Don't run the machine on one cylinder!!! The unburned fuel that is entering your cylinder is washing your cylinder walls and some of the fuel will find its way in your sump diluting your oil. Your hydro system is also not getting all the power it needs to run right!

 

no kidding dont run that engine fuel washes the oil right off the wall and it is wearing out sooooooo fast if you dont quit it will be blowing smoke when you fix it!!!

 

Please tell us this is a joke.

Please.

 

Do people not use common sense?

 

I had a coil go bad today on a 17 horse Kawasaki attached to a Scag hydro walkbehind. The 15 to 25 pre kai Kawasaki's coils have been a problem for me, I'm lucky if I get a 100 to 200 hours before a coil goes bad. I keep spare Kawasaki coils in stock at all times.
I agree with what's been posted by other's here, do not run the engine on one cylinder, it's not very good procedure to put the engine through, you come up with a seized engine.

 

The two new coils have arrived today. The mower only ran for 12 hrs on one cylinder. I am changing the oil as well in case it got thinned out from fuel leaking by the rings. If I could ever get parts when I needed them I would have fixed it the same day. But as always I had to order them.

I guess I didn't realize the potential damage that may occur. But at the same time I had $1k of lawns that had to be cut and none of the dealers around had any coils in stock.

 

A good dealer should have given you a demo model to use while your parts were being ordered.

 

A good dealer should have given you a demo model to use while your parts were being ordered.

Even if you are only buying the parts and not having them do the installation?

 

Even if you are only buying the parts and not having them do the installation?

What part of N.H. are ya from???? Dealer out our way does.

 

Lock the motor up and it will cost you more then the $1K you made. This has to be the dumbest thing I have heard in a long time. 12 hours on one cylinder is alot. Better start saving up for a new motor as you probably cut the life span of that down quite a bit.

 

Yes, running the engine on 1 cylinder puts a lot of stress on it. The engine is designed for both cylinders to work in tandem. Do not do this unless it is an emergency to get it back to the truck or some thing. THINK!!!

 

Lock the motor up and it will cost you more then the $1K you made. This has to be the dumbest thing I have heard in a long time. 12 hours on one cylinder is alot. Better start saving up for a new motor as you probably cut the life span of that down quite a bit.

I completely agree.

Better keep an eye on the cylinder that was out. You've damaged it, to what extent I don't know...

Why the hell wouldn't you just get a demo for the day, even if you had to pay to rent it?

 

Even if you are only buying the parts and not having them do the installation?

Absoultly, how do you think they sell you a new machine? They want you to try the newest stuff with all the improvements.

 

Man, everyone is so nice on this site. I have over 1400 hrs on this engine. If it something happens to it I will take it as a lesson learned. So far it is purring like a kitten and hasn't used a drop of oil.

I have also never balance a blade in my life and to this day have never replaced a spindle!

Now mechanically speaking I have better understanding than most of vibration and engine design being that I am a mechanical engineer as well. Looking at things more closely I would think that the chamber must be big enough that the unburt fuel from no spark will not be compressed anymore than the air to get by the rings and contaminate the oil. I agree that the engine will be working but I am unclear the physics of what is getting damaged. The rings, cylinder wall, what exactly is getting damaged??

Since this is the dumbest thing you have ever heard you must have a clear explaination of exactly what and why things are getting damaged. Please advise.

 

The unburned fuel that is entering your cylinder is washing your cylinder walls and some of the fuel will find its way in your sump diluting your oil.

This is COMMON SENSE.

Not sure where you got your degree from but I think you should get a refund.

 

The unburned fuel that is entering your cylinder is washing your cylinder walls and some of the fuel will find its way in your sump diluting your oil.

This is COMMON SENSE.

Not sure where you got your degree from but I think you should get a refund.

Exactly correct standard ring tension and compression only partialy seal the ring the rest is accomplished through combustion.

The combustion pressure spreads across the upper ring surface and down behind the ring, and forces the ring out against the cylinder wall. The radial pressure of the ring tension is only used to START the sealing process, and cylinder pressure is what really pushes the ring outwards against the cylinder wall. For this to occur, the ring gap and piston to ring contact surface must be perfect.

Glad your are cutting grass and not a mechanical engineer.

 

Exactly correct standard ring tension and compression only partialy seal the ring the rest is accomplished through combustion.

The combustion pressure spreads across the upper ring surface and down behind the ring, and forces the ring out against the cylinder wall. The radial pressure of the ring tension is only used to START the sealing process, and cylinder pressure is what really pushes the ring outwards against the cylinder wall. For this to occur, the ring gap and piston to ring contact surface must be perfect.

Glad your are cutting grass and not a mechanical engineer.

Completely true. Also the amount of fuel in the fuel air mixture is very small. If the carburetor is working correctly the mixture will be atomized enough that it will go right on out the exhaust port with the air.

 

And if the pistons aren't gas ported(which I would doubt they are on these engines), you get even less of a seal to the cylinder walls with the rings. Of course that doesn't matter when there's no combustion happening in the chamber anyways...

 

Nope I pay someone to drive the mowers all day for additional income. I am a full time engineer. I have seen guys on this site that have gotten less slack for not knowing how to convert cubic yards to cubic feet.

I changed the oil right after I replaced the coils and it did not apear any thinner than usual, although it may be hard to tell. But it sounds like the damage that could ocurr is due to the thinning of the oil which would reduce the lubrication qualities slightly. I could see where this could cause damage over long periods of time but do not see how 12 hours of operation would severly dilute the quality of the oil.

I won't argue wheather it is COMMON SENSE or not about gas slipping past the rings into the oil. What I am argueing is if a few hours of operation on 1 cylinder destroys an engine.

It may also make you feel better that I am not an engine designer. Instead I get to design radars for military applications which luckily for me are usually drive by nucular or diesel powered generators.

 

I would worry just as much if not more about hydro pump damage. These hydro systems are designed to run with the engine at full throttle (3600rpms) to keep the rotating groups seated and port the oil where it needs to be. Running on one cylinder, the pumps are NOT getting the full power that they need. If the rotating group is not running at full power the slippers can wobble and prematurely wear rather fast. Engineer or no engineer.....some of us have been working on these engines and hydro systems for 20+ years and have seen the damage that can be done by running on 1 cylinder. I won't say someone is "stupid" for doing it but maybe a little misinformed.

 

I would worry just as much if not more about hydro pump damage. These hydro systems are designed to run with the engine at full throttle (3600rpms) to keep the rotating groups seated and port the oil where it needs to be. Running on one cylinder, the pumps are NOT getting the full power that they need. If the rotating group is not running at full power the slippers can wobble and prematurely wear rather fast. Engineer or no engineer.....some of us have been working on these engines and hydro systems for 20+ years and have seen the damage that can be done by running on 1 cylinder. I won't say someone is "stupid" for doing it but maybe a little misinformed.

That is a respectable answer. I would whole heartedly agree that I was not as aware as I should have been about the potential damage.