Normal speed?

[ARGOJIM]

Looking at the pictures the belt has some wear I'd start there if you can't find a mower shop to test the rpm's. I'd like to say something about the clutch but that will wait.

According to an older brochure the 16 Tecumseh IV tops at 20 mph, however there were 3 tire options available ( the 21, 23 and 26 ) and not sure as to top speed per tire or which does 20 mph. A 26 will eat a 21(closer to 19.5 or so on 8x8 rims) for lunch on flat ground.

[martin_andy25]

Thanks Jim, and please feel free to say what u want about the clutch, I need all the help I can get. Can I just cut the belt off and take it to a mower shop and let them give me the same one or since it has wear will it be stretched and measure wrong?

[ARGOJIM]

I'd suggest a new belt from the factory or an aftermarket belt that msafi65 posted the number of.
I'd remove the belt and learn the trick (if there is one) so you can put the new one on without damage.
Take a picture of the new belt in the drive clutch before I comment.

[martin_andy25]

Ok will do! thanks everyone for the replies!

[martin_andy25]

ok so I got a new belt and it didn't help my speed at all. Any other suggestions??

[Mike]

Did you make sure that the new belt was tensioned properly by placing shims under the motor if necessary?
How much movement do you have in the new belt if you squeeze it together between the two clutches?
Did you ever check the RPM of your motor?
Have you had someone rev the motor up in neutral while you watch both clutches to make sure they are engaging properly?
When you are testing the speed, are you pushing forward on the sticks hard to make sure that the T20 is fully engaging?
What are you using to check your top speed?
Have you checked the band adjustment on the T20?

[ARGOJIM]

We are all going to tell the same thing, rpm's is the first place to start with top end speed. IE. if you are getting 3/4 throttle you may get 3/4 speed.
I have a machine currently fighting me at 2800 rpm and if I get 10mph it's a lot, and that is on a II.

[riotwarrior]

an advance adjustable timing light will have an tach so you can test rpm via that if need be...just connect the inductive pick up to the spark plug wire and golded ye be!

ensure that with engine OFF the throttle can and does open fully and choke isnt sticking.

make certain belt tension is correct.

watch belt or have someone watch it and ensure clutches are going to full hi speed may want to block jnit up to test this I do not know if uou can test parked.

if clutches function correctly and throttle opens fjlly en maybe that is all yer machine has....if so clutch change may help but not much


good luck...remember these are NOT designed for speed...

[akcrawler]

I have a new machine with 21" tires so I can run tracks and it tops out at about 15-20mph. I am sure I could get another 5-10mph with the bigger tires, but I bought it to cross rough stuff and marshy areas. Most of the time I run in those conditions at around 1/4 throttle. I would like to try some of the larger tires some day, but practical applications for speed are really limited where I ride. I want the larger tires for reduced ground pressure so I can stop using the tracks in the summer, not top speed. I guess the top speed enhancement would be kinda fun for running up an down the dirt road in front of our house...hmmm! At least the rest of the guys gave you some good things to check, but if you have the smaller tires you probably won't get a lot more out of it.

[Mike]

I have a new machine with 21" tires so I can run tracks and it tops out at about 15-20mph. I am sure I could get another 5-10mph with the bigger tires, but I bought it to cross rough stuff and marshy areas. Most of the time I run in those conditions at around 1/4 throttle. I would like to try some of the larger tires some day, but practical applications for speed are really limited where I ride. I want the larger tires for reduced ground pressure so I can stop using the tracks in the summer, not top speed. I guess the top speed enhancement would be kinda fun for running up an down the dirt road in front of our house...hmmm! At least the rest of the guys gave you some good things to check, but if you have the smaller tires you probably won't get a lot more out of it.

Going from 21" tires to 26" tires will increase your top speed by 124%. So if you were getting 20mph on 21" tires, you should see 24.8mph on 26" tires.

[ARGOJIM]

Going from 21" tires to 26" tires will increase your top speed by 124%. So if you were getting 20mph on 21" tires, you should see 24.8mph on 26" tires.

Not an engineer at all but think I can add some, would you explain or correct the 124% for us.

[Mike]

Not an engineer at all but think I can add some, would you explain or correct the 124% for us.

Definitely question any math I throw out. I've calculated that I'm right 64.2% of the time.


For the speed, it's simply the ratio of the tire diameters. Take the new tire diameter and divide it by the old tire diameter. Multiply that by the old speed to get the new speed. In this case 26/21 = 1.24 or 124% 1.24*20mph=24.8mph

I made the assumption that a 21" tire is actually 21" in diameter and that a 26" tire is actually 26" in diameter. While we know that's not exactly right, it's close enough.

[whipper-ag]

[ARGOJIM]

Thanks Mike, I was adding 124% in my head giving me 44.8 mph and went, huh?

[mfenmor]

My Max IV with 26" tires and Kohler 20 turned to 4000 RPM only does 26 MPH! GPS is wonderful.