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lincoln ranger 9 problems

phantom71

Hot Rolled
Joined
Mar 13, 2009
Location
Alabama, U.S.A
Hello everyone, I normally post on the SB forum but this is a subject more suited here. The portable welder at my work has quit and was wondering if ya'll might be able to help figure out what's going on. It's a ten year old ranger 9 w/ the onan 18 aircooled engine, while in use last friday a plastic bag from lowes got sucked up to the back of the motor. Yes, it ran hot and shut down, after cooling off and changing oil it will not crank. It will not fire the plugs, we've changed the coil and condenser still wont work. While the motor is turning there is no spark but when you release the start button about three seconds later the large output relay clicks and a faint orange spark goes through the plug. Any suggestions? we don't have a technical manual for this machine, is there a shut down switch that could be stuck? or could it have gotten hot enough to screw up the module? thanks for any help, phantom71.
 
Phantom:

My first suggestion to you is to take off the sheet metal cover on the welding generator & look on the inside of it. Lincoln used to paste a printed wiring diagram inside the generator cover.

If this diagram is not in place, call Lincoln Electric's tech support in Cleveland, OH. They are quite good about getting a copy of the manual to you, usually at no charge. I was in a jam with my own Lncoln engine driven welder ( an old "Weldanpower"), and they emailed me the wiring diagram as a PDF file, then followed up with a copy of the manual in the mail.

If you go to the Lincoln website and have the "code" on the machine, you may also be able to download a complete manual including wiring diagram.

Setting aside the lack of a manual, and admtting to no specific experience with an Onan engine or your machine:

The machine experienced an overheated engine. Afterwards, you note the machne wil "not crank". However, from reading your email, it sounds like the starter motor turns over the engine OK. My first guess is that one of the safeguards on the engine is keepng the ignition from firing during the start cycle. The engine may have a low oil pressure switch to shut down the engine in the event of a loss of oil pressure. Not sure about a high oil temp switch. I'd locate these two switches and check continuity accorss them with a multimeter.

I would also suggest you remove the low oil pressure switch from the tapping in the engine and screw in a mechanical pressure gauge with a good low-range scale (0-50 psi is plenty). Next, I do not know if your engine has electronic ignition vs. coil-&-points. Being only 9 yrs old, I am inclined to believe it has electronic igntion. For that reason, you should NOT try cranking the engine with the plug leads simply disconnected from the sparkplugs, or plugs hanging loosely on the plug wires, ungrounded. You need to either ground out the plug wires (if disconnected from the sparkplugs) or make sure to temporarily disconnect current to the ignition circuit before test-crankign the engine. With the gauge in place in the engine block, crank the engine. Note how much pressure builds and how long it takes to happen. I am unsure what the setpoint on a low oil pressure switch is, but I am guessing it is fairly low, like maybe 5 psi. See what oil pressure the engine builds cold while cranking.
Also test the low oil pressure switch on shop air to see if it opens when pressure is applied to it and recloses when pressure is bled off.

Not to cast doom and gloom, but as a worst-case scenario: the engine overheated and this may well have thinned the oil sufficiently to cause damage to the engine bearings with resulting low oil pressure. The damage was severe neough to keep from building oil pressure on cranking. I tend to think this is unlikely, since you mention changing the oil after the overheat incident. New oil cold, should be thick enough to allow the system to build a little oil pressure on cranking, even on a badly worn engine.

Or, the resulting overheat situation tripped a high temperature switch (if one is on this engine). This switch may not have reset.

These two safeguard switches are likely wired in series with the primary current to the ignition coil. It remains to be seen if they are preventing power from getting to the coil during starting.

My next guess is there is some kind of "start mode" vs. "run mode" on the engine control circuits. In the "start mode", the low oil pressure shutdown switch is bypassed to allow the engine to have spark while cranking up from 0 oil pressure. The start mode may use a relay to bypass the low oil pressure switch while the ignition switch is toggled to the "start" position. This same relay may also feed full battery voltage to the ignition coil(s) during starting. Normally, ignition coils are supplied with something less than 12 volts to the primary side. The 12 volts are lowered to about half that using a "ballast resistor". Some ignition coils have this resistor built into them, and some systems rely on external resistors. On older cars and some industrial engines, there was wiring in the starting circuit to bypass these resistors and put full battery voltage into the coils. The idea was the heavy current draw of the starting motor was going to pull down battery voltage, and a very weak spark would result. So, during starting, full battery voltage was supplied to the coil. Once the engine "caught", the ignition system was switched from "start mode" to "run mode". This would put the low oil pressure switch and the ballast resistors in series with the ignition coils. Any current going to the coils had to pass thru the safety shutdown switches.

I would start by NOT cranking the engine, put the igntion to the "run" position, and check voltage to the primary side of the coils. If current is getting to the coils, then the matter is a weak spark. If current is not getting to the coils, then the start checking continuity thru the wiring and components in the wiring on the primary side of the coils.

Once I had verified what was going on in the primary side wiring in the "run" position, I would repeat this in the "Start" mode. THis will mean crankign the engine. If no power is getting to the coils during cranking or "start mode", then I'd go back to the idea that one of the safeguards is keeping current from getting to the coils.

You mention a relay as clicking and some time delay, then seeing a weak yellowish spark. It is possible that Lincoln used some sort of time delay circuit (either a time delay relay or a solid state cricuit). This would automatically hold out the oil pressure shutdown (and any other shutdowns) to allow time for the engine to start and build oil pressure. It is possible this time delay circuit is not functioning as it should, not bypassing the low oil pressure shutdown switch. As soon as you let off the swtich when cranking the engine, there is no spark since the low oil pressure switch may be keping current from getting to the coil. After a time, the time delay relay (or timing circuit) runs out, and switches things to the "run mode". This is when you start seeing spark.

If the spark is weak, that is a whole 'nother story. I think you mentined putting new coils on the machine. Check them against the old coils to see if the new coils ahve internal resistance (the old coils may have used an external resistance). If the new coils have the internal resistance vs. external on the old, then lower primary voltage may be cuasing a weka spark. The overheating could have fried the plug wires, and then there is the condition of the cap and rotor. Condensers break down with age as well (if this system still uses them).

These are generalized guesses on my part. I ride old Airhead BMW motorcycles. These have air cooled "boxer" engines like the Onan, but that is where the similarities end. The Airhead engines still use the old coil and points ignition, with one set of points, one condenser and two coils. Not sure if the Onan engine has gone to electronic ignition since it is much newer than my Airhead bike engines ( 30 years old).


There is another method of checking to see where the problem lies. I can;t say I recommend it, but it is what some mechanics would do. That is to run a hot wire or jumper from the battery to the primary side of the coils, and try cranking the engine. If the engine starts and runs, then you know one of two things is going on:
-somethng was cutting out the current to the coils during the start cycle with normal wiring in place
-or, the spark during the starting cycle is too weak.

I would not try hot wiring until you have confirmed the engine has good oil pressure during cranking.

I tend to believe that with a multimeter, an oil pressure gauge, and some patience you should find the problem.

Joe Michaels
 
Onan

I had a Onan engine on a generator with a bad ignition coil, It was a double coil with both plug wires comeing out the top, no distributor. Onan wanted over $250.00 for the coil;
ten years ago. Not wanting to wait two weeks to get the part, I made a bracket to hold
two 12v coils[automotive] and wired them paralell, they both fired at the same time, but one into an empty cylinder. Worked so well, I never did order the correct coil. [acme thread]
 
Acme Thread:

What you accomplished was to re-invent the ignition used on the older BMW boxer type motorcycle engines. These used two ordinary ignition coils, one set of points, one condenser, no distributor. Both cylinders fired at the same time, but were 180 degrees out. So, one cylinder fired a little before TDC compression, and the other fired a little before TDC on the exhaust stroke. It was quite commonly done on 2 cylinder motorcycle engines aside from the BMW's. The Onan is a "boxer" type engine, so this scheme was probably what they uaccomplished with the original "double coil".

BMW bikes did not use any kind of resistance to drop voltage supplied to the coils. The primary terminals of the coils are connected in series.

Joe Michaels
 
Thanks joe, that is a good bit of info. I was able to find a pdf file on the engine last night, it gives many of the same tips as you. Did'nt even cross my mind to go directly to lincoln:o, we're going to work on it tomorrow so between your response and the file I think we'll get it going. It is electronic ignition with a condenser hooked to the coil, the oil pressure switch checks out fine and it seems to be pumping plenty of oil. When it ran hot there was no unusual noises ie; rattles, knocks, or squeals it just cut off like someone flipped the kill switch. I'm beginning to think the ignition module under the flywheel failed under the heat stress. I'm gonna check out the lincoln site and see if I can find anything there, thanks again joe and to all who responded. Cheers, phantom71
 
Hi I'm new here and I'm looking for some help. My intent is genuine. I mean no disrespect and hope by asking, I,intern , am not stepping on any toes. I'm a retired veteran USMC to all my brothers Sempher Fi and thanks for your service. So with all this time on my hands and to (sort of speak) keep out of trouble(LOL) Custum building is my stong point. Harley's ,welder's , and generators are my specialties. So this is my problem : got a miller bobcat welder . And you know how it's got a run and a run/idle . Is there a way i can bypass that option and put a switch on it ? My objective is to run it manually from the switch to the stinger. I've done this before to an older model Lincoln . Anyway. on the Miller , when I start it up it doesn't do anything. The control solenoid pulls the governor lever back and holds it at low idle but when i strike an arc -nothing. It stays at the RPM's it's at . It doesn't go up to the high RPM's like it's supposed to . I read somewhere, on a Miller, you can bypass grounding J pin and put a switch between A and B pins. Can anyone explain this procedure in terms this retired dummy can understand? Maybe even a rough drawing would help. Thanks . I appreciate any input or suggestions. 121pete
 
Hi I'm new here and I'm looking for some help. My intent is genuine. I mean no disrespect and hope by asking, I,intern , am not stepping on any toes. I'm a retired veteran USMC to all my brothers Sempher Fi and thanks for your service. So with all this time on my hands and to (sort of speak) keep out of trouble(LOL) Custum building is my stong point. Harley's ,welder's , and generators are my specialties. So this is my problem : got a miller bobcat welder . And you know how it's got a run and a run/idle . Is there a way i can bypass that option and put a switch on it ? My objective is to run it manually from the switch to the stinger. I've done this before to an older model Lincoln . Anyway. on the Miller , when I start it up it doesn't do anything. The control solenoid pulls the governor lever back and holds it at low idle but when i strike an arc -nothing. It stays at the RPM's it's at . It doesn't go up to the high RPM's like it's supposed to . I read somewhere, on a Miller, you can bypass grounding J pin and put a switch between A and B pins. Can anyone explain this procedure in terms this retired dummy can understand? Maybe even a rough drawing would help. Thanks . I appreciate any input or suggestions. 121pete
I would go over to the Miller welds forum and post this question, duane 55 or cruiser might have an answer for you.
 








 
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