Thanks, Bill, for the link and the advice. The air filter on my mower is a cyclinder-type that clips on in the front and is connected by a hose. I don't think it's ever gotten any oil on it, but removing it is easy so I tried that w/o success. BTW, my old spark plug was a mess, so I replaced it. But I can see how the condenser and/or points could also be a mess. Ironically, I was in a mower store when a guy with an 18-year-old Craftsman came in to buy (I think) a condenser, probably not the same as mine, but it cost him $40. I'll have to decide if I can replace condenser and points and find out what the parts cost. Cleaning the carburetor sounds like a logical and cheap step, and something I should do anyway. Your manual shows lots of different carbs. I haven't pinned down which exactly I have (my parts list says it's "Carburetor No. 631619"). I don't see a brass nut, but in the exploded parts view in my parts list it looks like a very simple carb. So maybe I can do something with it. In the meantime I went ahead and bought a new mower, a Lawn Boy 10685. But I'm going to hold onto my 30-year-old Craftman, if for no other reason than nostalgia and its excellent lightweight magnesium alloy deck that looks as good as new. Replacing the engine altogether as someone else suggested is also an option, but now that I have a new mower I'm not in a hurry to try that. I've printed out the advice I've gotten here and downloaded that PDF manual. Thanks again!

Heres a Link: http://www.greenbuildingadvisor.com/blogs/dept/musings/saving-energy-manual-j-and-manual-d Even when they do the calculations, the results are usually wrong In his posted comment, Bailes raised an interesting point: the problem of “garbage in, garbage out” (GIGO) Manual J calculations. Several energy experts have commented on the GIGO problem, including John Proctor, Hank Rutkowski, and Allison Bailes. Hank Rutkowski, the mechanical engineer who wrote the original Manual J document, was recently interviewed for a profile posted on the Green Building Talk Web site. The piece notes, “Rutkowski estimates that only 10% of heating and cooling equipment sizing decisions are based on some type of Manual J calculation and that less than 1% of the jobs are based on an aggressive implementation of the recommended design procedures.” Rutkowski explains the GIGO problem this way: “Manual J is a good tool if you use it aggressively. Follow the rules and it will give you a reasonable margin of safety. But the average contractor says, ‘Better safe than sorry,’ so he fudges here and there. He adds 5 to 10 degrees to the summer and winter design temperatures, calls the building ‘average’ instead of ‘tight’ and doesn't take credit for shading by interior blinds and drapes. Then when he finally comes up with a load number for sizing, he throws in an extra half-ton of AC just for the heck of it.” For a high-performance home, sizing by Manual J may still result in oversizing Several years ago, I had a conversation with building scientist Joe Lstiburek about air conditioners installed in Building America homes in Las Vegas. “HVAC designers are committed to the institutional oversizing of air conditioning equipment,” Lstiburek told me. “The average system is sized at 150% to 200% of the requirements of Manual J. They oversize because they don’t know what they will get for a building envelope, and to compensate for duct leakage and inappropriate refrigerant charge. If you size according to Manual J, there is already a fudge factor built in. But most designers then add another fudge factor.” According to Lstiburek, their experience proved the high-performance Building America homes in Las Vegas could have had HVAC systems sized at about 60% of Manual J. To be conservative, his team recommended installing systems sized at 80% of Manual J. Does oversizing matter? There are strong arguments against routine oversizing of HVAC equipment. The best argument is simple: oversized equipment usually costs more than right-sized equipment. Oversized equipment suffers from short cycling. For example, an oversized furnace brings a home up to temperature quickly, and then shuts off. A few minutes later, it comes on again, only to shut off quickly. Many homeowners find the see-saw sound of a short-cycling furnace to be annoying. When air conditioners short cycle, the units don't run long enough to achieve much dehumidification ��" at least in theory. (During the first few minutes of operation, an air conditioner cools a house. But not enough moisture has collected on the cold coil or on the pan below for any water to have actually gone down the drain. When the air conditioner turns off, all of the moisture in the pan and on the coil just re-evaporates.) The conventional wisdom may be wrong, however Increasing evidence shows that energy experts have exaggerated the negative effects of equipment oversizing, however. Studies have confirmed that oversized furnaces don't use any more energy than right-sized furnaces. Moreover, newer modulating or two-speed furnaces operate efficiently under part-load conditions, solving any possible problems from furnace oversizing. Although there are ample reasons to believe that oversized air conditioners are less effective than right-sized equipment at dehumidification, at least one field study was unable to measure any performance improvements or energy savings after replacing an existing oversized air conditioner with a new right-sized unit. The bottom line The main reason to choose right-sized equipment is to avoid paying too much money for equipment you don't need. A Manual J calculation will ensure you don't spend more than necessary for your furnace, boiler, or air conditioner. Moreover, a Manual J calculation will provide room-by-room heat loss and heat-gain information that is essential to good duct design. Without good duct design, you're running the risk of comfort complaints.

The best thing, in my opinion, is to first do a proper heat loss calculation on the house with the new addition. Taco's free FloPro Designer software, along with many other software programs, and even the old Manual-J method will get you your heat loss calculation, and then you can go from there. The old "rule of thumb" methods for calculating boiler size are no longer the way to go. After tightening up the building envelope, installed new windows, caulking gaps, etc. your old boiler might even be oversized... Your boiler is very efficient, and if it shows no signs of failure, and you have it properly maintained, I wouldn't worry about it. I have a Weil-McLain Gold Oil Steam boiler (from 1995) which was converted to hot water when I converted my 3-family from one steam system to three hot water systems. While it is WAY oversized for my 1st floor apartment, I just couldn't part with it. PexSupply.com is a great place to research boilers and find prices and specs. If you decide to have a plumber install the system, insist that they perform a heat loss calculation before selecting a boiler for you. They will usually have a "favorite" brand that they like to install, which might not be the one your looking at. Good Luck, Nick

Well the latest quote is in and it's the best so far. It's for two America Standard Freedom 95, two stage, variable speed furnaces. A 60k BTU system for the rental unit ( it gets a $600 rebate after installation) and a 100kBTU unit ($300 rebate) for the larger upstairs apartment. The quotes include everything; permits, thermostats, hard wired CO detectors, and removal of old oil tanks. 60k BTU cost $5500 100k BTU cost $5900 I will get $900 in rebates so the total cost for the install is $10500 I talked to the contractor as I believed that the units were oversized. The furnaces are purchased from the gas supplier and are the ones approved for rebates. He said a single stage 40k BTU unit will be fine for the rental apartment, but American Standard does not make a 40k BTU two stage unit and the 60k BTU unit will cost the same after the $600 rebate and it will be quieter, cheaper to run and will keep the tenants a bit more comfortable. I could get a 40k BTU Carrier Performance 96, there's a $300k rebate on that. He says an 80k BTU unit would be ok for the upstairs two floor apartment as far as heating goes, but from experience he feels that the larger fan capacity of the 100 kBTU unit is needed to get the air up from the basement to the top floor.