and it will run smoother, but has little power under a load.  My question is...Do you think it is the diaphram again and if so, can they go bad in a year or 2?  I think he told me the other was bad do to age and additives in the gas made it harden.  My 2nd question...Is this something that I could replace myself?  I am fairly mechanical, but don't want to get into a bunch of settings etc since I am not a small engine expert.  Is it something I can take apart and put back together without many adjustments?

If this isn't it, any ideas?  I don't mind taking it to the shop except it will take 2 weeks and the grass is growing rapidly.

Thanks in advance,
Gary

Answer
Hi Gary,

I suspect a weak governer spring.  I would replace that first.  If no better, then most likely there are carb problems again that would require disassembly.  I would look at the float, it's needle and seat.  You could try it on you own, being careful with the parts and the order and location of each.  

I'm not sure what you do for winter storage but I have included my standard proceedure below:

Let me know how you make out.
Michael

Springtime equipment starting problems are very common.

In the fall we all just want to park the mower and forget it.  I do that for a week or so but within a month, usually after the leaves are up I do the storage prep.
I first change the oil.  Old oil has acids and other contaminates, which shouldn't sit in an engine for long periods.  Next, I drain the fuel and put in in the car where it will be used up soon.  Then, fill up the tank with new fuel, fresh from the pump.   (Fuel starts to go bad in one month.  It can either gum up in carb or make deposits, clogging the small openings.)  I add fuel stabilizer.  This is the critical part.  Stabilizer, available at equipment or auto supply shops, will keep fuel stable for up to one year.   (I like the brand "Stabil".) I then run the engine for about 5 minutes to run the fuel through the carb and to coat the engine's internal parts with the fresh oil.  Finally, after the engine cools, I remove the spark plug and squirt about a tablespoon or two of engine oil into the cylinder.   After replacing and tightening the spark plug but not connecting the wire, I slowly crank the engine over several times to coat the cylinder walls with oil.  This step prevents rust and helps to keep the rings from sticking in the piston grooves.   That's it! Ready for winter hibernation!  In the spring, it should fire right up.  After the cylinder oil burns off or after the first use, I then change the spark plug.  I also try to use up all the fuel before adding more.  This proceedure, applies to any engine being stored off season.   At storage time it's also good to do other maintenance as required, like: belts, bearing/bushing lube, blade sharpening, air/oil filters, general inspection, etc. Spare parts on hand make it a snap.