Sign in. A 4 stroke engine has separate inlet and exhaust manifolds so it can be easily turbocharged. Share this conversation . The few times it has actually cranked gas flows out of the muffler and drowns the spark plugs. #3. this may be a little excessive, but if it's not blowing back. Show More. Page 5 of 6 - Blow back through the carb on 314 - posted in John Deere Tractor Forum: If you still get the symptoms you were before after the timing change.. CCW ls the K-series rotation.. i can't see that going well Jun 18, 2012 #10. I have only once in my life experienced air being the problem with a 2 stroke engine not starting. Page 1 of 2 - Spitting Back Through The Carb - posted in Problems, Questions and Technical: Morning! I've got a Briggs and Stratton 11 HP L head (horizontal) on a mower I'm trying to fix. Spray starter fluid into the carburetor. Carburetor choke: Choke Lever down if engine is cold, if hot; choke lever up. It might have been doing this before also, but I had the air filter on and wouldn't have noticed. A two-stroke engine makes power every 360 degrees of rotation. Engine oil that becomes excessively old and worn will leave deposits in the engine oil passages over time that can build up and create bigger problems. Check spark plug; Replace if black and worn electrode is found. You can sign in to vote the answer. Ray. I took the breather off and tried to crank it and gas is blowing out the back of the carb through the choke assembly. My boat engine. Pull on the starter rope. I have an briggs n stratton 31A607 It is blowing air back through the carborator instead of sucking any suggestions? I almost mentioned it.. (It did occur to me..) Oh well.. But the fix is simple grab the pipe with pliers and pull it back to round. A simple way to test this out would be to add a slight extension on a carb with an engine that spits back fuel. If no start go to step #3. Iv got a little problem with my 1.5 riley rma. As the oil passages become clogged it becomes difficult for oil to drain from the top of the engine down into the crankcase, cause oil to build up and pool inside the top of the cylinder head. Now I know its not a mini but an engine is an engine and the basics are all the same which is why I posted here. The breather has a one-way flapper valve that should relieve crankcase pressure on the piston's down stroke, then seal on the upstroke, causing vacuum to suck the oil back into the crankcase through the two small holes at the bottom corners. You can follow any responses to this entry through RSS 2.0. Happy Trails. Typically just a visual inspection of the air filter and carburetor area is all it takes. If it ain't broke don't fix. No Engine Start #1. Replacing the needle valve mechanism is the trickiest step when reassembling the Ryobi 2-stroke engine carburetor that we use for demonstration in this article. 2 Stroke Engine Troubleshooting - Air. compression check, all cylinders @ 150. ignition off. How do you think about the answers? Here are some things to look for while you're searching for the source of the issue: Too much oil in the crankcase (overfilled!) For inducted air-fuel mix engines the maximum compression ratio is limited by the octane rating of the fuel. through the carb should be ok. 0 1. Mechanic's Assistant: Has the vehicle turned into a gas hog? #2. You will get a quick, accurate, answer and I don’t charge a dime! Going insane! 0 0. When the piston moves up, a vacuum is created in the crankcase which is connected to the carburetor. Technician: cameronsmallengines, Small Engine Tech replied 9 years ago. When I check the valve clearance at 1/4" past TDC I have the correct clearance .007 (aluminum block), however, during the ENTIRE compression stroke, the intake valve is open a few hundreths and it's blowing the fuel out of the carb. 3. Answered in 56 minutes by: 6/11/2011. Engines in older cars and other gas-powered vehicles also had a carburetor before the introduction of fuel injection in the 1980s. Turning/tilting the engine on its side for storage, oil change or any other reason. This is normal and all two stroke engines do it, think of it as part of warm up. This entry was posted on January 18, 2010, 9:02 am and is filed under ATV, Motorcycle, Snowmobile. Rebuilt the engine and it started and all seemed well apart from the engine smoking a little (which I put down to it burning off the oil used in the cylinder / crank during the rebuild). When the piston goes down, pressure is created in the crankcase. Category: Small Engine. Note: If the engine has to be tilted, ensure the spark plug is facing upwards to help prevent oil from escaping the crankcase. White608 Go faster Established Member. When spraying into the needle valve hole (where #19 goes) and the idler jet hole (14) spray from the bottom of the carb back … When a 4 stroke engine is converted to 2 stroke, the cylinders are used at twice the rate, so it has an improved power to weight ratio, but with higher emissions. Does not start because it is blowing gas and air out the carb. chevy 350 is blowing air and fuel back thru carb when cranking. This definitely indicates a new top-end is required, as well as a new spark plug. Mark is here to walk you through the steps needed when diagnosing your two-cycle engine issues. Finally, sparing many details, 2 strokes operate using pressure differentials between the intake and cylinder (on the intake stroke) and the cylinder and exhaust pipe (on the exhaust stroke) to generate mass flow. Troubleshooting A Crankcase Breather That Is Blowing Oil: If your crankcase breather is passing oil, chances are that something's wrong (Okay, we know something's wrong, but don't be too alarmed). Just the carburetors! Somehow the 2 stroke engine on my strimmer is backfiring when i start it, i pull the handle, it turns over and fires three or four times then something goes wrong and it starts flamethrowing, it does this all the way upp to 75% throttle and as soon as i lift my finger off the trigger it makes a huge explosion and stops dead. 1)I've never seen a 2 stroke carbureted turbo sled. It's called a two-stoke engine because there is a compression stroke and then a combustion stroke. Checking to make sure your engine is getting air is the easiest part. As for terminology, dwell is the wrong term to use for the difference in exhaust/transfer port timings. A problem which plaged the 3 cylinder Evinrudes. Suck-Squeeze-Bang-Blow The two-stroke snowmobile engine is, mechanically, very simple, but how it breathes is rather complicated. Place the needle on the lever. two stroke engines need some back pressure, to run efficient. Air/fuel is then sucked into the crankcase. All two-stroke engines on trimmers (and also four-stroke engines on lawn mowers, generators, and other small equipment) are fitted with a device called a carburetor (often shortened to carb in North America or carby in Australia). This carburetor's needle valve lever has a forked portion on it. Back in the days when pistons were uniformly poor and two-stroke engines wouldn't be run very fast, wrist pin bearings were almost always a simple brass bushing. Anonymous. This vacuum opens the reed valve and sucks air/fuel/oil in from the carburetor. When I accelerate I find it spits back though the carburetor. Jun 18, 2012 #9. 2. Page 3 of 6 - Blow back through the carb on 314 - posted in John Deere Tractor Forum: If you clean the valves up and re-gap and it still dies it, The cam has ACR.. Show Less. Possible flooded engine: Try starting with throttle wide open. Joined: Aug 24, 2011 Location: Valley. Two stroke engines do not have intake or exhaust valves as in four stroke engines. 1 decade ago. Now pull the starter rope and see if your engine starts up. Put it back on, and now it doesn't die right away when I accelerate with the choke open, but what it does do is sputter and shoot a gas-air mist out of the carb's air intake! Checked the plug, a bit of carbon on it, nothing special. The carburetor is the main component responsible for metering and delivering the air fuel mixture required for the engine to run. Is the valve working properly? Then, put good, fresh fuel in it (properly mixed with a quality brand of 2 stroke oil) and just run it. I have a Briggs model 407577 Type 0292 E1 21HP Intek V Twin engine that is blowing gas out of the carb and flooding the engine. The breather can be removed for inspection of the back side. Submitted: 9 years ago. Sometimes the spring takes a hiatus and it wont stay in the correct position @ WOT.. Messages: 352. Internal problems that cause oil to leak through a lawnmower's air filter typically require repair by a small-engine specialist. Then take your can of WD 40 and using the plastic hose that comes with it spray the WD 40 into all of the holes. Ask Your Own Small Engine Question. cameronsmallengines, Small Engine … Spray a little bit of starter fluid or carburetor cleaner directly into the air intake on the carburetor. In a 2 stroke 70H.P Veinrude, the spitting of fuel back through the carb can be caused by excessive fuel - a carb problem- and/or a reed valve problem. After about 4 miles, the engine was starting to ‘bog’ and then mis-fire. So the question. I have personally seen a CR80 that fouled plugs because of a bad top-end. I mean without auxiliary injectors or other electronic stuff. And how does it start -- same as usual? If you have any questions for me, please ask. Once cleaned used compressed air and blow through all of the orifices. Lv 7. Here are the steps for replacing the needle valve mechanism: 1. desert camel. Other reasons for blue or white smoke from engines include: Exceeding the engine’s oil capacity shown on dipstick. Running the piss out of it will "clean it out" for you. A four-stroke engine separates the intake, compression, power and exhaust strokes with the use of poppet valves, but it only makes one power stroke every 720 degrees of rotation of the crankshaft. 2 strokes differ from 4 strokes because a piston cannot push exhaust from the cylinder when back pressure is high. Once the piston makes it to the end of the compression stroke, the spark plug fires again to repeat the cycle. If the jetting is right, a fouled spark plug can also be caused by a bad top-end or blow-by from the worn piston/ring/cylinder. "Air" is usually never the problem. Best thing to do is go through the carb and make sure it's clean. It can also be an early indicator of engine failure.... compression leaking by rings that are failing and are gouging the cylinder wall. Hi, I'm new on the sled scene, I don't have experience but I'm very interested in the twin carbureted 2 stroke sleds.