John Deere 425 Loosing Power

Whiety · Apr 28, 2018

Hey guys.

I am trying to figure out what is wrong with the wife's tractor. This is a early 90s 425 all wheel steer with a54" direct drive deck. I put it away last year and was fine. Took it out this year and checked the fluids, cleaned the filters, pulled the deck and sharpened the blades. After starting I went to engage the deck and the tractor had trouble making it turn. So I looked and the belt looked loose so I bought a new one and tried again.

Same thing. Mower is running slow and the tractor is laboring to make it run. No high RPMs when running so what am I looking for?

BTW.....the tractor when running without the mower seems louder this year? Like the muffler is going bad?

Seems to me there is something amiss with getting power from within.

Perplexed in Slippery Rock.

kthompson · Apr 28, 2018

If gas, do you use ethanol free? Regardless the fuel type try fresh fuel, check for water in it. Replace fuel filters. Check air filter and air intake for insect or mice nest restricting air flow. It is possible the muffler has rusted to point it is blocking the air exhaust hurting you. That would explain the louder part. Last thought I have is check for bad bearing in the system for the blades when you engage the cutter.

tomplum · Apr 30, 2018

I wonder if it is running on 1 cylinder? IE 1st guess stuck valve/ bent push rod. Or a mouse got into 1 sides wiring. Or a bad spark plug for that matter. Run it up for a few minutes and see if both exhaust pipes are hot.

Whiety · May 1, 2018

OK.....fixed that problem. I identified that the drivers side cylinder was not firing. So I bought two new coils ??? Pulsators ?? IDK......but changed them and the plugs and the boss is happy again.

At least for now.:thumbsup: