1864 Loss of power
 

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

Do you have compression in both cylinders?

Fuel delivery issue?

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.

I don't have a compression tester

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.

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.:biggrin2:

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.

1864
 

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. :American Flag 1:

Not trying to be a smart ass. But what does a fuel delivery issue have to do with not firing on one cyl? :American Flag 1:

Some auto parts stores will let you borrow a compression tester.

If he is low on fuel no one says that it is actually firing on that cylinder
The original post said he had spark at both plugs but one appeared to be stronger spark

Read post #1. He said it will run on one cylinder but not the other. Classic loss of compression in one hole.:beatdeadhorse:

I suggest you pull the valve cover and check for a push rod that got out from under the rocker arm.

The good side blew my finger out right away, other side did basically nothing.

See post #14.

https://www.onlycubcadets.net/forum/...ad.php?t=57354

Yup, that'll do it. I'll check on the things you mention in that thread.

https://lh3.googleusercontent.com/59...-no?authuser=0

Welp, guess that's why it came off. Barely any force on it and it just failed.

https://lh3.googleusercontent.com/V-...-no?authuser=0

Looks like you can't just buy the rocker arm, gotta buy this the whole valvetrain replacement set: includes (4) push rods; (4) rocker arm pivot; (4) stamped rocker-cyl saddle arm; (4) hex flange screw
https://www.partstree.com/parts/cub-cadet-kh-24-755-66/

Knowing the rocker arm broke, is there anything else I should look for or replace?

I would check for a stuck valve.

I'd bet money it's a head gasket. I have two Cubs down right now with that issue. It is the Achilles heel of that engine.

Compression testers are cheap. Buy or borrow one.