Spark magneto jap. Fuel plup, carb needle valve, float adjustment. Valve clearance setting

 

Check the spark plug gap.

My snowblower acted funny and it was junk in the bowl randomly plugging the carb jet. Try draining the bowl and blowing the openings out.

Run one side or the front up on a ramp to get an angle on the engine. If it starts there something floating in the bowl.

The only thing left is the magneto coil to generate spark.

 

Seasonal equipment very often falls victim to a plugged carb. You may have collected a little water in there also if the tank was stored partially full. Could drain the float bowl and tank and try starting it again.

If you dribble a little gas in the venturi and can start it, you will have narrowed it down to fuel issues.

 

Seasonal equipment very often falls victim to a plugged carb. You may have collected a little water in there also if the tank was stored partially full. Could drain the float bowl and tank and try starting it again.

If you dribble a little gas in the venturi and can start it, you will have narrowed it down to fuel issues.

That was my first thoughts, too.
Spark plug gap setting and especially, condensation (water) in the fuel tank.

Check your gap setting with the gap tool.
Drain all fuel, use non-ethanol gas if your manual calls for that. Cycle in the new fuel, be sure to prime the engine if you are able (pulling the starter handle or using the electronic ignition a few times).

 

Can test the ignition, by pulling the plug and resting it against the engine. When you crank it over, you should see it sparking.

 

all that jump starting and cutting off , check the battery and ground . and fuel issues are another good place to look.

 

Thanks for the suggestions... I've got the battery back on the trickle charger for tonight, and tomorrow I'll clean the carb to see if that helps... I do think something might be wrong compression wise with the motor because it's pretty hard to spin the engine by hand but I might be imagining that... it's not like I've spun it by hand much before. If it is the compression out of whack, I'm getting to the end of my small engine knowledge, never tried to mess with that before.

 

tomorrow I'll clean the carb to see if that helps... I do think something might be wrong compression wise with the motor because it's pretty hard to spin the engine by hand but I might be imagining that

If it was running and suddenly stopped it won't be the compression, the valve adjustment. If you can turn it by hand it's not seized. It will be the carb for sure. I have serviced scores of small engines over my years and the typical issue is blocked mainjets, or the little capillary jets that sit in a tube above the main. Or often a blocked airway, sometimes hidden under a plastic bung on Honda engines. You need to strip the carb and blast it out with a can of WD40, only use carb cleaner if you can remove ALL the rubber O-rings because the cleaner will make them swell.

There is so much junk in fuel now even fresh fuel can cause issues. The first thing I do with a new mower is fit an in-line fuel filter if it doesn't have one. I bought a batch of gas once and left some of it in the tanks of a hedger and a blower. It released some muck that looked like thick honey and it fouled the carbs on both. Never skimp on fuel, never buy cheap noname brand and always 95. It's just not worth the drama.

 

Try removing the gas cap. I had one a few years ago that was doing what you describe and it turned out to be the gas cap. I is supposed to vent, but sometimes they stop venting when they get old.
I also have a B&S engine that is at the end of life. I have to readjust the valves every time I want to use it.

I hope your issue is found to be something simple.

 

+1 ^^^^ this. I had same problem, riding mower, did quick search, and gas cap and the vent in it was the easiest to start with at the time. It was also the solution.

 

If you are using regular gas instead of ethanol free you probably have some water in the tank or float. I had very similar problems. I used HEET for years until a friend suggested I switch fuels. Made all the difference in the world.

 

take the spark plug out and turn the motor over to see if gas shoots out . if the gas tank is higher than the carb and the float or electric cur off fails the gas will fill the cylinder and make it hard to turn over . leads back to the carb . was the plug gas soaked when removed ? smell oil for the presents of gas.

 

What does the exhaust smell like? Have a similar problem, only when it gets up to temp, running rich.

 

Look at your spark plug but be very careful of pulling the engine over to check for spark. You can have a flooded engine that will spurt out gas and if the plug sparks every thing gets bright and very hot and smoky.

Just for general info when working on a small engine whether it be lawn mower or generator check for over full oil. The carb will sometimes leak and the fuel will get into the oil. Then when you start it the crankcase vent goes to the carb so the excess fuel and oil gets sucked into the engine. Or if the oil is contaminated with gas as the engine heats up the gas vaporizes and gets sucked into the engine and causes extreme rich running.

 

This has happened to me with all my small engines and we've since switched to an electric mower with great success.

Your carb is gummed up from old gas. Get some carb cleaner and spray a little in the carb throat before you try to starting it; getting some fuel system cleaner and put it into some new gas that you will fill the tank with after you drain all the old gas out. Once it fires and clears the gas line it should run if you carb isn't too gummed up. Unfortunately, most of the newer mowers use a cheap plastic carb that can't be cleaned effectively so you may have a bad carb that won't clean itself. You can try replacing it for about $100 but most of these mowers aren't worth the cost. Your's may be different.

I've learned to empty the gas tank at the end of the year and run the motor until the gas is gone from the line and engine stops from loss of fuel. And buy "pure" gas from a station that sell such a thing without the additives. We started running the pure gas in all the small engines at the farm to prevent thing type of ongoing problem. Good luck.

 

Instead of swatting flies, pull the carb and give it a good cleaning inspection. Mine did the same thing and I just replaced the carb. It's been running fine since then.

 

Agree with @Elessar Death by ethanol.

 

Check all battery connections and ground to frame. Replace fuel line and filter and drain gas into glass container to inspect fuel. You buy a new carburetor for $25.00

 

So… new discovery, I cleaned the carb and when I hook the battery back up it starts smoking where the wires plug into the bottom of the carb bowl. See pic

of the place that is smoking. Did I destroy my carb?

 

Ok, new discoveries, thing smoking is the fuel shutoff solenoid, all it does is shut off the fuel flow when the mower is off, so I just unplugged it. Now when I run the engine with the spark plug out, it spins fine, when I put the plug back it spins a little then floods very quickly and is hard to turn again. What is causing it to flood rapidly???

 

I have only used non ethanol gas in my small engine devices and that stopped ALL my problems.

 

Low oil shutoff? Double check the oil level. Sometimes its the simple stuff.

 

I have been, it's good.

 

Thanks for the thread, lots to learn from.

 

More updates...

I think something is wrong with the valves...

I took the old carb off, I hand spun the engine and it still has a lot of resistance... I think maybe there is still gas in there flooding it so I remove spark plug, engine turns easy now, I used the key/starter to turn it really fast for a bit. Then I put spark plug back on (carb still not there) difficulty to spin returns... now I think something is wrong with the valves. I took the valve cover off, I spun it by hand and one valve goes up and down , then the next goes up and down, then it gets hard to turn for two little bumps, then the cycle starts over and it's easy to turn again until both valves go up and down then it's back to those two spots where it hard to turn the engine again. Any ideas what this could be? The mower did get a pretty big bump when a tire came off it recently, could that have messed up the valves? It happens after both valves go up and down, so is it struggling to get air and or push out exhaust maybe?

 

More updates...

I think something is wrong with the valves...

I took the old carb off, I hand spun the engine and it still has a lot of resistance... I think maybe there is still gas in there flooding it so I remove spark plug, engine turns easy now, I used the key/starter to turn it really fast for a bit. Then I put spark plug back on (carb still not there) difficulty to spin returns... now I think something is wrong with the valves. I took the valve cover off, I spun it by hand and one valve goes up and down , then the next goes up and down, then it gets hard to turn for two little bumps, then the cycle starts over and it's easy to turn again until both valves go up and down then it's back to those two spots where it hard to turn the engine again. Any ideas what this could be? The mower did get a pretty big bump when a tire came off it recently, could that have messed up the valves? It happens after both valves go up and down, so is it struggling to get air and or push out exhaust maybe?

After further research, I'm pretty sure my valves need to be realigned. This nice mechanic has a video about it and he said it causes my exact issue, makes it hard to start:

I'm going to do exactly what he says tomorrow when my feeler gauges get here. I'll also be installing the new carb, I don't think that was my problem to start but it was smoking, probably from over cranking and jumping it etc. The mechanic on the video says you should check the valve spacing about once a year, they get out of spec and make it harder to start the engine. Never heard that before, but it sure seems to be my issue.

 

The engine in your rider has a compression release that helps it start easier.
That could explain some of your issues.
If you’ve been running ethanol gas most often replacing the main jet, and not the whole carb, fixes the running issue.
Jacks Small Engines is my online parts warehouse.

 

It's having compression issues with no carb attached at all, no gas, just air. I expect adjusting the vales will do the trick, hopefully I can do that tomorrow and let you know.

 

To add on Springnook's post, it can be somewhat tricky finding 0 ethanol blend gas. Some of the so called premiums have ethanol blended in. Check online sources to find fuels that are ethanol free.

I do somewhat disagree with his post regarding valve clearance. Had a quad, that was challenging to start at times, particularly in the cold. After doing carb work, I came to suspect valves. Got it going one afternoon without too much trouble. Trailered it out to where I needed to go, and fought with it for a good hour.

Eventually gave up and brought it home. One of the valves was out of adjustment.

 

I think the gas shut off valve is the problem.

 

Mine did that.
What I found was dirt(foreign matter) in the gas tank. Not a large amount but enough that it would allow the engine to start but die almost right away. Especially if I tried to accelerate it.
Took the tank off, cleaned it and installed a new fuel filter.
Problem solved.

 

Problem seems to be solved. I had previously installed a battery shutoff knob, it must have had dirt in it and wasn’t letting full juice to the starter. Removed it and it starts up now. So now it’s running great with a new carb, starter, spark plug, etc. I did adjust the spacing on the rockers too as I mentioned, but that didn’t fix it, it was the battery shutoff knob.