85 Marathon predator swap

[DirtaySteve]

Hello to anyone who finds this,

I have an 85 Marathon, have been having issues with it, compression only at 80psi, leaking crankshaft seals, generator needs repair, mounting bracket for generator has broke twice and snapped the bolts that mount to the motor. Rear differential is grinding, and leaking gear oil. Just one thing after another.

Anyway, i am looking at doing a 420 predator swap, with new clutches and a FNR gear box. Im trying to figure out the best route to go for the rear end, looking at a live axel setup with disc brake system. I use the cart at work to get from job to job and carry tools. Plant speed limit is only 7, but I do speed most of the time.

If anyone can help point me in the right direction for the swap itself and possible ideas for the rear end I would greatly appreciate it.

[slonomo]

Is your engine mounted sideways with the crankshaft pointing to the side of the cart? If so, this will be a more difficult swap. You'll likely have a bunch of fabrication. If it were me, I'd find a 4 stroke cart that has a blown engine and swap into that, much easier and more reliable. With that said, you can do what you are thinking with the live axle, you'll just have a chain drive and all the issues that go along with that.

[Dabble Inn]

The 85s still have the crank pointing forward to rearward....

I like the 420 engine swap idea except for I like having reverse better, it'd be a lot less work to rebuild what you have. Good Luck

[CP241]

I second rebuilding. The 2 stroke carts it’s always better to rebuild what you’ve got if you can.

Finding a blown up 4 stroke cart isn’t that easy either. Nor cheap nowadays...

You’ll easily have $700-800 into swapping a 420 into your cart once you factor the motor, clutches, belt, misc parts, etc. plus a ton of fab time.

You could buy parts to rebuild for way less than that, and then also save a ton of fab time. And keep your reverse. Plus in terms of value, the cart is worth twice as much with a well running stock engine than it is with a predator swapped in. If you’re tired of the cart you could always sell it and buy something newer with a 4 cycle motor. If it runs well you would probably just about break even.

[DirtaySteve]

Thanks for the input guys, I almost have my employer convinced to cover the cost of parts either way it goes. I am leaning thorns rebuilding the 2 stroke and not worrying about the swap. Less head ache. Having trouble finding a full upper rebuild kit that isn't on back order.

[CP241]

Unless it’s got bad scoring you would probably be fine with a dingleberry hone and new rings.

Parts are hard to find ever since covid for everything...