***"BLACK would indicate oil fouling"*** Not necessarily the exclusive deciding factor. The black color only indicates carbon. The source of the carbon will be revealed by other facets of the carbon deposits. Carbon deposits due to lube oil will have a glossy look and will be quite gummy/sticky when scratched. Also the built up deposits can be quite thick and uniformly cover everything about the spark plug completely. Carbon deposits due to a very rich fuel mixture are sooty and powdery looking, and when scratched, will readily shed dryish flakes or specks. Often, where a rich mix is causing carbon, you might see places on the spark plug where the carbon has already flaked off or areas where the carbon seems not to be as thick. A poor boy's method for testing/guessing at compression issues can be done using compressed air. If using this technique, you will need both valve covers removed. You will need an adapter fitting that threads into the spark plug hole and accepts to being fitted to a shop air hose. The engine must be rolled to the correct position (piston 1/4" down and beyond TDC point of the COMPRESSION stroke) for the cylinder being checked. The engine absolutely MUST BE HELD FROM TURNING by some means to prevent the piston from reacting to the compressed air. You would have to figure out how to hold it with what you have on hand. An alternative method that does not require engine to be "locked" is described at the end of this description, so read carefully not to get the 2 confused. Air pressure needs to be 90 PSI to 120 PSI for best results. The air hose and all fittings need to be free of leaks as you will be "listening for leakage" in the test (and any air leaks in the plumbing can dull your testing accuracy). Each cylinder must be tested individually and the piston for each cylinder must be in the correct point, which means you will have to go through the locking and unlocking of the holding device for each cylinder. Once the engine is rigged against turning, apply compressed air to the cylinder you are testing. Now, you must listen carefully for air leakage. I use a 3 foot length of 3/8" plastic tubing to pin point the leaking spot/area by using it like an impromptu stethoscope. Hold one end of the tubing near to one of your ears (but don't stick it in your ear) and probe the following places on the engine with the other end of the tube: Get inside the valve push rod area of the cylinder head where the head meets the block. If the head gasket is leaking, that is where the leak will be. If you hear air leaking, and it gets louder as you probe nearer to the head/block juncture, and begins to become quieter when the probe goes deeper into the gallery (has moved past the head/block juncture), you have located the leak. But.....if the noise level continues to increase the deeper into the gallery the probe goes.............the leak may be coming from the opposite cylinder head or rings. So you have to test BOTH cylinders the same way, but one at a time. If you find that escaping air noise heard through the plastic tube increases on BOTH cylinders the deeper into the galleries the probe is inserted, and you do not hear an obviously louder sound when the probe tube end is positioned right next to either head/block juncture seam.......... the air is escaping past piston rings. This test method will also identify valve leakage by placing the probe tube into the exhaust/muffler or the intake/carb locations. There is also an alternative to rigging a holding fixture to keep the engine from moving under the influence of the compressed air. The alternative way is to REMOVE the push rods from the rocker arms of the cylinder you are testing and simply place the piston at BOTTOM DEAD CENTER (BDC). With the push rods removed, the terms compression, power, exhaust, and intake stroke become meaningless, as both valves are closed. The push rods must be marked so as to get them back exactly where they came from. It only requires finger tip pressure to push the valve spring down to remove the push rods. My thoughts on the Vanguards having "head gasket issues" are that the "true Vanguards" (and the 303700 is a true Vanguard) do not have any ill repute for head gasket failure. On the other hand, the Briggs single cylinder OHV 280000 and 310000 engines DO HAVE somewhat a reputation for head gasket blow out. Same goes for the Briggs V twin OHV engines that are just based on having one more cylinder of the same design as the 28 and 31 OHV Intek family (405700 and 445700). This post was edited by mownie on Tue, Feb 4, 14 at 12:02

I can give you some input based upon my experience with the engine (16 hp Kohler single) and tranny (K51) that is in my 2000 Scotts 1642. These are the same engines and transmissions used in the LT155 and LT160s that year. I have approx. 300 hours on my tractor. The enging and tranny have been flawless. My tractor has a 42" deck, but again, comparing it to the 42" deck available on the LT155 and LT160 that year, they are nearly identical. My unit has not lead a particularly easy life. I pull a 40" Brinly core aerator around behind it with 125 lbs of extra weight twice a year. I mow approx 3/4 of an acre with some hills. If the tranny and engine on the LT150 feel strong I wouldn't worry about them failing or being the weak points in those tractors. BUT, without knowing the hours or how they were used (or abused) by the previous owners, I would buy the new one. You get a warranty and from the description of how you plan to use it, it should last for the rest of your life. The Deere LT's were good machines. I wanted one but they were about a $1000 more than the Scotts units at the time and I couldn't afford the jump. It turns out these early JD Scotts units were pretty good machines and based on how it has performed up to this point, I would expect another 7 years out of it without any major problems. Good luck in your decision.

The entire Briggs theory is apathy, same as a Craftsman Tractor. The thinking is that most people don't pay much for Briggs powered equipment, so it doesn't see any maintenance, and for the most part is abused; e.g. left outside all winter, no storage, fuel contamination and so on and it is really a shame to see what shops are quoting for repairs when they can get to them in September! Two cases in point just today: Two Craftsman tractors, a 1000 and a 2000 series. The 2000 I started in on first, a two-year old machine which would only run with the choke on last fall was subjected to outdoor storage, on Cape Cod with the crazy wind and driving rain all Winter. Long story short, with a crankcase full of water, the #2 connecting rod in the 20 HP Briggs I/C Plus broke. What a shame. It now has a 14 hp Kohler Command sitting between the frame rails, thanks to Craigs list. The 1000 is not so fortunate. The 14.5 hp Briggs Intek had no air air filer housing on it, and is packed full of water. No worries, I/m not an Intek fan anyway. Thanks again to eBay motors, a local pickup on a Vanguard twin was made and once again these nice machines will mow acreage. Flip these machines over and they are pretty much the same underneath. Sure some have a cast front axle and electric PTO's however they share the same powerplants and transaxles. My personal mower? A Deere (later model ) 317 with a Kohler and a hydro rear mounted tiller. Have a great one!

I'm not sure what the cross reference filter's part number was. It was just one that crossed and that was in stock. The outer diameter was 1/4" smaller than the B&S filter. Concerning the sequence of events - the clogged filter resulted in fouled plugs. I wasn't aware that the plugs were fouled but I did know that the filter was tremendously dirty so I changed it but didn't change the plugs until after I realized that the filter change had no effect. Once I noticed that the plugs were fouled I changed them and the mower seemed to be working properly but it then fouled the new plugs in after only running it for 1.5 hours. I went to the B&S website and submitted the information to them to see if they had any recommendations and their reply was to change the air filter. I wrote back and told them that I had already changed it but it didn't make a difference. The tech then wrote back and asked for the model number of my engine and when I provided that to him he responded by telling me that it was a documented problem with that engine and that there are several cross reference filters that will fit but the mower won't run well with. Twice he wrote to me and told me to change the filter to the B&S numbers and it would fix the problem. Obviously I had to change the plugs too since they were fouled and when I did that this weekend I could immediately tell that it was running much better. I used it for ~3.5 hours and it never missed a beat and I could tell too that it was no longer running rich. I'm sure it is fixed because even when it seemed to be running well when I had changed the plugs the first time it still ran rich. This time there were no signs of it running rich and it never once lacked power or backfired as it had before. The part number recommended by B&S is: Air filter 692519, pre filter 692520. BTW, the tech also stated that there are even hood stickers that call out the wrong air filter part number too. The printed material that I have for my engine even lists the wrong spark plug gap. I found that out when I had the tech verify all the numbers and specs for me before working on it this weekend. Lastly, the salesman at the parts store told me that they had experienced problems with that same engine when they had used other air filters. As he stated it, "that motor is very picky about the air filter that it uses". Strange but true! At least in this case. Thanks again. Scott