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HELLO, i have a 7 year old l180 has the 18.5 hp intec briggs ohv-- all of a sudden- it starts hard-- but when it starts- runs fine- i go about 10 minutes- it quits and won`t start-- i was wondering about that gas shut off soliniod attached to the float bowl? this thing has olny about 100 hours on it and it looks new- i kind of read up on the valve adjustment deal- so i will be doing that- but it should`nt quit after it starts? thank-you for any suggestions
 

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Based on your description of symptoms, I wouldn't be inclined to replace the solenoid. I gather from what you wrote that it was running fine up until recently. So, the current problems came on sudden like. Like sitting for a few weeks between running and then the problems begin. Can you say "bacterial buildup" on the filter or tank? I've seen it. Weird symptoms but could be your problem. Okay, maybe not, so let's take a normal approach to the problem.

Assuming your battery's good and swings the engine okay, then there are the three main systems to check. Standard troubleshooting says you need fuel, air & spark to run. Air is rarely a sudden problem. Engine just looses power over a long period until the owner cleans out the birds nest from the air box, so we'll not look there first. That leaves fuel and spark. While spark may be the problem (weak, intermittent) it would be good to first eliminate MOST of the fuel section, then go back to the spark. Let's do the fuel first.

Pull the outlet hose off the fuel pump and attach a short piece of hose. Place the end of this hose in a clean container. Now, crank the engine and look for a pulse of fuel for every rotation of the engine. If nothing comes out, you probably have a blockage (fuel filter, hose muck, grass in the tank outlet, etc.) or a defective fuel pump. Either one can occasionally let enough fuel through to start but will crap out under load. Pull the inlet side off the pump and lower below tank level. If fuel comes out, the pump is suspect. If it's still not flowing then you have a full/partial blockage. Fix that problem (new filter, blow back through line, etc.) and try again from the top.

OK, fuels good so let's look at spark. On older engines we'd look at the points first, but yours is an Intek and that's probably a solid state module. That MAY be subject to failure once it heats up. Not sure how to troubleshoot that except to carry a spare plug with you and test your ignition system when it fails on you. Disconnect plug lead from engine and connect to your spare plug. Ground the body of the plug and crank the engine like you're trying to start it. You should see a spark (may need to be in shade, out of direct sunlight). No spark, then bad module/coil/wire or some other gremlin in the ignition system. Good spark, then we'll move on the the carb.

You mentioned that it runs fine once it starts, then quits after ~10 minutes. Doesn't sound like carb, but they can be tough to troubleshoot. The solenoid is a binary part. It either works or doesn't. If it pulls the pin out of the way to allow fuel to flow to start, it'll probably stay that way until you shut it off. It's also a hysteresis effect part. It takes more current to pull it in than it does to keep it pulled in, so, if it works at startup, it probably won't drop out unless your battery drops way low in voltage. And, it won't start to run bad, then die. It'll just die, period! So, about all you can do to troubleshoot the solenoid is see if it clicks when you turn the ignition to the run position. You can even feel the body to sense the clicking of the unit. If it clicks, but the engine still doesn't start/run you can probably discount it as the problem source.

That leaves dirt/blockage in the carb proper. No way to check this from the outside and not a trivial task for the uninitiated. But, if you want/need to, then remove and disassemble the carb and clean/soak to remove debris. Check float level and inspect for any obvious damage. If you have enough dirt reserve in the bowl to cause your problems, then it'll be obvious when you pull it apart. You have been changing the fuel filter on a regular basis, right? If not, do it now.

Since this is mid-season, grit probably isn't the problem. It would have showed up in spring at the first startup. Carbs left with fuel in them and allowed to dry out over the winter or long storage can build up grit in the passages. When you see it, it's like a hard sand deposit that breaks apart when you pick at it. That's why there are two schools of though on storage. Either drain it and run it dry, or let it have gas in it all winter. Either way, the fuel doesn't evaporate to dryness and let the deposits behind. If you find yourself with sand in the carb, only a soaking in HydroSeal or equivalent will work. Time to get an experienced mechanic involved or be aware of the hazards.

Now, there are myriad other sources of failure for your problem and I'm just citing the obvious ones. Others may chime in with more. I also liberally use the terms "usually, probably, may and might" because troubleshooting is never an exact science. First, isolate the system that's causing the problem, then divide that system in the middle and work toward the problem. A a good dose of experience helps a lot!

HTH,
Paul

Standard Disclaimer: I'm not responsible for you setting fire to your mower, your house or yourself. I'm also not responsible for you getting a good dose of electricity from holding a live spark plug, arcing across your starter leads or swallowing a mouthful of fuel. :( Common sense and caution applies herein. Proceed with caution and THINK AHEAD!
 
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