1864 Loss of power

[amanfrromthere]

I was mowing the other day and my 1864 randomly started running really rough and then died. I could barely get it to start again. Left it for a day and I was able to get it to start, but sounds like its only running on one cylinder. As soon as I try to give it any throttle, it'll just bog down. It'll move, but the engine can barely handle that regardless of throttle level.

If, when running, I pull off one of the spark plug wires, the engine will continue running with zero change. Pull the other one, engine dies immediately.

I replaced the plugs. Both appeared to be giving a spark if grounded to frame, though one side did seem to give off a stronger spark.

At this point, what's the best way to determine if it's fuel or ignition? Or is that description enough to make that determination?


Thanks

[Mike McKown]

Do you have compression in both cylinders?

[Hairtrigger]

Fuel delivery issue?

[Cubcadet_107]

I encountered a similar issue on a Simplicity Conquest with a Briggs 18hp engine. In some way, the issue was being caused by a bad air filter. It ran fine without the filter, and runs fine with the new one. However the carb also has some gunk in it still, the throttle wanders until I put it under load (engage the deck). Are you certain it didn't throw one rod? Was there a "clunk" sound when it started running rough? Easiest way to check is by turning the engine over by hand and looking into the cylinder through spark plug hole. I would say fuel issues more than anything, but I can't be certain. Your engine might have a completely different issue than mine had.

[amanfrromthere]

Originally Posted by Mike McKown

Do you have compression in both cylinders?

I don't have a compression tester

[amanfrromthere]

Originally Posted by Cubcadet_107

I encountered a similar issue on a Simplicity Conquest with a Briggs 18hp engine. In some way, the issue was being caused by a bad air filter. It ran fine without the filter, and runs fine with the new one. However the carb also has some gunk in it still, the throttle wanders until I put it under load (engage the deck). Are you certain it didn't throw one rod? Was there a "clunk" sound when it started running rough? Easiest way to check is by turning the engine over by hand and looking into the cylinder through spark plug hole. I would say fuel issues more than anything, but I can't be certain. Your engine might have a completely different issue than mine had.

In addition to new plugs, I gave a full oil change and new air filter. Also new fuel filter. No change at all unfortunately.

How loud of a clunk would it have been? But I don't think so, at least nothing that I could hear over the sound of the engine/mower (and wearing ear protection). It was sudden though, not a gradual decline.

I'll try turning it by hand and see if there's anything obvious.

I'm leaning toward fuel as well, but I'm not familiar enough with symptoms of lost compression or other internal damage to rule any of those out.

[Mike McKown]

Originally Posted by amanfrromthere

.... but I'm not familiar enough with symptoms of lost compression or other internal damage to rule any of those out.

Since you don't have a compression tester gauge, if you have a finger handy.................

Pull both plugs. Stick your finger in each hole and crank the engine. You know one cylinder has enough compression to run. How does the other one compare.

Move your spark plug wires away from your hand so you don't get a false reading.

If the problem was lack of fuel, pulling the choke out a little while it's running should smooth it out.

[Cubcadet_107]

Originally Posted by Mike McKown

If the problem was lack of fuel, pulling the choke out a little while it's running should smooth it out.

Yep, gotta agree there. Did that with my Simplicity mentioned above and the throttle stopped wandering. Try letting it run on partial choke, like Mike said. maybe it'll smooth out.

[dbuck]

I had the same problemwith my 1864. When mowing in high grass, the engine would bog down. Check the firing, was not firing on the left bank as setting in the seat. The comp was 150 both cyl's. Pulled the engine and replaced both mags. firing fine now, running better than it did before.

[dbuck]

Originally Posted by Hairtrigger

Fuel delivery issue?

Not trying to be a smart ass. But what does a fuel delivery issue have to do with not firing on one cyl?