View Full Version : Monster Horsepower !!! ;-)

03-06-2004, 08:46 PM
Hi All

I have a 48" Exmark TT HP walkbehind .....
Engine smokes a little and was thinking of replacing it before too long....I received my latest supply catalog and researched potential replacement engines.....My current engine is a Kaw 420 V ......I was looking at the factory specs for this engine and to my surprise a new 25 HP electric start twin cylinder engine has the exact same shaft diameter and length....I would not be adverse to drilling new bolt holes if needed and making other mods as needed to make it work (adding a battery tray for instance and cutting a hole for the key start.....Anybody have any opinions on this ?.....Has anybody out there done it?
I'd imagine a 25HP engine on a 48" cut would make for great no bog mowing performance .....(I prefer to stay at 48" max so I can run the mower into the back of my Dodge Pickup .....a 52" TT
won't fit and since all my other mowers are the same the parts interchangeability is great......Also, I was thinking of using an electric clutch setup if I do this switch to eliminate 1 additional belt in the drive system (If you're familiar w/ the machine it's the
small belt that tightens up when the blade drive lever is pushed to sctivate the blades.....Any ideas if the electric clutch is worthwhile or just keep the same mechanical engagement?........I fo alot of 2 week mows so I'd think the extra power and maybe running doubles would make for some quick
1 pass mows ( Yes, I do have a zero Turn ....But some places it just can't be used).....

Thanks in advance for your input, ideas, and advice.....(Oh BTY the new engine is $1700 not incl shipping)....rest of mower is in excellent mechanical shape)....


Fareway Lawncare
03-06-2004, 08:56 PM
Hello, I have a 36"/17hp Kaw TTHP . eXmark did not recommend going larger than a 19hp on a HP frame. After some experimenting I have concluded that anything over a 19hp on the 48" Tri-Vantage & 17hp on the 36" Tri-Vntage decks is overkill as the deck can only process so much clipping volume regardless of engine size.

Please do not replace the manual clutch w/electric. The manual has a very easy belt adjust system on the TTHP's & is much less expensive to maintain.

03-06-2004, 09:21 PM
Thanks for the reply.....I cut alot of 2 week
yards and the 14 hp bogs alot....was thinking the extra HP would help alot in that situation.....Having a welder, I suppose I could weld on some reinforcemets to beef up the Frame....the
deck looks strong but I suppose I could
weld on some angle iron as well.....

Thanks for your idea on the clutch....I guess that's one less mod to make !
(was just thinking getting rid of another
potential area of slippage would be good)......

Thanks !

03-07-2004, 10:11 PM
hey Andy if you have too much work on that side of the mountian give me a hollar i have been looking to pick up some work over there commercial only

03-08-2004, 08:25 AM

You might want to try one of these!:D

48", deeper deck, 23hp, larger tires, h-bar steering.:D

03-08-2004, 12:51 PM
Andrew you might opt for the 23 Hp. You may be able to save a few bucks.
I read somewhere that the 23 and 25 hp Kawasakiís were the same engine, they just did something different to the carburetor. (Maybe someone with more knowledge will elaborate on this?) I have a 25 Hp SWB and have bogged it down before mulching leaves.
I agree with FarewayLawncare, I would keep the manual clutch instead of going with the electric. They are simple and a lot cheaper! If the frame isnít strong enough for the weight or power of the engine you can always replace it with stronger material when it shows signs of fatigue. Good luck!


03-08-2004, 01:51 PM
I'm replacing a 17 hp Kawasaki on my Ferris with a 23 hp electric start right now. There are a few other things you'll need to make the conversion to electric start that add up, beyond the $1700 for the engine. You need a new wiring harness ($106!), the switch, a starter solinoid, battery cables, a battery, etc. All together this stuff added up to about $260 over the cost of the engine.
I would probably do it, it just gets expensive because the high hp engines are only available in electric start.

03-08-2004, 02:50 PM
Thanks for all the input.....a question to LawnCrafter tho.....I wonder why all the electrical stuff is so expensive?....I was planning on getting the stuff from advance auto...I guess it's a good thing people here seem to think I should stick w/ the mechanical blade engagement instead of the electric clutch....By the way did you notice a large increase in performance w/ the additional HP?...Was it a significant difference?

Fareway Lawncare
03-08-2004, 02:54 PM
Hey PaulJ, how is that Ogura clutch holding up on the SWB? I had allot of problems w/mine on the Toro's especially after I started running doubles.

Andyinchville, another thing to consider if you try & add a 23 or 25hp electric on the 48" TTHP is the added weight. One of the things I like about the TTHP's over the Tracers is their lighter weight makes them a better fit for small res. props. I would go w/the 19hp twin Kaw non-electric if such a beast exists.

03-09-2004, 12:03 AM
Andy, I say go for it. first of all the weight is a non issue. I can't speak for Kawi but I just looked in the catalog at Vanguards and the 16,18, and 20 hp's all weigh 110#. The 23 hp weighs 100#. Even if your new engine weighs 20# more, so what? (IMO)
I also say put on the clutch if you're willing to spend the money. I like clutches because they act as a positive blade brake and you don't have to adjust the belt as often. I bought a new Howard Price wb ten years ago. It was an ok mower(OK it sucked) untill I did my own modifacations to it. I put on a bigger engine, sped up the hydros and the blades, added weight to the deck, put on bigger rear tires and now I would put it up against any wb. Btw, if you do decide to put a clutch make absolutely sure to use machine bushings above and below it so that it can't move up or down at all. I learned this the hard way.

03-09-2004, 08:23 PM
Well like I said, I'm still in the process of putting the new engine on, so I haven't tested it yet. Actually I just havent had time to get to it.
The mower was pretty underpowered int he first place, so I'm sure it will make a big difference. Not only is the horese power more, but the torque is a lot more!
The 15 & 17 hp kawasakis are 500 series engines, once you jump up to a 600 series, 19 hp and up, the torque numbers jump a lot. There is a 19 hp recoil start available, but it's actually still a 500 series, not the same engine as the 19 hp electric start. So it's really not that much more powerful than the 17. I figured if was going to have to buy all the electric start stuff anyway, might as well get the 23.
I'll let you know how well it works once I get around to it.