John Deere 420

[Yellowfever440]

Hi everyone, thanks for any replies I recieve, I am still trying to search the forums for any information on the 420 garden tractor. Anyone's advice, tips or opinions are welcome.

I have always wanted a 420 for the 2 speed and the 3 hydraulic valves. I found one and the person I spoke with has the trator with a deck and a second parts deck. He has it listed cheap because it has some engine trouble, he thinks it has to do with the governor possibly but it runs and he said he doesn't know what it is for sure but it seems low on power and he think it runs too high of rpm at idle. I don't know what all he has tried but it does have 1350 hrs on the Onan 20 hp motor. Are those tractors worth the size and all. I'm not worried about it being too big I have an x585 with a loader and snow plow but I have always wanted one and his price is lower for a reason and I don't mind working on them. The x585 doesn't have the 3 scvs and I know people are adding valves to them, but I have a pull grader box and it would be nice to have the second tractor for odds and ends and mowing another property.

This 420 is an hr away or so and it's close to the right price but I think the Onan start to give up around the 1500 to 2000 hr range, I had a couple of 318s and I wish I never sold either one but too late for that now.

Any thoughts on any thing I have said.

 

[buickanddeere]

The 420 is not the only JD large frame garden tractor with those options .TractorData.com John Deere 42 tractor information

 

[Yellowfever440]

The 400 which power assisted steering and the 430 which is diesel and has the extended nose. Is that all of them or are there others?

 

[8hlutt]

The 400 is the predecessor to the 420. The 420 and 430 are essential the same tractor except the 430 is diesel powered. I have both tractors and love them both, except for the hand controlled group speed lever. My 420 recently had what sounds to be the same issue with what I thought was the governor but later found out the cam bearing were trashed at 1800 hours. My solution was a repower Briggs and staton kit from small engine warehouse. Easy to install and everything seemed to work as it should. If you liked the 318 you will love the 420. It is essentially a larger version of the 318.

 

[Yellowfever440]

Are the camshaft bearings replaceable or was the rest of the motor enough it wasn't worth fixing? I see you can get a 23 hp Briggs vanguard for $1750 with the install kit. Any other major problems to look at if I go look at this tractor?

 

[Kish318420]

Yes cam shaft bearings are replaceable, but it will require a pull out and partial tear down of the engine, but since you are in there, you might want to check the cylinder bores with a gauge, because the cylinders are horizontal they tend to wear like an egg in shape. This will help determine what shape the engine is in.

1.) compression check
2.) leak down test
3.) remove heads, visual check/inspect also use gauge to check wear of cylinder bore

Just don't throw parts at it. A certified small engine mechanic can be a great help, along with a engine shop with the right gear. Do your home work and check, double check, triple check. Don't be taking in by low prices, it could and probably cost more in the end going that route. I know by personal experience.

 

[Yellowfever440]

Do you think the Onan will run a while longer if I tear it down and just rebuild if needed compared to a Briggs vanguard? I think Briggs and Stratton engines are decent but I don't know how well they do when used hard. Most of the time it won't be used all that hard. If I bought the vanguard replacement I would have roughly 3200 in it total.

 

[8hlutt]

I would have preferred to have my Onan rebuilt but mine crapped out in the middle of June when the grass was growing so fast you could almost watch it. Lol. So I had to go with the fastest way to get mowing at the time. The vanguard kit came with every thing I needed to install and get running. Had to make some minor modifications to the choke and throttle cables but nothing major at all.

 

[Yellowfever440]

Why would you of preferred to rebuild the onan?

 

[8hlutt]

To keep the tractor original. Considering it is in nice shape for its age. But if that doesn't matter than the Briggs is a good choice.

 

[Yellowfever440]

I was thinking I would be able to purchase the 420 I found and just have to replace a few things. But I would probably open it up and find more wrong with it then I would want and I would end up replacing it or over hauling it which wouldn't be cheap either. I am fine doing the labor myself I have done a few 318s but it's just the fact in an parts have gone up in price. Maybe it is still worth it though because the 420s that are priced higher still have a few hours on them where anything could go wrong.

 

[Kish318420]

A proper rebuild and maintained onan will probably out last any other engine I got 3000 hours (29 years) out of mine, now I hope to get another 3000 hours. Hopefully parts will still be available for the rest of the tractor.

 

[ovrszd]

My Son wore out his Onan. He replaced with a Honda V-twin. Bolt in kit with all the accessories. It's a whole different machine now. I think it actually speeds up the blade tips slightly. It'll mow however fast you can ride the seat. I can't remember the exact cost but want to guess around $1200. After seeing his, I'd not spend much money on an Onan rebuild.

Good luck with your project and choices!!!!