FR691V Kawasaki Engine Vs. FX691V Kawasaki engine

[Zeroturner]

With the kind help/research of nwatson99, I see the difference between a FR691V Kawasaki engine and an FX691V being the FX comes with the addition of:

Dual stage canister air filter
Cast-iron cylinder liners
Metal engine cover
Heavy-duty shift-type starter
Twin barrel, internally vented carburetor with fuel shut-off solenoid

Due to my ignorance, I don't know which of these particulars is the most beneficial. I realize the FX often come with commercial machines.

Why do I want to be schooled on the differerences?

I may have to buy a new ZT mower, so I'd like to know as much about these engines as possible and how much more I can get out of an FX vs. an FR. I also don't if the FR is basically an FX without the five above extras, if you will...

I can certainly see the benefit of having a better air filtration, but how do Cast
-Iron cylinder liners benefit you?

Longevity of engine life?

I don't see the benefit of a metal engine cover, unless one is a traditionalist. It would seem (hey, remember, I'm just speculating..) a plastic cover is a plus in the weight department, so why would a metal engine cover be better?

Anyway, if some of you super knowledgable guys could provide a detailed breakdown of why the above extras that come with an FX engine is way better than what comes with an FR, I'd be most grateful and much more informed.

Thanks!

 

[motoman]

Zero, I will comment on the cast iron cyl liners from a general view. They are stable and rigid. When honed properly they facilitate break- in of rings. The cast iron grain holds oil film very well, which promotes long cyl life. Cast iron accepts vibration well.

Aside..I am interested in Kaw because I may buy the garden tractor version.

 

[Zeroturner]

Motoman,

Due to my extreme ignorance, this sentence may as well have been worded in Swahili (which I actually know at least two words of) for me: "When honed properly they facilitate break- in of rings.

Does that mean if the factory did their job right or ...?

Or, am I responsible for the honing or is it a roll of the dice, or ...?

And thanks, I'm one of those guys who are willing to learn late in life, have an interest in this stuff, without anyone earlier in life who taught me a damn thing about engines or things mechanical in general.

I am a total neophyte.

I'm not, however a beginner to hard work.

That I have a Phd in....

 

[motoman]

Zero, Fear not , and glad you are learning. The cast iron cylinders are honed at the factory. Proper ring break in results in better sealing of combustion gases , more power ,less blowby into the oil pan. During splash of oil a film is held by the tiny (natural) pores in the cast iron which provides a good surface for the piston and rings to run over. It probably costs Kaw more to install the cast iron liners in (?aluminun block) the engine than just boring (aluminum? or cast iron). I am not familiar with the engine, so some guessing here. GM tried to be like Porsche back in the days of the Vega, and run directly on an aluminum surface. Not good. The fix was iron liners.

 

[Zeroturner]

motoman,

Thanks for the help.

I'm still wondering about the other four items, if anyone else can chime in on them, I'd be most appreciative.

Thanks again motoman!

 

[motoman]

Zero, Well since no one else is talking I will wing it on the cover. I don't even know where the cover goes, but plastic is still prone to heat warping , drying and cracking while mild steel, for instance is not. If you search here you will hear people complaining about warped plastic intake manifolds. I like plastic , but it does have some problems.

And now for my most unsure answer, the two throat carbs. If an engine has two cylinders theoretically two throat carburetors are more efficient, allowing the tuner to adjust mixture strength slightly differently for each cylinder. In high performance engines intake tracts are tuned for torque/horespower and the carb throats are part of it. But that cannot apply to a low rpm tractor motor so I do not know what advantage there is except gas consumtion, perhaps. Internal venting is greek to me, perhaps a safety feature if the carb is flooding. Here we need the pros who know these air cooled engines well enough to tell you what advantages there may be. Maybe, my blathering wil give them incentive. I do know solenoid fuel cut offs are very common and so including that in an ad seems like fluff.

 

[Nwatson99]

I am not a engine mechanic, but here is my opinion on the items you have listed:
Dual stage canister air filter: Better filtration and air flow
Cast-iron cylinder liners: These are best for the operation of the piston and heat dissipation, also cast is well known for holding oil in the pores of the material vs. other material will not.
Metal engine cover: A bonus for overheating and not warping, plus it is stronger and will not "dry rot" or break down from the heat.
Heavy-duty shift-type starter: Heavy duty starter is always better and handles the heat better.
Twin barrel, internally vented carburetor with fuel shut-off solenoid: The shut off solenoid is pretty much a sale for me, this is a awesome feature in the FX and I had to ask why the extra fuel line was for the FX engine which was to put un-used fuel back into the system from the carb.

Hopes this helps man and if I was you I would do the better engine and roll from there.

 

[Mad Mackie]

Go to kawpower.com and read what Kawasaki has to say about their different engine lines.

 

[motoman]

Mackie, Thanks for the lead. I looked at the owners manual on the 750FX , and three things stood out to me. A good looking , large aircleaner. The "oversquare" pistons must be a spillover from Kaw's motocycle design (piston dia larger than stroke). A bit surprising when torque is the object. Last an OIL COOLER!. I could not see any fan so perhaps some blast is provided from the fan. If B&S would put on oil coolers I bet their field failures would drop 30%. Maybe they need the turnover, but bad PR. motoman

 

[Zeroturner]

Thanks to each and everyone that's contributed to this thread.

Until recently, I didn't know there are so many different Kawasaki engine models powering ZT mowers on the market.

I naively thought that if a Kawasaki engine is powering your mower, hoo whee, you were good to go. Yeah buddy, First class engine all the way! Not realizing there are many different quality levels within Kawasaki engines.

Now I wonder if an FR is light years lower in quality than an FX and is maybe on par with a B&S Intex, but the Kawasaki name goes a long way in marketing to the public...?

Or, no, even an entry level/basic quality Kawasaki engine is still way higher in overall quality than say a B&S Intex (or equal)?