[Nonbiased Guy]

Ok so I got my Z930m 54” MOD with fully adjustable suspension seat for my compact/residential ztr. Now when looking at 60 plus size decks it seems scag is the best. I know I dont want a Kohler, I want power to push through the toughest conditions so the possible engines Im looking at are

31 HP Kawi
35 HP Briggs Vanguard
37 HP Briggs Vanguard EFI
25 HP Kubota Diesel

Which engine will be the hardest to bog down? My guess is the Kubota or the larger Vanguard

Which engine will be easiest to maintain? My guess 35 Hp Vanguard

Which Engine will be the most fuel efficient?
Obviously the Kubota, my guess for second EFI Vanguard.

Anyone’s experiences with any of these 4 engines will be appreciated, thanks

 

[TPendagast]

Scags biggest mistake was leaving Briggs vanguard
It used to be on all their engines
Then they started this kawisucky thing and the company has lost sales and even given birth to other competitors as a result they will never recover from.
Used to be you could get a Briggs on every scag
Not so for a long time now

Briggs has always been the best choice

 

[Nonbiased Guy]

View attachment 359547

 

[Nonbiased Guy]

The Kawasaki FD series seems over exaggerated on horse power. When you look at the FX series on the z-trak john deere. The fx801v is rated at only 25.5 hp and has just under 45 ft lbs torque. The FD851d is rated at 31 hp and only has 47 ft lbs torque. When you check out the fx921v on the deere it has 31 HP only 54 ft lbs torque...thats alot more torque than the engine rated on the scag. So it would seem the above answer by TPendagast is correct. The Vanguard is the best offered engine. Surely some Kawasaki fans have an answer too though.

 

[Traveling Man]

I too struggled with this issue and my choice was the Vanguard 35HP motor. My dealer suggested I steer clear from the Vanguard EFI model and I trust his opinion.

 

[Nonbiased Guy]

I cant find the torque specs for the diesel anywhere. Im guessing its around 50 ft lbs. The FD851d is weak compared to the Vanguards stats. I wish they offered a simple FX921v 54ft lbs torque or a FX1000v 56 ft lbs torque Kawi. The liquid cooling seems unnecessary considering how long air cooled will last with good Amsoil. Heck my little z930m 54 mod deere has almost as much torque as the FD851d.

 

[Nonbiased Guy]

I too struggled with this issue and my choice was the Vanguard 35HP motor. My dealer suggested I steer clear from the Vanguard EFI model and I trust his opinion.

I hear ya on the EFI. Kohler probably has that mastered but they overrate their power on their engines. Ive dealt with an under powered engine before and that was a bigger hit in profit then fuel efficiency.

 

[weeze]

37 efi is the same engine as the 35 non efi i would imagine. the only difference is the efi. vanguard uses the same efi system as kohler made by delphi so it's good to go. 37hp efi is the best way to go.

 

[Jmcculler]

I have the 37hp efi vanguard with the oil guard system on my ferris 61" no complaints at all. Cut down some 3ft tall pasture last week with it. Ran over it once with the deck up and once lowered.

was actually the backside of this lake. this pic was taken last year.

Might ask yourself why so nice on one side of the lake and messy on another. . Love this customer, she says she wants a perfect habitat for all the snakes on the opposite side of the lake her house is on so they stay the hell over there. We clean it up once a year.

 

[Valk]

Seems to me that torque ratings at full throttle matter more than peak torque which is lower in the power band. In the KAW examples above, the FD is making 20%+ more torque than the FX at 3600 RPM. (46-ish vs 37-ish)
.02

 

[weeze]

Seems to me that torque ratings at full throttle matter more than peak torque which is lower in the power band. In the KAW examples above, the FD is making 20%+ more torque than the FX at 3600 RPM. (46-ish vs 37-ish)
.02

the torque comes into play once the engine starts to bog down from thick/wet grass so the rpms will be a tad lower than 3600. most every engine runs lower than 3600 from the factory anyways. most are set to about 3400 from the start. my kohler efi was at 3450 and i moved gov spring to raise the rpms and it went up to 3550 but it's still not at 3600 but it's close.

i checked my old kawi engine before it blew up and it was running at about 3200rpms max.

 

[weeze]

my deere z920a 54" deck came with the 23.5hp fx730v engine. it was no where near enough power. i now have a 27hp fx850v engine on it and the power is awesome.

http://www.kawasakienginesusa.com/engines/fx/fx850v

they don't even sell that size deck with that engine. it's only offered on 60" decks. to me this is how they should be set up from the factory. for some reason most every mower is under powered these days. maybe it's for emissions reasons or something i dunno. they should at least put the 25.5hp fx801v engine on all of their 54" decks. anything less than that is not enough power. the fx730v may be ok on a 48" deck or smaller.

 

[Nonbiased Guy]

my deere z920a 54" deck came with the 23.5hp fx730v engine. it was no where near enough power. i now have a 27hp fx850v engine on it and the power is awesome.

http://www.kawasakienginesusa.com/engines/fx/fx850v

they don't even sell that size deck with that engine. it's only offered on 60" decks. to me this is how they should be set up from the factory. for some reason most every mower is under powered these days. maybe it's for emissions reasons or something i dunno. they should at least put the 25.5hp fx801v engine on all of their 54" decks. anything less than that is not enough power. the fx730v may be ok on a 48" deck or smaller.

I totally agree, I ordered the largest engine I could with the smallest MOD deck. The Z930m "fx801v" lets you order a 54" or 60" MOD deck, So I ordered it with a 54" MOD

If I were to get a 60" it would have been the z960m with a fx921v but I needed a mower that will fit in a cemetery setting. I looked at a Z920m with a 48" mod, but the idea of slopes made me realize i needed a wider setup.

 

[Nonbiased Guy]

Ok guys, math to solve the answer, I was given a power curve for the vanguard 37 EFI and 35 carb engines. Mathematics solves the torque

HP*5252/rpm

So the 31 HP Kawi offered (FD851d) holds a nice torque band around 45-47.5 ft lbs at higher 3000 RPM range.

The Kohler reaches 40 ft lb at a moderately high rpm and ends at 38 ft lb at 3600 RPM

The Kubota you get a pretty constant 41-42 ft lb torque band.

The Briggs 37 EFI dominates the torque curve by constantly passing 50 ft lbs most of the power curve and sits around 54 ft lbs most the upper 2600 plus RPM dropping to 53.98 ft lb at 3600 RPM

The Briggs 35 sits in between the 31 Kawi and 37 EFI briggs, howerver the curve isnt quite as good as the 37’s constant levels.

So verdict in,

Any one of these engines will last the life of the rest of the mower if maintained properly so it comes down to gph and mowing productivity.

The Kohler and Kubota will edge out on the best GPH, however neither will run a 61” deck as well as the larger engines.

Obviously Kohler on 52” only choice unless custom ordered.

61” Kubota should do if side discharge is only used and you mow in ideal conditions mostly (we dont always get that choice, plus the price of this combo is extremely high)

The FD851d Kawi would be the best choice for fuel efficiency and power combination with the 61 in most conditions.

Both Vanguards will be overkills with the 61” but no worries, if you dont mind a little extra fuel. (Still cheaper than kawi version and would take alot of fuel hours to catch the difference at 2.50 gal gas)

Moving up to the 72”

Kohler is fail, and Kubota would struggle. Kawi makes it in ideal conditions

Looks like the Vanguard 37 EFI dominates this deck with Constant mid 50 ft lb torque curve. Barely cost more than the 35hp Vanguard and more fuel efficiency and power.

All merely a guess from common sense however real experience wins every time if I’m wrong.

 

[weeze]

there's no such thing as too much power. you can bog down any engine mowing thick stuff. it's just do you want to mow thick stuff at 6mph or at 2mph? that is where the difference comes in really. time.

a carb big engine will drink the fuel but an efi big engine doesn't do so bad on fuel. you are getting 6 more hp on the 37hp efi and using less fuel than the 31hp kawi engine so it would be a win, win situation.

 

[BSIA]

Go with the Briggs 37 EFI Most power and really fuel efficient I just bought One guy said he got 1.4 gallons per hour on his fuel test This is the best mower I have ever owned I traded 2017 TT2 with 27efi Kohler That engine couldn't pull a grease string out of a cats behind

 

[Nonbiased Guy]

Anyone have an opinion on how the 72” scag maneuverability is compared to the 61”. Slopes etc?

 

[CGros31]

Don't count out the Kubota diesel. They have great torque, will last much longer than the machine ever will, and it will by far be more economical with fuel. The service intervals are longer as well.

 

[Nonbiased Guy]

Don't count out the Kubota diesel. They have great torque, will last much longer than the machine ever will, and it will by far be more economical with fuel. The service intervals are longer as well.

Im sure your right, but its like 5000 more i think for it

 

[CGros31]

Im sure your right, but its like 5000 more i think for it

No doubt it will be higher. I have a diesel ZTR myself, and you get what you pay for.