Max II with no torque

[dgroff85]

Ok everyone I bought a Max II that's been a project to say the least. My machine is a 96 with the 18hp vanguard. I understand these are not fast, but the lack of torque is rather frustrating as it won't even break the tires in going up hill in the loose stuff. The rpm range seems fine and idles well, but its almost walking speed going up hills at or climbing anything at (WOT) and maybe 11 mph on flat ground. Both primary and secondary clutches seem to work as they should. I'm lost on what else to do, everything I've done is below. What am I missing? at the point that I might cave and take it to a shop.

Work accomplished:
New belt HP3003 and tightened
Cleaned both clutches
Adjusted chains
New idle jet
Cleaned and rebuilt carb
New Plugs
New AF
Oil Change
New fuel pump, lines, filter, cleaned gas tank
Greased everything
6 new wheels and tires
New throttle cable and adjusted
New lights
Added bilge pump
Serviced T-20 with Type F

[Toys4Me]

I dont see on there adjusting the trans.

[dgroff85]

I dont see on there adjusting the trans.

I only serviced it, how do you adjust these trans? I think the machine has around 70hrs

[thebuggyman1]

I still suspect belt tension. The rubber motor mounts can be very troublesome as they allow the motor to move closer to the trans making the belt loose before the machine moves.

Try: over tightening the belt. You wont be able to shift, so start it in gear and hold back on the sticks.......See if this changes your power problem. If it does you will know it is the belt tension.

ALSO....get rid of that type "F" trans fluid....it is the lowest grade trans fluid available and even after adding the friction modifier it is only marginal....... There are lots of other ATF's meant for modern transmissions that will hold up to the heat better. I use one meant for GM transfer cases $8/qt and I also use 1 1/2 qts.

[dirtdobber]

I agree with the belt issue. It's either too lose or slipping. Make sure you didn't get any oil or grease on it when doing your maintenance.

Adjusting the transmission is also a good place to check. This means adjusting the plungers at the C Channels to ensure you are getting full tension on the bands when applying force to the laterals. If your laterals aren't fully engaging the bands inside the transmission, it essentially is the same as riding the clutch in a stick shift vehicle - things aren't fully engaged. I don't have a link handy but there are lots of posts on how to adjust.

[dgroff85]

Thanks everyone I'll give it a try.

[special ed]

just a thought when mine wouldnt climb found that I had a broken cam in the primary clutch It looked like it was working but under load wasnt had to keep playing with the sticks back and forth

[Noel Woods]

Could also be a worn out engine, if so and you are losing compression, there will be no grunt behind the power. It will make all the noise, rev like normal, but no torque. Check compression to rule this out. Briggs and Stratton is known for engineering in planned obsolescence.

[ARGOJIM]

First check your unloaded (neutral) rpm which should be about 4000.
If the engine was replaced the governor spring could be incorrect.

I'd pull the valve covers and check that all 4 push rods are in place, the engine will run descent on one cylinder with low power and someone may not sense it.

[dgroff85]

I’ve been pretty swamped working on other projects, but I moved it today and noticed it has noticeably more torque in reverse. I’m going to order the tool to adjust the trans also.

[dgroff85]

Ok, so I tried to adjust the transmission and that didn't help. There's a noticeable difference in power between fwd and reverse. To the point reverse has the power and torque I need. To me that would mean the belt and engine are good? Would this be caused by band wear? I'm kind of stumped and I think the machine has around 70 hrs on it.

[tbone9]

Try pushing forward with slight pressure on the sticks. Maybe the springs aren’t putting enough pressure on the forward bands.

[ARGOJIM]

Silly question (sometimes), is the parking brake on?

[thebuggyman1]

There's a noticeable difference in power between fwd and reverse. To the point reverse has the power and torque I need. To me that would mean the belt and engine are good?

Not necessarily. Reverse in the t-20 has a lower gear ratio. Poor belt tension and/or worn belts cause a higher gear ratio as the primary clutch is allowed to advance prematurely compared to the secondary.

Try watching this:

https://www.youtube.com/watch?v=O93KhW6pW7c

The video is about tuning clutches but you can see how the belt sticks above the edge of the secondary at idle. You should put your machine in neutral and run it through the rpm range watching how the belt advances. Notice on mine the distance between pulleys does not change.......if you have those crappy stock rubber motor mounts yours will. This screws up how the clutches work together.

[dgroff85]

Silly question (sometimes), is the parking brake on?

I wish that was it, checked several times