Tired Beaver

dadzilla · May 22, 2002

Does anyone have the specs for what compression should be for an S370D. Mine seems to have lost power over the last few years. It still runs good, does not use oil. The most noticeable thing is the need to use glow plugs in the summer with throttle wide open to start, never had to do that before. The fuel filter has been changed. Once started and warmed up it runs and starts fine other than when pulling a hill under load it huffs lots of black smoke, didn't do that before either. Thought maybe compression was getting low. Any other ideas would be appreciated.

Thanx!

Egon · May 22, 2002

My B7100 Kubota seemed to be lossing power and did not burn any oil. It started okay though. I added some fuel conditioner to the diesel tank and was rewarded with with gobs of soot comming out the exhaust on start up. This cleared up quickly and all was back to normal on the power side.
Egon

alvanko · May 22, 2002

Acording to the service manual the compression pressure is to be 455 lbs/2 at 380 rpm's . It also states that 312 lbs/2 is the lowest acceptable pressure . The compression ratio is 20-1 . I have the service,parts,and operators manual if you need any more spec's or help . Just ask .

dadzilla · May 23, 2002

Allan,
When you say 455/2 are you simply stating 455 psi in both cylinders? Thanks for the info.

alvanko · May 23, 2002

I have to asume thats what it means . I'm not a deisel mechanic by trade . The service manual shows 455lbs with a small 2 behind it . I have to beleive you are correct . When you check your compression , be sure to use a guage that reads high enough or you'll blow it out . Also the compression is taken while cranking the engine over at 380 (?) RPM's . Do not allow tractor to start while turning it over . I beleive you can unscrew a glow plug and screw in a fitting there to connect to your guage . Let us know what you find !!

dadzilla · May 23, 2002

Thanks Al....I'll give it a try and see what I find.

Slamfire · May 23, 2002

The small 2 behind the 455 lbs, means per square inch. I'll bet.

alvanko · May 23, 2002

I think you are correct . Per square inch . We call it PSI.....pounds per square inch

gatractorman · May 27, 2002

Your probably way ahead of me on this, but the thought that popped to mind was air filter condition.

ekrampitzjr · May 28, 2002

I'm thinking your problem is bad (old) fuel, or maybe the fuel system wasn't completely primed after changing the fuel filter. If the fuel has been in the tractor for more than a year, then it's time for it to go. Diesel fuel gets stale just as gasoline does; it simply takes longer.

Use the highest-cetane diesel fuel you can find. Typically truck stops carry only 40 cetane, though it should be fairly fresh if the truck stop has a lot of business. I use Amoco diesel, which is 47 cetane, the highest rating I can find locally. If it tells you anything, diesel of 50+ cetane is widely used in Europe and 40 cetane would be considered a joke there. Also use a good diesel fuel conditioner. Power Systems, Shell, NAPA, Red Line, and Mr. Moly all work.

Definitely recheck the prime on your system. When I change my fuel filter, which I do annually, I typically have to prime it twice before trying to start it. Don't rip apart the engine until you eliminate the simple fixes.