speed up Lazer?

[Brian Taylor]

I have an 04 lazer with a 23 kohler and was wondering if there was any way to speed it up a little. (adjust linkages?) It is a little slower than our grasshopper. It is not a big deal but every little bit of production counts. Thanks for your help.

[eXmark]

Brian,

There's really not much you can do. What I'd recommend is to check to make sure everything is doing what it is supposed to. First I'd check the enging rpm to make sure it's running at 3600 3750. I'd also grease the life out of the pump drive idler to make sure it's pivotiong properly and that the belt isn't slipping. I'd also look at things like tire pressure. The Lazer really likes about 16-18 psi. in the rear drive tires.

Thanks

terry

[John Gamba]

Originally posted by eXmark
Brian,

There's really not much you can do. What I'd recommend is to check to make sure everything is doing what it is supposed to. First I'd check the enging rpm to make sure it's running at 3600 3750. I'd also grease the life out of the pump drive idler to make sure it's pivotiong properly and that the belt isn't slipping. I'd also look at things like tire pressure. The Lazer really likes about 16-18 psi. in the rear drive tires.

Thanks

terry

How About some sort Of TURBO!!!

[eXmark]

Johnny,

The Turbo would be nice and it would make sense in a lawnmower application but the valves on most of these engines start to float at about 6,000.

Thanks

Terry

[Cutters Lawn Care]

I have a 02 lazer z hp. manual says 13 psi in rear drive tires is this correct.

[John Gamba]

Originally posted by Cutters Lawn Care
I have a 02 lazer z hp. manual says 13 psi in rear drive tires is this correct.

Thats what i think 13psi????????????????? Terry.
John

[eXmark]

Cutter,

13 psi is a good starting point and works well form most applications. If your in hilly terrain 16-18 gives a little better traction.

Thanks

Terry

[John Gamba]

Originally posted by eXmark
Cutter,

13 psi is a good starting point and works well form most applications. If your in hilly terrain 16-18 gives a little better traction.

Thanks

Terry

Cool!

[DieselDeere]

Originally posted by eXmark
start to float at about 6,000.



What does that mean?

[jajwrigh]

Valve float is a situation that occurs when a specific rpm level is reached and the valves "float" open. This situation makes the intake/exhaust relationship very lopsided. This results in a loss of power and could potentially damage the engine. The suggestion about a turbo was denied because turbos love to create boost at high rpms (boost creates more power by forcing air into the engine) and the exmark's engine's valves float before effective "boostable" rpms can be reached. I hope this makes sense...

[eXmark]

DD,

There's a generational thing. My generation grew up on Hot Rod magazine and thus know terms like valve float. Todays youth is gowing up on video games and TV and understand how to use their computer.

Good thing we now have "Monster Garage" so all generations can gain useful knowledge (such as how to build a car out of a boat) that can be used throughout life.

Just having fun.

Have a good weekend guys.

Terry

[John Gamba]

Originally posted by DieselDeere
What does that mean?

Diesel
They go up an down so fast! they seem to stay in the middle.

[1acreplus]

Ok, so I'm 28, I guess that qualifies me as still younger than a good bunch of guys on here... And I know who Rat Fink is, too. ;)

Here's a little story about when I learned the hard way what valve float is. Perhaps you'll learn from it if you're "Today's youth", or see a little of yourself in it, if you're old enough to know better. :)

There was a pretty good description above, but simply put, valve float is what happens when the valvesprings fail to keep the lifters (some folks call 'em tappets) against the cam lobes. When the high side of the lobe comes back around to meet the lifter on its way back down the hole (usually at extreme RPMs), bad things happen.

In my teenaged years, I was goofing off one weekend, and a buddy and I decided to build our own portable generator using a 2.5L inline-4 chevy motor we salvaged from an early 80's econo-car and a belt-driven generator. We didn't pay careful attention to the calculations for engine speed v.s. generator shaft rpm... (using a belt/pully setup for RPM reduction). The only tach we had was at the generator shaft, so without a whole lot of thinking, I overspun the motor.

Guess what happened... yup... The valvesprings on this tired little four-popper couldn't keep the lifters safe and sound against the cam. In shorter words, valve float.

Good thing I was in front of the mess instead of beside it. What came next happened in a split second. One of the connecting rods went straight through the oilpan, and managed to take a fist-sized chunk of the block along with it. A small piece of the crank that snapped off punched a hole straight through the 1/8" plate steel that was the floor of the trailer we had this setup on. Had it not been for the quick thinking of my buddy, who yanked shut the fuel line in a big hurry, there probably would have been a collosal fire, too.

Moral of the story - governers and/or rev-limiters are good things on engines of any size, and so is a tach (that's working properly!). Spin an engine too fast, and you'll be lucky to tell about it later.

And when the manufacturer says "no turbo" and "don't go over X RPM", you had just better take their word for it. Pressures in engines can easily hit over 100,000psi. That can send parts through your body like bullets if something goes wrong.

Another way of thinking about it is like this: Your mower isn't a drag racer - it's about endurance. It might be nice to go zoom-zoom, but you're not going to make the motor last 500 laps that way.

[MikeLT1Z28]

so you are saying the rest of the components and bearing will hold up to that rpm? hmmmmm 5500 sounds good to me!

[eXmark]

Mike,

I didn't say that..........no not me. One would assume that like anything it'll hold up for a little while and then things get real expensive and as 1 Acre put it. Dangerous too.

Thanks,

Terry

[DieselDeere]

Thanks, I got it.

[eXmark]

DD,

Thanks, that was a great deal of fun actually. The the valve float description was pretty cool. Now if I only had that new Ford GT I could go play Hot Rod instead of talk hot rod.

Have a good one.

Terry