Frustrated with a Cub LT 1018 No Start problem

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Rookiesmom

Forum Newbie
Fellas help a gal out. Y'all are going to laugh at me. I borrowed my neighbors LT1018 to mow my grass it was a little hard to start but would eventually do so. While mowing the steering bushing broke, from age mostly the engine was running fine. I replaced the bushing and could not get it to start. I checked the voltage on the battery which required charging from about 11.7 volts to 12.3 volts ..no problem doing that. Still would not start so I checked the voltage coming out of the starter solenoid, confirmed that when the key was turned the solenoid was getting power ......no joy ..power went in but solenoid was dead, fuse was good...replaced the soleinoid..confirmed 12 volts out of the hot wire to the starter and it was fine. Still no start. Neighbor bought a new starter and because of the way the starter bolts up to the engine housing (and the fact that I didn't have long torx tools) I took off the flywheel.when the flywheel was pulled the timing key fell out sheared. Replaced the timing key. Note that the timing key, though sheared was still in line with the key way when I pulled it so timing should have been fine. I replaced the starter but though now the engine turned rapidly all I could get out of it was a few weak cough's of trying to run for about 5 seconds then...nothing. Gaps on the coils were in spec. Noticed the breather tube was old and cracked. replaced that. Used starting fluid down the intake and nothing, no start. Went to AI GROK and it suggested checking the valve lash. Looked up the specs and reset the valve lash for both cylinders. Yes I have and used feeler gauges. Both intake and exhaust tolerneces were a little loose. Had high hopes that would do it but NOOOO it still would not start. I took the carberator off and checked the needle valve, used carb cleaner on the emulsion tube and used a maybe 24 gage wire to ream said emulsion tubes, cleaned the bowl and checked to make sure the fuel solenoid was working (it was). Put it all back together and though turning beautifully, it would not start. So, though rapidly losing my hair and mind, I put a new fuel filter on it and replaced a couple of 21 year old fuel lines. Cleaned the fuel pump and the screen on the back side of it. The vaccum tube from the valve cover to the fuel pump was fine...no rot or tears, no obstructions. Checked the fuel cap and made sure the vent holes were still good/present. Pulled the plugs after turning it and they were slightly wet so it was getting fuel. I'm Stuck in quicksand here, I know enough about these small engine to do what I have done but not enough to know what else to do or where I have gone wrong. The engine is a B&S Model 40H777, built about 2004 0r 2005. Any suggestions?
 
You need fuel, air, compression and spark(at the right time). In my experience, lack of fuel is the problem a whole lot of the time. You've covered most of the fuel system.

When you were replacing fuel lines, how was the fuel flow? It needs to flow freely from tank to pump. Pull fuel line from carb and crank engine. It should also flow freely.

Have you checked for spark? The light bulb type tester isn't very useful. If you remove the plug, connect the wire, and ground the plug, you should be able to see spark. You need to get out of the sun to see it. If you have another plug, put it in the hole, so it's not blowing fuel out towards that spark you're looking for. You said the plug got wet, how clean is it?
 
Plug is fairly clean not much carbon, gap looks good. Pulled the fuel line off the carb and cranked the engine earlier this week, fuel flow is good.
 
Solid troubleshooting so far. Since it won't fire even on starting fluid, I'd shift focus to spark. Pull a plug, ground it against the block, and crank it. You want a strong blue spark, not a weak orange one.
One thing worth double checking given the sheared timing key. Even after replacing it, make sure the flywheel magnet lines up correctly with the coil. If it's off, spark timing will be wrong and it'll act exactly like this. Cranks fine, maybe a cough, no run.
If spark looks weak or missing, work back through the safety interlocks like the seat switch, PTO, and brake, then the ignition switch terminals. Found this wiring guide helpful for sorting out the start and ignition circuits. https://www.fridayparts.com/blog/ignition-switch-wiring-diagram
 
Rookiesmom said:
Fellas help a gal out. Y'all are going to laugh at me. I borrowed my neighbors LT1018 to mow my grass it was a little hard to start but would eventually do so. While mowing the steering bushing broke, from age mostly the engine was running fine. I replaced the bushing and could not get it to start. I checked the voltage on the battery which required charging from about 11.7 volts to 12.3 volts ..no problem doing that. Still would not start so I checked the voltage coming out of the starter solenoid, confirmed that when the key was turned the solenoid was getting power ......no joy ..power went in but solenoid was dead, fuse was good...replaced the soleinoid..confirmed 12 volts out of the hot wire to the starter and it was fine. Still no start. Neighbor bought a new starter and because of the way the starter bolts up to the engine housing (and the fact that I didn't have long torx tools) I took off the flywheel.when the flywheel was pulled the timing key fell out sheared. Replaced the timing key. Note that the timing key, though sheared was still in line with the key way when I pulled it so timing should have been fine. I replaced the starter but though now the engine turned rapidly all I could get out of it was a few weak cough's of trying to run for about 5 seconds then...nothing. Gaps on the coils were in spec. Noticed the breather tube was old and cracked. replaced that. Used starting fluid down the intake and nothing, no start. Went to AI GROK and it suggested checking the valve lash. Looked up the specs and reset the valve lash for both cylinders. Yes I have and used feeler gauges. Both intake and exhaust tolerneces were a little loose. Had high hopes that would do it but NOOOO it still would not start. I took the carberator off and checked the needle valve, used carb cleaner on the emulsion tube and used a maybe 24 gage wire to ream said emulsion tubes, cleaned the bowl and checked to make sure the fuel solenoid was working (it was). Put it all back together and though turning beautifully, it would not start. So, though rapidly losing my hair and mind, I put a new fuel filter on it and replaced a couple of 21 year old fuel lines. Cleaned the fuel pump and the screen on the back side of it. The vaccum tube from the valve cover to the fuel pump was fine...no rot or tears, no obstructions. Checked the fuel cap and made sure the vent holes were still good/present. Pulled the plugs after turning it and they were slightly wet so it was getting fuel. I'm Stuck in quicksand here, I know enough about these small engine to do what I have done but not enough to know what else to do or where I have gone wrong. The engine is a B&S Model 40H777, built about 2004 0r 2005. Any suggestions?
Click to expand...
Stop. Take some time, do some reading online, think about it. You are jumping from one thing to the next. Ask yourself, what changed from the time the engine was running, until now?
 
The coil(s) may be grounding out for safety reasons if certain conditions are not met. Please post the model and serial number.
 
what brand spark plug and where did you buy them from? Was it a local auto parts store, or online?

Have you checked compression on all cylinders?
 
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