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View Full Version : Converting 19hp Kaw 601v to a 25hp


maxrep12
04-11-2008, 03:11 PM
I purchased a new Wright Stander 19hp Kawasaki 601V. There was an out of state deal on this brand new unit that I couldn't pass up. My dilema is that I need 25hp.

From a reliable source I was told that the 19 - 21 - 23 - 25 hp models are identical with the exception of the carburation jetting. I phoned Kawasaki. Too say they were tight lipped was an understatement.

Has anyone made this jetting conversion? I was also thinking about putting on the canister filter upgrade.

Happy Frog
04-11-2008, 03:36 PM
There is a difference in the carb butterfly opening.
The easiest and most reliable way to do this is to buy a new 25 HP carb.
The hard way is to grind to butterfly stop in the carb venturi. I am not sure you actually have to change the jets. They may be the same.

maxrep12
04-11-2008, 03:46 PM
Thanks for the reply. I'm all for simplicity, so getting a 25 hp carb sounds fine. Is there a web site you might recommend for the item?

jkason
04-11-2008, 04:39 PM
When you put the canister-style air filter on you need to change out the jets also.
Just something to be aware of.

Mic_bug
04-12-2008, 10:39 AM
I purchased a new Wright Stander 19hp Kawasaki 601V. There was an out of state deal on this brand new unit that I couldn't pass up. My dilema is that I need 25hp.

From a reliable source I was told that the 19 - 21 - 23 - 25 hp models are identical with the exception of the carburation jetting. I phoned Kawasaki. Too say they were tight lipped was an understatement.

Has anyone made this jetting conversion? I was also thinking about putting on the canister filter upgrade.

buy the 25 HP carb and swap them

Jay Ray
04-12-2008, 01:02 PM
Kohler used to have identical engines with different hp, and the way they did it was a higher compression ratio for the higher hp, that is, the higher hp had the head milled a little more right from the factory. For me it is hard to believe that a change in carburetion alone can yield a 32% increase in hp, but I'm no expert, just skeptical. But if it will, that is fantastic to know.

Bill Kapaun
04-13-2008, 08:03 AM
Kohler used to have identical engines with different hp, and the way they did it was a higher compression ratio for the higher hp, that is, the higher hp had the head milled a little more right from the factory. For me it is hard to believe that a change in carburetion alone can yield a 32% increase in hp, but I'm no expert, just skeptical. But if it will, that is fantastic to know.

I'm even more skeptical about the same engine having more torque by putting on a bigger carb.

LarryF
04-13-2008, 08:35 AM
Kohler used to have identical engines with different hp, and the way they did it was a higher compression ratio for the higher hp, that is, the higher hp had the head milled a little more right from the factory. For me it is hard to believe that a change in carburetion alone can yield a 32% increase in hp, but I'm no expert, just skeptical. But if it will, that is fantastic to know.

That's my opinion too. "If it sounds too good to be true.............etc." And if you do change the carburetor, I have to wonder if you will test or even be capable of testing the result to confirm that you really do get up to 25HP. I have an idea you'll be wasting both your time and money if you try this.

rjxj
04-13-2008, 11:00 AM
It seems very unlikely that you can get that much hp with a carb change. I will check it out at work on Monday. I know there are at least three different head gaskets available with different diameters, so there must be different bores.

Happy Frog
04-13-2008, 03:06 PM
This issue as been discussed at length on this forum. Just do a search and you'll find a few treads about this.
The only difference in parts numbers on the Kaws 19-25 HP is the carburetor.
If you are unsure, check the parts numbers yourself is the parts catalog for these engines.

LarryF
04-13-2008, 03:58 PM
Thanks for the suggestion, but I did a search before submitting my previous post looking for someone who had actually done it and also claimed to have proven success by virtue of measuring the HP after the conversion. Others may have talked about it and someone may have actually changed a carburetor, but whether or not it made a difference would be the important point. I wasn't successful finding such a post, and that's why I don't think it's really possible to increase the HP from 19 to 25 (a 31.6 percent jump as Jay Ray pointed out) simply by changing the carburetor. But if that post does exit, perhaps you'll be good enough to direct us to it.

TLS
04-13-2008, 04:08 PM
Well, they're all 675cc's

By having the baby engine of the group (19hp) at least you have the same SIZE engine as a 25hp!

I believe I heard it was more than just the carb. Either ignition timing or cam shaft....cant remember.

Bill Kapaun
04-13-2008, 05:18 PM
This issue as been discussed at length on this forum. Just do a search and you'll find a few treads about this.
The only difference in parts numbers on the Kaws 19-25 HP is the carburetor.
If you are unsure, check the parts numbers yourself is the parts catalog for these engines.

Some time back I "investigated" the difference between the 18 & 20 HP Vanguards.
I downloaded the IPL's for each and basically came down to the same conclusion! The 20 HP had a different carb & intake (2 barrel vs 1 barrel carb) and different decals. Piston, crank, cam, head, block etc. were the SAME part#'s.
Interestingly, the 18 HP had slightly better torque numbers (max). I attributed that to better fuel mixing with the smaller carb at lower RPM.s where the air flow through the carb is reduced.
Torque/HP charts-
http://www.tewinc.com/pdf/350700.pdf
http://www.tewinc.com/pdf/351700.pdf

My basic conclusion was the the 20 HP WAS more "powerful, as long as the speed remained near 3600 RPM. Once the engine started to noticeably "bog", the 18 HP would "chug" better.
IF the engine doesn't bog, who cares what the HP rating is?
To the OP-
Have you actually used the engine on the job? Maybe the lower rated engine is really a wolf in sheeps clothing?

TLS
04-13-2008, 11:20 PM
Maybe the lower rated engine is really a wolf in sheeps clothing?

Thats what I was getting at. 675cc's is big for a 19hp engine, while 675cc engines don't really belong in the 25hp scene.

rjxj
04-14-2008, 09:41 PM
This issue as been discussed at length on this forum. Just do a search and you'll find a few treads about this.
The only difference in parts numbers on the Kaws 19-25 HP is the carburetor.
If you are unsure, check the parts numbers yourself is the parts catalog for these engines.

compared part numbers on three of them today and they are the same. Same pistons, heads, valves, cam. There are different part numbers for all the carbs. The thing that caught my eye was the $350.00 price tag for the two barrel carb.

Jay Ray
04-16-2008, 09:51 AM
Is crank the same, same stroke?

TLS
04-16-2008, 10:09 AM
Yes, same cc's, same stroke.

LarryF
04-16-2008, 10:15 AM
compared part numbers on three of them today and they are the same. Same pistons, heads, valves, cam. There are different part numbers for all the carbs. The thing that caught my eye was the $350.00 price tag for the two barrel carb.

What were the respective carburetor prices for the 19, 21, 23 and 25 HP engines?

rjxj
04-16-2008, 07:27 PM
What were the respective carburetor prices for the 19, 21, 23 and 25 HP engines?

I will try to check it out tomorrow

shopman
04-20-2008, 01:15 PM
Its just the throttle shaft check the part numbers.

LarryF
04-20-2008, 01:31 PM
I will try to check it out tomorrow

rjxj, were you able to find the carburetor prices for each of the four engines?

Tharrell
04-24-2008, 12:21 AM
Gee, I want to know if I really have a 25hp on my wb? Tony

rjxj
04-25-2008, 10:29 AM
fh721 # 1500-7042, fh680 #15003-7120, fh641 #15003-7078, all three are about $346.00 Those are kaw numbers, there are probably numbers stamped in the carb body also. I know we have one used carb, but not sure of the HP.

LarryF
04-25-2008, 11:33 AM
fh721 # 1500-7042, fh680 #15003-7120, fh641 #15003-7078, all three are about $346.00 Those are kaw numbers, there are probably numbers stamped in the carb body also. I know we have one used carb, but not sure of the HP.

Thanks rjxj! Well, I guess the several hundred dollar difference between a 19 and 25HP Kawasaki engine isn't because of the cost of the carburetor. You provided only the cost of carburetors for the 25, 23, and 21HP engines, but I presume it's about the same for the 19HP as well.

Lawn-Sharks
04-25-2008, 12:55 PM
I have seen the spec sheets on the kawi engines and yes the 19 to 25 have the same specs just different carbs but my thought is why would you spend the extra money for a carb just to pick up a few hp. sure it sounds good but what you really need is torque. and just because something can breath a little more and pick up some hp doesnt mean its going to pick up as much torque as it did hp so is it cost effective? to do this mod. or is it the Tim Allen impulse???? good luck with it all and let us know how it works out 4U

Happy Frog
04-25-2008, 01:20 PM
These engines are all 25 HP engines.
They are just derated through the carb to fit different needs.
Changing the carb will increase the power and the torque.
To make it simple, you can look at power and torque like this:
More power will allow more work to be done in the same amount of time (taller and thicker grass can be mowed at same speed).
More torque will allow the engine to sustain its rpm when under heavier load, keeping it in the max. power range.

LarryF
04-25-2008, 04:32 PM
I have seen the spec sheets on the kawi engines and yes the 19 to 25 have the same specs just different carbs but my thought is why would you spend the extra money for a carb just to pick up a few hp. sure it sounds good but what you really need is torque. and just because something can breath a little more and pick up some hp doesnt mean its going to pick up as much torque as it did hp so is it cost effective? to do this mod. or is it the Tim Allen impulse???? good luck with it all and let us know how it works out 4U

The problem with that argument is that according to what rjxj reported, all the carburetors are about the same price, so there must be something else besides the cost of the carburetor that justifies the extra several hundred dollars for a 25HP over the 19HP. There is speculation in this thread that it's the carburetors, but not everyone is convinced of that, not yet at least. Also, Lawn-Sharks' statement that more HP doesn't mean more torque is not necessarily true. The following data, which came from those specs he referred to, demonstrates that point.

Torque Dry Weight
FH580V; 19HP; 36.6 ft lbs @ 2000 rpm; 71.2 lbs
FH641V; 21HP; 38.4 ft lbs @ 2400 rpm; 88.2 lbs
FH680V; 23HP; 39.8 ft lbs @ 2400 rpm; 88.2 lbs
FH721V; 25HP; 41.3 ft lbs @ 2400 rpm; 90.2 lbs

In addition, although the bore & stroke and therefore the displacement are admittedly the same for all four engines, the dry weights are not, and the above data shows that the 25HP is in fact 19 lbs heavier than the 19HP. It's pretty hard for me to believe that difference in weight could be attributed to different carburetors. So, to me, that's further evidence that no one will be able to convert a 19HP Kawasaki into a 25HP simply by replacing the carburetor.

GravelyNut
04-25-2008, 05:08 PM
Changing carbs can make a difference in HP output. In car racing, engine sizes can be the same, or different. But putting a restrictor plate in will make all of the engines think they are the same. SCCA did this, as an example.

Same thing was done by the car makers. Different HP output with a 2 barrel carb vs a 4 barrel carb. Rest of the engine could be the same.

In Kohler's past, they made both 16 and 18 HP Magnum engines for Gravely which used the M18S tag. The governor setting and the carb jets made the 2 HP difference. Same sort of thing is done by B&S as you can get engines that are the same block with different ratings.

In computers, it's called "underclocking". While the chip may work at one speed from the factory ( 677 MHz for example ), it could be really a faster chip ( 1000 MHz ).

olde_blue
04-25-2008, 08:55 PM
[QUOTE=LarryF;2290287]
Torque Dry Weight
FH580V; 19HP; 36.6 ft lbs @ 2000 rpm; 71.2 lbs
FH641V; 21HP; 38.4 ft lbs @ 2400 rpm; 88.2 lbs
FH680V; 23HP; 39.8 ft lbs @ 2400 rpm; 88.2 lbs
FH721V; 25HP; 41.3 ft lbs @ 2400 rpm; 90.2 lbs

QUOTE]

The FH580V is a smaller displacement 19 hp engine (585 cc--shares displacement with the 17 hp FH541) than the 19 hp FH601V (675 cc). It should produce arround 37.0 ft lbs @ 2400 rpm.

LarryF
04-25-2008, 09:21 PM
[QUOTE=LarryF;2290287]
Torque Dry Weight
FH580V; 19HP; 36.6 ft lbs @ 2000 rpm; 71.2 lbs
FH641V; 21HP; 38.4 ft lbs @ 2400 rpm; 88.2 lbs
FH680V; 23HP; 39.8 ft lbs @ 2400 rpm; 88.2 lbs
FH721V; 25HP; 41.3 ft lbs @ 2400 rpm; 90.2 lbs

QUOTE]

The FH580V is a smaller displacement 19 hp engine (585 cc--shares displacement with the 17 hp FH541) than the 19 hp FH601V (675 cc). It should produce arround 37.0 ft lbs @ 2400 rpm.

Thanks olde_blue, I stand corrected. But I didn't see the FH601V on the web site I had looked at.

http://www.kawpowr.com/4cycle/vertical.asp

If your data came from a different site, may I have the URL?

But nonetheless, my contention that more HP coincides with more torque remains.

Shultz38
05-14-2008, 03:45 AM
OK, I must respond to this so nobody buys carbs that won't fit or wastes any time on this like I have. The part numbers that you all must be referring to are Reference numbers only and are not the true part numbers. The reference numbers only describe the part but does not reflect the true part number. The engines are different and have tons of different parts, not just the carb. Please look further into this before posting such claims. My hopes were high only to be dashed after wasting time to debunk this myth. Look at the manifold; completely different, and it doesn't stop there. GEEEZ. The true question should be, "Can I put a bigger engine on my Wright 52 RH stander?" Please let me know. I'm not sure if there is enough room or not. It's not completely under powered, but I gotta be over powered to be happy. I also have a Wright32 17 hp and love it. And just 2 more HP on my 52 WTF? Let me know what I can do. I already bought the baffle.

LarryF
05-14-2008, 08:15 AM
OK, I must respond to this so nobody buys carbs that won't fit or wastes any time on this like I have. The part numbers that you all must be referring to are Reference numbers only and are not the true part numbers. The reference numbers only describe the part but does not reflect the true part number. The engines are different and have tons of different parts, not just the carb. Please look further into this before posting such claims. My hopes were high only to be dashed after wasting time to debunk this myth. Look at the manifold; completely different, and it doesn't stop there. GEEEZ.

Good post, Shultz38, and a much needed one. :clapping::clapping:

I hope it puts this silly idea to rest permanently.

Happy Frog
05-14-2008, 04:24 PM
Thanks for finding and sharing this.