Bobcat 225G Plus dies when it goes into slow idle?

[Huntxtrm]

Good morning all,
I am new to this forum, glad I found it. Should prove very helpful. I have a Miller Bobcat 225G Plus. Here is the problem. When I start the machine, and let it warm up abit. I switch it to auto idle, and after about 10 seconds the machine tries to idle down. But, it just dies. Like you turned off the switch. It does not even try to stay running. It welds fine on high idle, but it wont ldle down. This all started when some highschool boys, that help out around the property, left the engine switch on. I was out of town at the time, so who knows how long it was on. Days, I'm sure. They were apparently trying to start it, and couldn't, and they left the switch on. I don't know if that had anything to do with it, or not. But, that's when it started. Any ideas? Can you get repair manuals for these? I have the owners manual, but it doesn't say much.

[cruizer]

Handy to know the serial#

[Tryagn5]

lets start at.....

Good morning all,
I am new to this forum, glad I found it. Should prove very helpful. I have a Miller Bobcat 225G Plus. Here is the problem. When I start the machine, and let it warm up abit. I switch it to auto idle, and after about 10 seconds the machine tries to idle down. But, it just dies. Like you turned off the switch. It does not even try to stay running. It welds fine on high idle, but it wont ldle down. This all started when some highschool boys, that help out around the property, left the engine switch on. I was out of town at the time, so who knows how long it was on. Days, I'm sure. They were apparently trying to start it, and couldn't, and they left the switch on. I don't know if that had anything to do with it, or not. But, that's when it started. Any ideas? Can you get repair manuals for these? I have the owners manual, but it doesn't say much.

First check the oil, bettar yet change it, use 10w30 it will use around 2 quarts. Next how old is the fuel? If the fuel is older than a few months, likely the low speed jet in carb is plugged, will have to remove carb and give it a cleaning, while there change the inline fuel filter. If it still is not returning to idle while running at full speed switch the unit to idle and watch the governor arm, as it is about to die check to see if pushing it in the oppsite direction keeps it running, as the governor linkage could be misadjusted. Also i would have an inline spark tester on one of the plugs to varify the switch is not bad killing spark to the engine.
Kevin

[cruizer]

Handy to know which engine is in it, could be something as failed as a spark plug, could be a coil, Oman there is 1 , kohler there are 2. Possibly a vacumn issue, possibly a low oil shutdown, possibly rpm is set too low, and has a combo with some other problem.

Thats why why a serial is handy

[Huntxtrm]

Handy to know which engine is in it, could be something as failed as a spark plug, could be a coil, Oman there is 1 , kohler there are 2. Possibly a vacumn issue, possibly a low oil shutdown, possibly rpm is set too low, and has a combo with some other problem.

Thats why why a serial is handy

KF987260 is the sn
ill change oil and filter tomorrow. But it sounds like the coil shuts down. Doesn't even try to stay runnin. Gas is a little old. Been sitting a couple of months. I'll change the fuel filter too, not a bad idea anyway.

[Huntxtrm]

It is an onan engine. I believe

[Tryagn5]

loss of spark...

It is an onan engine. I believe

I doubt you have a bad coil as it would die on hi or low idle, instead i believe either you have a plugged idle jet on the carb or a bad switch cauing the unit to ground the coil and kill it. So...start the unit leave it on hi idle and manually return the idle solenoid to idle. If it idles fine you know its not the carb but something telling it to shut down..ie the switch...first though check the oil!
Kevin

[Huntxtrm]

Can anybody tell me what oil filter and air filter this machine takes. I don't know if I trust the manual I downloaded. 10w-30 heavy enough? I am in Texas heat. Machine has 320 hours on it. if that helps.

[H80N]

Can anybody tell me what oil filter and air filter this machine takes. I don't know if I trust the manual I downloaded. 10w-30 heavy enough? I am in Texas heat. Machine has 320 hours on it. if that helps.

Why would you not trust the manual..??

according to the serial that you provided... KF987260
this should be your manual

http://www.millerwelds.com/om/o403b_mil.pdf

Oil change, Filter and routine maint info starts on page 19 ( page 27 0f the PDF)

Do not believe that to be the root of your problem...

BUT... do the maintenance... those engines do not live very long if neglected...

THEN... Listen to Cruizer... he knows these machines..

[cruizer]

Yep, its an onan, bad gas is unlikely, more likely is plugged idle jets in the carb, or possibly, too low of oil pressure.

Now regular 10-30 is bad news, so pick a motorcycle oil or diesel oil rated for your temperatures. Reason behind this is these small air cooled engines require Zinc phosphorus for both cooling and pressure purposes. Same as my 140hp Texas chopper. Automotive oil will kill it in short order.

[H80N]

Yep, its an onan, bad gas is unlikely, more likely is plugged idle jets in the carb, or possibly, too low of oil pressure.

Now regular 10-30 is bad news, so pick a motorcycle oil or diesel oil rated for your temperatures. Reason behind this is these small air cooled engines require Zinc phosphorus for both cooling and pressure purposes. Same as my 140hp Texas chopper. Automotive oil will kill it in short order.

My personal preferences over the years have been

For Dino oil: Rotella T

For Synth oil: Mobil-1

But there are a lot of good choices out there...

[Huntxtrm]

Yep, its an onan, bad gas is unlikely, more likely is plugged idle jets in the carb, or possibly, too low of oil pressure. Now regular 10-30 is bad news, so pick a motorcycle oil or diesel oil rated for your temperatures. Reason behind this is these small air cooled engines require Zinc phosphorus for both cooling and pressure purposes. Same as my 140hp Texas chopper. Automotive oil will kill it in short order.

Didn't catch you post in time, I already put in full synthetic 10w-30. Is that bad? Should I drain it and get some delo, like I run in my 7.3? I figured syn was the way to go, for something like this. Guess I should have had some patience.

[Huntxtrm]

I got it running good! The carb was full of some light amber looking jelly? What causes that? I guess that from sitting too long. Or is that from water getting in the carb, somehow? Or, ethanol in the gas? I did change the airfilter, oil filter, oil, fuel filter. Took the carb all the way off and flushed it with carb cleaner and blew out all the holes with air. It was gunky. Gonna change spark plugs now. I bought one, not thinking, so I got to go get another! LOL

[Cgotto6]

Yes. Change the oil again to suggestions above. Glad you got it going. Sounds like the carb was the likely culprit.

[Tryagn5]

I got it running good! The carb was full of some light amber looking jelly? What causes that? I guess that from sitting too long. Or is that from water getting in the carb, somehow? Or, ethanol in the gas? I did change the airfilter, oil filter, oil, fuel filter. Took the carb all the way off and flushed it with carb cleaner and blew out all the holes with air. It was gunky. Gonna change spark plugs now. I bought one, not thinking, so I got to go get another! LOL

ethanol gas strikes again..try to find pure gasoline. Espically if the welder sits for periods of time. With fuel stabil pure gas will last 2-3 years. There is no treatment for ethanol gas which will preserve it past 6 months to a year. Some ethanol gas lasts less than that. Also drain all the old gas out unless you want to clean the carb again.
kevin