Help!! Max ii loosing power when under load

[Mitchman2834]

Hey guys,

I just rescued a Max ii out of a barn after sitting for 9 years. It's serial starts with 93 something. Anyways when I'm pulling a cart or have something loaded into the back of it, I will be running at full throttle and it just kind of stops. The motor is still fully wrapped but the machine itself just stops. I'm not sure if it's just does not have enough power I have a 16 hp vanguard or if there is something wrong with the Motor or transmission. I changed all the fluid on the transmission and included the differential slip liquid this seems to have made it worse.

Before I started it after pulling it out of the barn I put a new carburetor, new spark plugs, oil change and regulator. I have checked to make sure the unit is firing on both spark plugs. Any help would really be appreciated.

[Mike]

Hey Mitchman, welcome to the forum. When your Max does that, push forward hard on the sticks. Assuming that you have springs on the laterals (control sticks) that keep them in the forward position, often the tension of the springs alone is not enough to keep the transmission fully engaged under a heavier load. Give that a shot and see if it helps. You can also check to make sure your belt is tensioned properly and not slipping under heavy load but try pushing on the sticks first.

[Mitchman2834]

Hey Mike,


So I have defiantly tried pushing forwards. Not sure if mine has those springs, when moving on flat ground I do not have to hold the sticks forward to move. I have found I have to step it up hills kinda go side to side like a cow climbs a hill rather than straight up! Let me know.

Speaking of the belt, wouldn't I hear it slipping or no? How much play should there be in the belt when it's stopped and powered off? I did notice a small crack in the otter portion of the belt but it seems fine. Suggestions?

Also where is the best place to get parts for these things. I know for a fact I need some next axel bearings. I'm located near Pittsburgh!

Thanks for the welcome!

[Mitchman2834]

Another thing to add is the engine is slightly further back on the cassis on the side with the belt than the other. Not sure if it should be exactly level or not. Thanks for the help!!!

[Dw89xj]

Hey Mike,


So I have defiantly tried pushing forwards. Not sure if mine has those springs, when moving on flat ground I do not have to hold the sticks forward to move. I have found I have to step it up hills kinda go side to side like a cow climbs a hill rather than straight up! Let me know.

Speaking of the belt, wouldn't I hear it slipping or no? How much play should there be in the belt when it's stopped and powered off? I did notice a small crack in the otter portion of the belt but it seems fine. Suggestions?

Also where is the best place to get parts for these things. I know for a fact I need some next axel bearings. I'm located near Pittsburgh!

Thanks for the welcome!

I bought my bearings, chain, and bushings from buffalo bearing. They were real pleasant to deal with and took just shy of a week to ship to a little south of Harrisburg. (716)874-1720 is their number, I dealt with Greg, he was real cool. Other parts I was lucky enough to get from other members on here, craigslist, and eBay.

[Mike]

Yeah, you will want to get the engine as straight as possible. I'm not saying that is the cause of this problem but you do want the CVTs as straight & inline as possible. Since you have tried pushing forward hard on the laterals and that didn't help, I would move to the belt next. There is a manual on the front page of the forum here that you can reference: Max 6x6 Manuals Check both the belt tension and the belt width. If the belt is less than 1-1/16" wide, get a new one. As far as the tension, the manual calls for 1-3/4" deflection when you press on top of the belt with one finger. Page 94 of the manual will walk you through the adjustment procedure if needed.

Also, do you know if the 16HP motor was the original motor in the machine? If it has been swapped out, you could possibly have the wrong clutches for that motor. Another possible issue is that your transmission bands need adjusting. The manual should cover that adjustment as well. Again, start with the belt and go from there. Good luck!

[Rusty-Gunn]

Max6x6.com | Max 6x6 Atv Parts | Max Amphibious ATV| Max Atv Accessories for Max parts

[hipowerone]

You came to the right source for information on your problem. I had a similar problem just over a year ago with my MAX II 14HP unit....after checking here, I took the advice of checking belt tension and engine alignment....that was the problem and I have not had a "power" issue since. Note, the manual says the drive belt width should be a minimum of 1 1/16". New belt specifications say that they measure 1 3/16", but the two that I purchased recently come in just a hair over 1 2/16", not quite 1 3/16". According to a contact that I had, new belts are being shipped a bit undersized....maybe to save money?? While you may hear an undersized belt slipping, odds are you will not, though you may smell burning rubber if it is slipping.

[Mitchman2834]

Thanks guys for the info!

This has been a great help to get me on the right path!
I have seen a couple different belt replacements other than the one for $77 on max 6x6.com. Has anyone tried the Dayco HP3003? Or I believe I saw a gates part number floating around as well.

Also I was reading the valves can sometimes cause this issue is it worth just adjusting those anyways or am I asking for problems by opening up the valve cover?

[Reconrokon]

Thanks guys for the info!

This has been a great help to get me on the right path!
I have seen a couple different belt replacements other than the one for $77 on max 6x6.com. Has anyone tried the Dayco HP3003? Or I believe I saw a gates part number floating around as well.

Also I was reading the valves can sometimes cause this issue is it worth just adjusting those anyways or am I asking for problems by opening up the valve cover?

The Dayco HP3003 is the correct belt for a Max II. I ordered one from Sixity.com for $33 and free shipping. Exact same belt as the original factory belt that was on mine.

[Noel Woods]

Check the engine compression as well. The little B&S motors age poorly.

[Mitchman2834]

Hey guys just an update, I have a new belt on order, I'm in the process of adjusting the transmission tensioner. The right side seems to have the top screw is almost all the way out. Do you think the old owner did this for a reason or is it just negligence?

I figured I would adjust the chains as well on the jacksprocket, I have found on the one side someone used a hook in place of the correct chain tensioners and it looks like the chain running from the top sprocket down to the bottom sproket wants to slip off but never actually does. So when the wheel is turned while jacked up I am getting a slight pop and I can see the chain almost slip off the sprocket but it pops and stays on.

Is this usually an issue with the sprocket or the chain or both? Thanks a million!