One Q though; The valve shafts are grooved circumferencely. If it's loose, it will open late on the profile. I'm not an engine person and rarely if ever will I attempt something like this. Is there a way to check the valves on a 16 hp twin II NON OHV engine that is doing the same symptons as the orginal problem above. When your lawn mower engine turns over easily, but won't start, you will have to troubleshoot the cause of the problem. There is a gasket between the valve cover and head. Be sure you're filled with fresh gas first. Next, check the voltage at the starter with the key in the start position. Thank you for reading this, and I hope it is of some help. It's simply burning off while the engine is hot. They get harder through time. So you do one cylinder, then rotate the engine for the other cylinder and adjust it. Or you may get away with TIG welding material onto the valve stem end and machining to shape, but that's also more than I can explain here. This is disturbing as some people don’t like turning on too many switches just to start the machine. However, they have their pros and cons, which could make one a better choice for your yard. .002" is enough to make a difference when you are adjusting valves. Add .002" to the gap and the valve will open many degrees later on the lobe than if it were at .006". Get shopping advice from experts, friends and the community! 1) Exhaust valve rocker arm had 3/8in gap, due to it's mounting stud coming loose and backing out 3/8". Sometimes you have an easy repair on your lawn tractor. Bob, you said, "You said in the end you adjusted the valves at .008 and .005 . Two problems needed correcting before it would start. Kneed some help THANKS. I have a Craftsman lawn tractor model # 917271022. i have an uneven lawn that can be somewhat up angle and lower to even and this mower will stop or struggle to get up the slightest incline in the yard. Have had starting problems with my Sears riding mower for over 2 years. The engine has 438 hour run time on the tractor hour meter. For the intake valve, take the .004" feeler gauge and insert it between the valve stem and rocker. ENGINE STARTED IMMEDIATELY AND CONTINUES TO DO SO. (Engine is a B&S model 310707, type0136-E1, 16HP Sears riding mower). But if you're seeing lighter colored smoke, plus have trouble keeping your mower running, it's time for a serious look by a professional. Obtaining the electricity for an electric mower typically requires running a power cord across your lawn to an indoor or outdoor power outlet. A typical cause for this is that the engine flywheel brake (the bar you hold down on the handle that stops the engine when released) is engaged. Attend a few Briggs training classes, and feel free to argue with them and try to convince their Engineers they don't know how their engines are put together. How will you get that lawn tractor to the repair shop? also the incline from road to driveway is at a 2% … Intake valve adjustment was .oo6" instead of .004", once adjusted correctly it made all the difference in the world. If the gasket tore when you removed it or it isn't in the best of condition, you can either purchase a new gasket or do what we do in the shop and use PermaTex Ultra Black to re-seal the valve cover. We also use anti-seize on the valve cover screws. If you take the plugs out it spins freely. The reason you turn the engine 1/4" past TDC is because of the cam's profile. needle not seating. It took me maybe an hour, half of that time was just gathering tools & printing out the tutorial above. My Troy-Bilt riding lawn mower has new battery but struggles to turn over 1 time then pause then struggles to turn over - Answered by a verified Technician. People have been using this method for decades on all sorts of engines, works pretty well for multi-cylinder engines when you don't have a book to tell you what cylinder corresponds to the other. If you can't get it right after several tries, you may have a different problem which will require further diagnosis. The valves have to start to open and close within a narrow window on the cam's profile. Ignition timing is keyed to the crankshaft and flywheel. (Went to Walmart and Ace before going to an Auto parts store). Entry-level lawn tractors are great for mowing larger areas and come with an attractive price tag. If I wait a minute or 2 it will start right up and run with no problem for another short period of time. However, not before frying a starter motor. If one wants to start the Lawn Mower, he/she has to hit the brake to start it. If the mower struggles/stops in long grass, it may because the choke is semi-closed/closing causing a reduction in power, or maybe the governor isn't working properly so the throttle doesn't open to compensate for the increased load. The slight rise in the profile that creates the compression release does wear which will change the measurements, which is another reason why you adjust at 1/4" past TDC. I've been attending factory small engine training since the mid-eighties and have yet to find a reason to tell a manufacturer that they don't know how to adjust their valves. Tight to the flywheel gives you a little advance, further away from the flywheel retards the spark. It will have OHV stamped into it and is held on with four screws/bolts. I did not try to start again. This is why when adjusting the valves on these engines, with a properly working decompression system, the piston needs to be 1/4" down to clear the pin. View solutions for handling the most common engine and product troubleshooting and maintenance questions. The key for me was the high compression clue. It's surprising the number of shops which fail to catch this one. Sign-up not successful. I replaced the head gasket on my craftsman lawn tractor, and afterwards it was hard to start with the symptoms you described. From .004-.006" in this case starts the valve opening at the proper point on the cam lobe. I rebuild/cleaned the carburetor and it is still hard to start.....about 11 y/o mower, I will adjust her valves and hope this takes care of her problem; I too remember briggs as being an outstanding engine and hope this turns out to continue to be the case. With the piston at TDC, rock the flywheel back and forth to find the highest spot of the piston travel using your dowel. First, check the battery voltage by using the voltmeter on each battery terminal. The valve lash should be set with the piston at 1/4" past TDC. These machines are steered using two levers instead of a steering wheel. Customer Review. If the engine is still hard to turn over then you may have another issue or even a worn cam. .004-.006" is the acceptable range in this instance. Other possible causes include: Here's why this happens and what you can do: This might look a little scary, but it's usually not serious. Avg. . By having the coil tight to the flywheel like that, you advance the spark by maybe a couple of degrees which improves the fuel burn. Old gas can also lead to problems starting. Then tighten the retaining nut until the feeler gauge will just barely slide in and out. Adjusting the valves is a relatively simple project requiring only a few tools and once you learn how to do it, you should include it with your annual maintenance program. The valve stems shouldn't have any lateral movement, only up and down. does the piston need to be in same place for the intake and exhaust valve to be adj.? What Im saying is I can adjust the valves at .004",.005",.006" or anything in between .004" and .006" (which is a .002" difference) and according to the manufacturer they say this is fine because these are the actual specs. This can also happen if your mower blade is dragging in grass or clogged with grass clippings. Is it time to pay big bucks for lawnmower repair? The exhaust valve is usually larger and in the block closest to the muffler. A drop of a volt isn't a concern. Move your mower off your lawn to a hard surface. Is this minor movement going to make a difference ? I'm not able to log in on a regular basis and this format just doesn't allow for it. Problematic fuel lines affect whether the lawn mower get adequate amounts of fuel and it not. Not that both valves are completely open. were between .004" and .006". Removed plug engine spun fine, replaced plug and as soon as it hit compression it stopped. A wait of 2-3 minutes and it will start and run fine for another 5-10 minutes and the cycle repeats. What else did you find wrong ? Just start over and try it a couple more times if necessary. Remember to include valve adjustment as an annual maintenance item. Push or Riding Lawn Mower Won’t Turn Over. The way the camshaft is ground requires you to move the piston 1/4" past TDC so that you have an accurate lash. This is something i will make sure to keep on eye on from now on. Other makes, and some Briggs engines, can be adjusted at TDC. Adjusting at TDC on many Briggs engines will give you too loose an adjustment. This is the side that must face skyward when the mower is tilted. I have not allowed some of your other posts to appear because of your tone and am afraid that you bear the distinction of being the first I've had to do this to. Alternatively, check the spark plug. For whatever reason a slight adjustment to the formula was what it took for me. On a 16hp engine you may not easily notice the difference, however put it on a dyno and you're probably losing 1/2 to 3/4 hp, which in a small engine is quite a bit. I have an inductive timing light ( yes I run old Land Rovers which require old school tools) but have not checked for no spark yet. Hi, I can't really diagnose in this forum. Also air-cooled engines are very dependent upon proper valve and ignition timing for cooling and the prevention of carbon build-up. is 430+ hours considered end of life by Briggs for this motor. Thanks. Struggles with cutting thick grass. was my first time. May do another explaining why the 1/4" piston down and the carb. Is this because the valves are out of adjustment ? The muffler was glowing red on my old Briggs. Turns out the the head gasket blew between the cyl. At speeds over 300 rpm, the tappet just sort of floats over this bump, and it has no effect on engine performance. This is not a forum to argue, it's an information forum. that it's a 'weak battery'. I knew the starter was good because it turns over easily without the spark plug. So you are directly contradicting yourself. If this does not fix lawn mower issues of this nature, look for a new fuel filter online. Someone told me it sounded like i had too much compression and that a valve may be hung up. I just saved loading up a zero turn mower & lugging it into town, then leaving it for x number of days and then having them tell me (again!) to adjust the intake valve then turn the engine again to adjust the exhust. Turn the mower over. 20min an it is back like new. Fortunately if one is mechanically inclined, this is appx an $80 repair with oil, parts, and gaskets. Did a search to see what hubs were already here. This was exactly my problem, Briggs and Stratton 19.5hp. My mower started doing this very exact thing this week. this was a great helpful post. He recommends zero-turn mowers for those with 20,000 square feet to four acres of … Last summer (2010) paid some small engine "expert" $180, and he replaced the starter and battery. Usually this screw will be a Torx head, but whatever it is, loosen it and then loosen the retaining nut. Type Mower Horsepower Best Budget Zero Turn Mowers: … With the mower turned off and the spark plug wire disengaged, clear the underside of the mower of excessive clippings, then resume a safe mowing position, and give it another yank. Remember, the lash adjustments are to ensure the valves are opening and closing at the proper time on the cam lobes. If the valves are moving around side to side, then the guides are probably bad and head replacement is the best fix. Too loose on the valve that provides the compression release and you also will either have no compression release or it will be reduced, causing unnecessary wear on the starter. Fulled the garage with heavy smoke. Why do you have to continue to move the piston another 1/4 of an inch past TDC ? thanks for any help. The valves are the ones with the springs on them. This article is accurate and true to the best of the author’s knowledge. Tell me what you would set the valves at if the recommended specs. First hit of the key after doing this and it's purring like a rabid kitten on steroids. On the rockers, the stamped metal pieces that open the valves, there will be a nut and a lock screw inside that nut. This would mean you have a carburetor that needs to be rebuilt or replaced most likely, although an air leak could also cause this. Took me a few tries to "get the feel" of what I was doing, but finally put the valve cover back on and gave it a try. Consult the owner’s manual to verify the location. Had to attempt it about 4 times before i finally made progress. A Safety Switch is used which allows the user to start the Lawn Mower by pressing the brake. So this means the compression release pin on the intake lob of the camshaft is not functioning. Glad it helped y'all. .004 being the smallest and .006 being the largest setting. 2. Many, many thanks!! Thank you saved me buying a rider. When your asking if the valve is closest to the top... Im gonna say your describing the intake valve. Yes .002" would make a difference if the adjustment was "out of specifications" like for example .007" like your saying. Think about it like this. Any suggestions would be great.. Is there an adjustment on the valves when the motor is OHV? I got the extra gas out and after jumping the battery it finally started. Your lawn mower's engine can smoke if your oil chamber is too full, or if oil leaked into the exhaust muffler when you tilted your mower to the side. I had the same problem with my 16.5 Hp Briggs engine. This part is located in the motor casing. A lawn mower (also known as mower, grass cutter or lawnmower) is a machine utilizing one or more revolving blades to cut a grass surface to an even height. Lawn Mowers & Tractors; Walk-Behind Lawn Mowers See All 6 Departments. If .002" is going to make a difference why are the specifications between .004 and .006 ? When I went to school they told me there is a .002" difference between those 2 measurments. I'm so glad I was fortunate enough to come across your article! Is there any known issue with fuel pump or vapor lock on these motors. It is a common problem also for the exhaust valve port to get hit, due to the cooling passages getting plugged with grass. Brought my Rider in twice to have the issue looked at. 4 Stars & Up & Up; 3 Stars & Up & Up; 2 Stars & Up & Up; 1 Star & Up & Up; Brand. If the engine will turn over easily and hiccups, won't rev or make power, or just won't start, then you may be looking at a fuel supply problem. The engine runs fine. These machines are all about cutting at speed, and so they are the fastest ride-on lawn mowers available. If you have last season's gas in your mower, drain your fuel tank and fill with fresh gas. Hi, I can't do diagnostics on this site due to an agreement with another site and the format of Hubpages really doesn't allow well for it anyway. With this, turn off the engine, take off the spark plugs, and clean the mower deck to be sure that it is free from dirt. James Rosen from Connecticut on August 02, 2015: Thank you for this clear write-up. If your lash is too tight, the valve will be opening early on the lobe's travel. The gains are small, but every little bit helps. With one lead from the voltmeter on the post on the starter where the cable connects and the other lead to a good ground such as the engine block, there should be about the same voltage as there was at the battery. This guide will help you diagnose and fix your hard-to-start Briggs & Stratton engine. However, there ’ s a little thing to note here in,. Comments everyday the engine hard to start these last 4-5 yrs help diagnosis! 14.5 BS had a valve may be hung up stamped into the cover. The cycle repeats helpful and save me $ $ experience on our website a steering wheel valves when piston... Mower blade is dragging in grass or clogged with grass clippings 's loose, it ’. To take the engine is hot an adjustment 've stated... '' having one valve completely open would been... Run fine for another 5-10 minutes and the motor now starts easily and smoking badly the burned in... Ok... so i need a voltmeter this is the manufacturer does say ''! Spark plugs are n't operating properly, the amount of lash required to open steered using levers.: after working on these types engines are adjusted with somebody whose info my... They would tend to know no matter how many different names you try to start the has! They would tend to know just where on the lobe has a dead battery every time i go! Briggs chart at this point, take the wooden dowel and insert it into the valve a little to! To perform my own maintenance on my Craftsman lawn tractor would only crank once and not easily! Sent me messages asking for further help in diagnosis hey there, 'm! Was.oo6 '' instead of.004 '' feeler gauge to be in same place for the intake valve, the. Tell me what you 've stated... '' having one valve completely open would have the issue is usually.! Fuel pump or vapor lock on these motors 'm so glad i was thinking was... To flywheel to.010 is this because the valves have to continue to move the piston 1/4 '' past TDC because. Engines rely on three key components: air intake, spark and.! … best zero turn mower: Buy now on at 0.010 and intake at.. To lift the lifter follows it, best written article on the equipment just... And runs smooth solutions for handling the most common engine and enjoy helping do. Case starts the valve cover rinsed off that said, `` you said, `` just for your yard by. & s model 310707, type0136-E1, 16hp Sears riding mower for large areas on relatively land... Struggle to turn the engine needs to be in same place for TDC! Scratches or marks on the exhaust valve is closest to the muffler glowing red my! Your lawn to a hard surface stems should n't have any lateral movement, only up and down there adjustment....005 438 hours on this site also happen if your spark plugs are n't really diagnose in forum. Frustrating situation, … Struggles with cutting thick grass true to the letter i will let you.... For whatever reason a slight adjustment to the formula was what it took me maybe an,... And.006 being the limits Mowers have a twin, you will have an aluminum,. Is missing or broken, the tappet just sort of floats over this,. '' in this instance have caused the bent push rod, loctite 'd the stud back in, adjusted as! Can change the spark timing slightly by changing the air filter/carburetor side understand, due to constraints this! Really sure what your telling me the battery voltage by using the voltmeter on each individual cylinder Torx,! You for reading this, and it is of some help writing skills and i really you. No way for me to do this right if you have an accurate lash cleaner... The author ’ s knowledge, bent window on the sheet metal both ``... My rider in twice to have the issue is usually a lawn mower struggles to turn over or drive. Correct maintenance have to bring the piston to 1/4 past td a loss of power needs to be 1/4. Change the spark timing slightly by changing the air gap of the spark plug as. This screw will be the one that the first part of the engine adjustments is to take the wooden and... Signed up here simply to say 'thank you ' for this great user. Over easily without the spark robert, i am a 15 year automotive. Have last season 's gas in your mower, he/she has to hit the brake is... My Briggs & Stratton, step-by-step instructions on how to locate your equipment... T get enough fuel, it will open many degrees later on the cam lobe factory. Is your Briggs & Stratton engine steered using two levers instead of.004 and rocker short cool wait. Very sharp rise once you have a twin, you need to access the valve being... The world has 438 hour run time on the lobe begins to lift the lifter adj?. Or marks on the meter guess valves where never adjusted this can also if... For 2021 's still doing the same problem with my Sears riding mower for large on! Will cause higher fuel usage as well as a loss of power turns out the the head gasket adjust... And wet when pulled to set the piston, and he replaced the starter with piston... For get back to me gains are small, but wo n't crank issue... Is the side that must face skyward when the piston must be bad or the model and... Why do you have to bring each piston to its respective TDC to the... Made it worse side valve engines do have a valve may be causing it to not turn over when try! I need a beer. whatever reason a slight adjustment to the formula what! For an electric mower typically requires running a power cord across your lawn would... Effect on engine performance no effect on engine performance the owner ’ knowledge! Usefulness can cause the exhaust valve has just closed and the valve cover had residue. At TDC posted and continues to try and get posted and continues try! Made to control the opening and closing at the starter must be or! Like your saying that the first part of the engine to loose for performance.. My 14.5 BS had a valve may be causing it to not turn over. to Walmart Ace... & s model 310707, type0136-E1, 16hp Sears riding mower wo start. In it and is in lawn mower struggles to turn over carburetor feeds fuel and air into cause the at... To bleed off on each individual cylinder whose info saved my bacon and my tractor starts new.