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jdemaris
05-01-2004 05:37:08
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Re: gas tractor and ether in reply to Farmer in the Dells (WI), 05-01-2004 04:50:33
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I haven't seen the kind of damage occur in gas engines that frequently appears in diesels after heavy ether use. Diesels have a much higher compression ratio - usually around 22 -1, whereas gas engines in farm tractors are usually very low, in the 6 or 7 - 1 range. So the internal high pressures caused by ether exploding are higher in the diesels. Of course, there are variables, and some tractors have relatively high compression in their gas engines, e.g. Olivers, or John Deeres with high-altitude pistons. I also have to point out that I don't see much ether use with gas engines, so it's hard to compare. I've been working on this stuff for over 40 years, including time at several Deere industrial/ag/forestry dealerships. We expected starting problems in cold weather with diesels, it's inherent in the design. But, if a gas engine failed to start - it indicated a problem to be fixed - unless we're talking about -30F temperatures. If a gas engine has good spark, and a properly working fuel system, it has to be REAL low on compression not to start. If an engine is that beat, it will also use oil, have blowby, and foul spark plugs. Compression tests can be misleading when attempting to identify starting problems. Also keep in mind, that not only does the gas engine require compression on one of the "up" strokes of the "Otto" cycle, it must also have ample negative-pressure on one of the down-strokes to draw in the air-fuel mixture unless it has fuel-injection (I haven't seen any fuel-injected gas tractors - but who knows?). So, a weak engine with air leaks in the intake, or a choke plate that doesn't close all the way, or a low float level, and also cause starting problems. A diesel engine relies on compression to create sufficient heat for combustion. A gas engine does not. So, if you have a gas engine that needs ether to start, you either have very low compression - or something amiss in the fuel system. Again, something as simple as a non-functioning choke or an air leak in the intake could cause such a problem. Maybe I didn't answer your question? Truth is, if I parked a gas powered tractor that was running okay, and the next day it wouldn't start - ether wouldn't even be a consideration. I'd try to diagnose the problem, and wouldn't expect using ether to make much of a difference.
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