1811 missing a beat

[yeeter]

Plenty of snow duty over the weekend, which made use of every machine at my disposal. It was fun for a few of the hours.....

BUT - the 1811 started missing. Its very noticeable when both sides kick in/out. This has been my regular 'goto' tractor and not the best time of year to act up.

Since one side goes fine I was thinking unlikely to be fuel related (can one side be starved while the other side runs fine??). I know the fuel lines are starting to deteriorate in/around the carburetor.

I thought I would start by simply pulling the plug and inspecting. Heck, I should just replace them both while at.

But thinking I should start with spark.

A new troubleshooting problem for me, so any advice welcome.

[J-Mech]

Unless you've run it on a scope, don't assume that the miss is only on one side. Sitting in the seat, you would know if your losing one cylinder, or both intermittently. I'd star with ignition. Fuel doesn't usually cause random missfires..... unless its water in the fuel. Then it could.

[yeeter]

Originally Posted by J-Mech

unless its water in the fuel. Then it could.

Thanks Jonathan. I have certainly had problems with the fuel before. Maybe some fresh fuel is a simple starting point (or at least another piece to check/eliminate).

Its changing modes for minutes at a time (say, 30sec to a couple minutes). So if not related to just one cylinder as you say, fuel problems maybe still on the table. And its been pretty cold here (teens) although its happening even after the engine is warmed up.

Stay tuned, I wont get to troubleshoot this until later this eve or tomorrow.... Will start with electrical and keep the fuel on the suspicious list.

I have an old timing light that clips on a spark plug wire, could see if that triggers as a starting point.

[J-Mech]

I suggest pulling the carb and draining the bowl. I don't know what it is about the mag18's but I have to do that to mine every 100 hrs or so. Only tractor I have trouble with, but water seems to collect in the carb.

At this point, im not going to sway to fuel or ignition. It's more that likely ignition.... but i know those mag engines really well and a little water in the fuel bowl will give them an intermittent miss.

[inspectorudy]

If it was my 1811 I would pull the plugs first since that is the easiest thing to do. I always do what is easier first since I am lazy. A fouled plug is readily identifiable and if that is the issue you are good to go. I am curious how you have determined that it is only on one side though. If its on both then it almost has to be fuel which means the carb has crud in it. Throw in the cold temps and any water in the fuel will cause it to be a problem until the carb heats up.

[jimbob200521]

I'd spend 10-15 bucks and an hours time and really narrow it down. Replace both spark plugs and the fuel line (it only takes a couple feet and you said it was already starting to deteriorate) and do what J-Mech suggested, remove the carb, drain the bowl, and give it a quick blow job to clean any crud out you can. This will eliminate fuel and spark plugs and give you a good foundation to continue testing on if the problem doesn't go away.

BTW: I also agree with John that these Mag 18's (or the design of the tractor, who knows) leads to easy water buildup in the carb and, in my experience, the fuel tank as well. If you wanted to be thorough, drain the carb AND the fuel tank and start with all fresh fuel. Also, here's a tip; don't store your gas can on a bare cement floor. It seems to hasten water buildup in the gas. Instead, sit it on a piece of wood; a couple small sections of 2x4 (this is what I do), a piece of 2x12; anything to get it off the cold cement floor

[yeeter]

Trying to get a couple videos uploaded. Not going that well, but here is one. Given its always dark when I get home (and 15 degrees out), its tough to see. I tried aiming the timing light at the carburetor - you can see the throttle pull open then a fairly slow delay until the governor catches up.

I did check the plugs and they are clean, and a little light gray. I put an inductive timing light on them and both seem to be triggering the electrical pulse.

The fuel is fresh. Letting it warm up shows no improvement.

I wouldnt mind changing out the sparkplugs. But now thinking its fuel related. Or governor?

Also it seemed to get worse when a load applied (like pushing a big pile of snow).

I will try to get the other video up and going. Not sure you can tell much from these.

http://vid708.photobucket.com/albums...astick/064.mp4

[yeeter]

Tried the second video a different way (the technology stuff isnt being too friendly to me tonight):

https://www.youtube.com/watch?v=0lBc...ature=youtu.be

Not sure you can hear it very well, and Im trying to drive with one hand while holding the phone with the other hand in the middle of a snow storm in the dark. smh

We have had approx 4 ft of snow at my house this week. Too much!

[jeepchicken5000]

since its an M18 and has a magneto, it also has a magneto kill switch wire correct ? lets say the kill wire was grounding out on the engine somewhere cause a weak spark or no spark since it is doing what its doing, have had that happen to a couple briggs vtwins and they ran like crap, id say its within that ignition module your problem is. also make sure your key switch isn't all rusty and dirty ive had them cause all kinds of problems and a new one will do wonders.

[Billy-O]

I'm leaning towards electrical. Do you have this problem in DRY conditions? With it snowing out there, snow is getting blown around motor and perhaps creating conditions just right to short out here and there.... like on older spark plug wires or bad insulation. Just a thought.