Sparky & All,
(This got way too long to snipe anothers thread so I posted anew here).
Sparky wrote:
" I do not know as of yet how to change the RPM's on a Diesel but I would like to run this at the lowest RPM possible within reason of staying effecent and dependable."
There should BE a throttle somewhere! Follow the fuel injector tube from the cylinder head back to the pump. Somewhere on the pump there should be a moveable lever attached to a rod/shaft to control the amount of fuel pumped to the injector. Moving that lever one way or another allows more fuel to be pumped to the injector. That's the throttle control in a diesel. Govenors are USUALLY interal to the pump. That's how one controls the RPM and usually stops the engine. There should be an adjustable "stop" to limit high RPM at full throttle. Diesels are pretty straightforward this way. The only other way I know of to stop a diesel engine other than by fuel shuttoff is by air denial. With air denail the injector pumps raw fuel into a dead cylinder, which aint good. I've never seen it used on a diesel and only know it can be used in an emergency pump runaway situation.
You might want to "play" with the RPM/Amps out until you find a sweet spot these engine like. Too slow with very little load may lead to too cool operating temp. Lubricating oil must reach a given temp to be really effective and you engine's upper end may carbon up at too low RPM. Diesels run way cooler than gas engines. A good temperture gauge is a must for reliable long life in a diesel. If these are air cooled engines it is still a good idea to monitor the engine temp. Finding that sweet spot is a factor of engine temp and will change with the seasons. I like to see my engine running at about 180° F.
Running too high RPM cost fuel and wears the engine faster than it should. The RPM control should be a function of a position to the injector pump control rod/lever. Are these direct injection engines, does the diesel get injected straight into the cylinder? Custom exhaust can help with the noise a bunch and gets rid of the soot any diesel spews. If these are air cooled they will have more "rattle" than a liquid cooled engine, but sound insulation in the engine room can help there a lot. The 350' distance will help there a lot too.
While my Kubota® isn't 350' away it is 75' from the house in its own building. I use relays, negative side driven, and push button switches for start. throttle up and down, and the glowplug. Charge enable is a STSP to another relay. I supply positive DC to the relays actuation coil which are near the battery bank, and the in-house switches complete the circuit for said relays. I feel most of the voltage drop is on the backside in my arrangement as they work very well. Whether you can make that work at 350' is one of those maybe deals. Maybe look at a remote wireless starting system made for a diesel! Or maybe use 110V ac relays or 5V dc relays with limiting resistors.
If these engines have glow plugs then winter startng should be easy. NEVER ever never use starting fluid. Small diesels don't like it when before top dead center detonation happens at all and diesels have a compression ratio high enough to make that ether explode way too soon. Starting fluid might blow the engine in one crank. If these are without glowplugs an intake air preheater may be needed. Warming the intake air just a little helps a bunch with cold weather starts. Also if these have a compression release use it in cold weather. Get the engine spinning full tilt with the compression released and then suddenly close it. I've had to start my Kubota down near zero F and it can be tricky. All I can say is don't rush it. If it doesn't fire right off let it "rest" a few and try again. I have propane torch warmed my egines' head for several minutes prior to an anticipated hard start. When you gotta have engine power you gotta make it reliable as hell or learn to improvise like McGyver. In the later case a simple old fashion oil lantern, metal type, under the engine stand will work. Keep the wick low and make sure the fuel hoses don't get too hot. Inside an enlosed room that heat will really help. Keep the diesel from gelling, also very important!
Oil leaks or seeps? There is a big difference. A seep might let a 1/4 ounce of oil by per change period. A leak could drain the engine in less than an hour. Either way it's messy and expensive sometimes engine rebuild expensive. Also either way new seals and gaskets can stop them. Unless you have broken castings which I doubt. If these have spin on filters those might be old and messing with the pressure relief, if so equiped, raising the oil pressure too high. If the pressure relief valve is internal it might need checking out. Be sure there's not too much oil in the crankcase. Is the crankcase breather open? Dirt nesting wasps, or "dirt daubbers" or something could have plugged/obstructed the breather tube. Were they using synthetic oil in their previous life? If they run good the oil can be stopped fairly cheaply whatever the reason. Lastley check for excessive ring blowby. If, when running, the crankcase breather tube is puffing really hard in relation to the exhaust note, or in time with the power stroke, that can force oil past seals and such and really pollutes oil FAST. A copression check can verify/deny such blowby.
Find a way to monitor the oil pressure with a fairly accurate gauge. I like mechanical tube type gauges for temp and oil pressure.
If I had 4 of these engines I'd buy a shop manual and set about making one like new while using another. I'd keep 2 as spare parts. When I finished restoring the one I'd put it into service and do another. I'd love to have another Kubota in new condition as a backup to one in new condition, with two more as backups to those. Jez:)
My First Kubota® EL-300-E was Over $1550 six years ago and a wife is moaning about $800 for 4 engines? Hmmm. I must have a keeper then ( NOT that Sparky doesn't ) 'cause mine never had a problem with that Kubota®. I bet these engines of Sparkys cost WAY over $800 each when new! I would also bet you he could sell one for $400, as is, real easy. I found a surplus US millitary Kubota® 300 series motor for $250 but it was minus MANY parts I had already from the first 300 series engine. I thought I did good, doooh! 
Yeah, Sparky made out like a bandit. Congrats!!
