Author Topic: Kubota EA300  (Read 1526 times)

Tanman

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Kubota EA300
« on: October 23, 2019, 02:40:15 PM »
There are three of these Kubota EA300s I have found for sale in my area for around $300-$500. Seems like a good deal, does anyone have any experience with them?
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old seagull man

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Re: Kubota EA300
« Reply #1 on: October 23, 2019, 05:38:54 PM »

Tanman

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Re: Kubota EA300
« Reply #2 on: October 23, 2019, 06:25:31 PM »
Thank you.
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hwew

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Re: Kubota EA300
« Reply #3 on: October 24, 2019, 05:05:23 AM »
Just updated the links for the service and parts manuals.

http://www.microcogen.info/index.php?topic=542.0

The original links would not open.
They should open up now.

Henry
« Last Edit: October 25, 2019, 08:26:59 PM by hwew »

hwew

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Re: Kubota EA300
« Reply #4 on: October 25, 2019, 09:13:12 PM »
The EA300 and EA330 engines are some of my favorites. Had one of each and they loved running between 2600 -2800 rpm. My opinion is both engines had more fuel knock below 2600 than I liked.

The EL300 is another one. They look almost the same.
The maximum rated rpm is 2000. I do know they are timed 22deg. BTDC. Probably to help with less fuel knock at lower RPMís.
There might be some internal differences. Never saw the inside of one.
The EL300 would be the one to find if someone is planning to build a small slow running genset.

The EA300 might be able to run at lower speeds like the EL300 by Setting back the timing 3-1/2 degrees. And setting the governor speed to 2000.
« Last Edit: October 25, 2019, 10:43:45 PM by hwew »

Tanman

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Re: Kubota EA300
« Reply #5 on: February 03, 2020, 02:29:43 AM »
I picked up a EA300 for $300, tore into it today and found that one of the valves wiggles a fair amount and the valve seat has worn a little. I have the manuals and part numbers. It seems like parts are a little tough to find, is my best shot my local Kubota dealer hunting some valves and valve guides for me?
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hwew

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Re: Kubota EA300
« Reply #6 on: February 03, 2020, 12:12:03 PM »
That might be your best bet. Kubota should be able to get them. While you have it apart it would be a good time to check the cylinder bore and if itís within spec hone the cylinder and re-ring the engine.

Just in case the bore is out of spec. There is an oversized piston and rings available.

Which guide is worn?

Do you have any idea of the hours on the engine?

Henry
« Last Edit: February 03, 2020, 12:29:52 PM by hwew »

hwew

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Re: Kubota EA300
« Reply #7 on: February 04, 2020, 01:49:44 PM »
Tanman, Just received a call from a friend in Jacksonville Florida that runs a shop that makes compact diesel generators for sailboats. They use Kubota engines only.

He knows the EA300 and EA330 very well. The company made Hundreds of units with those engines.
We talked about your situation and he explained to me that itís normally the exhaust valve guide that will get some wear over time. The intake valve guide normally donít give any problems but since the engine does not have valve guide seals there is a possibility of having oil sucked around the intake guide if itís very worn. This situation can be made worse with oil getting past the piston rings and if the air cleaner is restricted. He said there has been a few known cases of runaway engines but very rare.

He mentioned to replace valve guides, check valve stems and seats for wear, check cylinder and re-ring it and make sure the breather is functioning properly.

He mentioned that a good machine shop should clean up the seats. However the heads are known for rusting through on salt water applications so if it was a salt water engine check out the head thoroughly. If the head is bad a new one is available but itís around $500.00.

When I was visiting him years ago I saw a whole bunch of EA300 heads on a table that were just rebuilt. I ask him about those and his response was the market pretty much dried up. At times they good ones on eBay for rebuilding.

Henry

« Last Edit: February 04, 2020, 01:52:35 PM by hwew »

Tanman

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Re: Kubota EA300
« Reply #8 on: March 10, 2020, 03:03:13 AM »
Thank you very much Henry, I have just ordered the parts you suggested! I will need to have the valve seats cleaned up for sure. No salt water damage but some damage from the loose valve. Thank you for the information, it helped me out a lot!

Question for folks with more experience, Iíve only replaced piston rings once on a 2-stroke four wheeler and havenít de-glazed a cylinder before. Should I give it a go or have a shop do it?
« Last Edit: March 10, 2020, 03:05:28 AM by Tanman »
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snowman18

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Re: Kubota EA300
« Reply #9 on: March 10, 2020, 04:10:14 AM »
Thank you very much Henry, I have just ordered the parts you suggested! I will need to have the valve seats cleaned up for sure. No salt water damage but some damage from the loose valve. Thank you for the information, it helped me out a lot!

Question for folks with more experience, Iíve only replaced piston rings once on a 2-stroke four wheeler and havenít de-glazed a cylinder before. Should I give it a go or have a shop do it?

if you have chrome moly rings I would let the shop do the work.

Read the full article, https://www.hastingspistonrings.com/tech-tips-faqs/cylinder-bore-refinishing

Cylinder bore refinishing is extremely important in the engine rebuild process. There are some basic rules and facts that will prevent common problems incurred when deglazing or refinishing cylinders.
Cross Hatch Angles

The correct angle for cross hatch lines to intersect is approximately 45 degrees. Too steep an angle promotes oil migration down the cylinder resulting in a thin oil film, which can cause ring and cylinder scuffling.

Too flat a cross hatch angle can hold excess oil which conversely causes thicker oil films, which the piston rings will ride up on or hydroplane. Excessive oil consumption will result.

The diagrams will illustrate cross hatch angles.

hwew

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Re: Kubota EA300
« Reply #10 on: March 10, 2020, 04:28:54 AM »
Very well said snowman18,  it would take an engine rebuild shop to do it right.

Henry

glort

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Re: Kubota EA300
« Reply #11 on: March 10, 2020, 11:07:32 AM »
Question for folks with more experience, Iíve only replaced piston rings once on a 2-stroke four wheeler and havenít de-glazed a cylinder before. Should I give it a go or have a shop do it?

If you are only fitting new rings and not doing a rebore with an over size piston, I have to say I'd just give the engine a hone myself as I have done with many engines I have rebuilt. I have used those honeing tools you put on a Drill and sat them  with the bore propped up in  a tray of Kero or Diesel ( or just sprayed loads of WD or something as I went ) and I have never had any problem getting the right Cross hatch angle.  To me, just seems to pretty much do it by itself if you use a steady drill speed and a regular up and down motion. You HAVE to make sure you go all the way to the ends though so as not to barrel the Middle. Thats where you want to take as little material from as possible.

Myself, I have had no trouble with this and am a little surprised at the Importance others have mentioned.  In my experience, as long as you make sure to get that top lip out the bore and not to add any more barrelling to the bore, they work fine.  Can't say I have ever noticed an oil thirsty engine after a rebuild.

I have also on a couple of occasions  re sized cylinders with a hone  but I sure wouldn't recommend that. Takes forever and by the time you replace the stones, no cheaper than taking it somewhere although the reason I did was I needed the engine there and then and only had the over size piston and rings rather than the same size.

In my feeble mind You Freshen up an engine and you rebuild an engine.
 A freshen up is to me, done in house, Hone, lap the valves, new rings on the old cleaned up piston ( or a better used one) Maybe new bearings, lap the head if you need to... Put it back together, it runs better and get years more out of the thing.
A rebuild is sending stuff out. New valve seats, bored to oversize, crank ground etc all done by a machine shop. Basically you make an old engine like new again.... or better.

Just fitting new rings is really a bit half arsed ( although completely viable)  because they are probably already half way out in the limits when you put them in so aren't going to give the full life anyway. Getting a Cylinder professionally honed which is only going to give it more " wear" and take it closer to max tolerance just isn't worth it, to me anyway.  If you are going to put in a new oversize piston and rings, then no question send it out but as just a patch up job...  Honing tool has been perfectly adequate for me is all I can say.

Freshen up can give engines years more life and if they are only something you use intermittently, will last for ages.
If it's an engine you need to rely on for regular use, then I would say do the lot and rebuild it properly.


Tanman

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Re: Kubota EA300
« Reply #12 on: March 24, 2020, 04:06:26 PM »
Ended up dropping it off at the shop to have the valve seat repair, new valves and valve guides installed and lapped, cylinder honed and new rings, as well as a new rod bearing. Now while that is getting built, I need to figure out what generator head to slap on the things. I wish I could find an 1800rpm 3kw 1ph 115v brushless head, any thoughts?
Yanmar L100-5KW set
Chinese 1115-8KW stamford
96 Suburban 6.5 turbo