Bobcat Welding Machine

Date 06-07-2011 16:29

Could be carb linkage, that's an easy check but there's a lot going on inside one of those welders, more than I can help with. Im sure a more knowledgeable person will respond though.

By TimGary (****)

Date 06-07-2011 18:10

I believe there is a multi position run switch that either keeps the engine running full bore constantly (for when you are doing a lot of heavy continuous welding) or allows the engine to idle down inbetween welds (for when you are welding intermitently).
Which switch position did you use?

Tim

By Johnny Walker (***)

Date 06-08-2011 01:28

Oil pressure sending unit beside oil filter check the two wires

By Milton Gravitt (***)

Date 06-08-2011 12:19

The switch that idles down when you not running continuous.

M.G.

By Regmanager (**)

Date 06-08-2011 19:05 Edited 06-08-2011 19:08

You're not giving enough information. Doesn't idle down like it use to? Does it die? Is it stumbling? Does it cycle up and down? Does it not idle at all? 99 model. How long have you let it sit? How old is the gas? If I was to hazard a guess with 66 hours on it which is 5 hours a year, you will be buying a new carburator as your low speed jets are completely gunked up from old gas. No way to clean those and its a throw away carb. I'll say 99% sure on this.

Call me at 903-838-3023 7 am cst-3pm cst and I'll walk you through it.

Ask for Joe
Regional Service Manager

By Tommyjoking (****)

Date 06-08-2011 20:21

Joe Not to disagree with most of what you have said but....on the low speed jets and passages at least on the "Onan twins" I have been able to restore them to working condition without too much effort. The right solvents and a good supply of compressed air + some needles and they can be cleaned....tedious sometimes but doable. Not really any different then a lot of 4 stroke motorcycle carbs as far as the cleaning of them go. It is good of you to offer your time and expertise to Milton, he is a good guy and I appreciate that

Milton run it on high idle and check the solenoid at the back over the cylinders and make sure it is kicking in...on run/idle It should let go after 20 secs or so of run time. Sometimes they get stuck make sure it moves freely and kicks in on RUN switch.   Check to make sure all the springs on the carb linkage and the rod running at a 90 degree angle from your solenoid all look right (this rod has a wing nut on it for adjustment with a long spring..it is connected to a rod that runs into the case).   If all that looks ok chances are it is exactly what Joe said...your carb is gummed up....it does not make sense that it is out of adjustment with so little use. It is not a difficult job just takes a little patience.

BEFORE you remove the carb, drain the float bowl on the carb (it will have a screw for doing such) then siphon all the gas out of tank, replace the fuel filter with a new one and add some fresh gas (not gas sitting in a can in the shop..NEW GAS).   Give that a try, you might get lucky and drain out a big piece of dirt or have a clogged filter making it starve for fuel and run erratic.

IF it is an ONAN chances are the carb assembly is held on by bolts under the intake manifold...your will have to unbolt the intake manifold to get the carb off....if you are carefull you can reuse those intake manifold gaskets.   If it is a Kohler, well you just have to figure out how to get it apart....USE a paint pen or something similar to mark the positions/adjustment of your linkages...a camera and ziploc bags are your friend when dissembling things your unfamiliar with. Your best bet is to remove the carb, remove the float bowl, float, float valve, remove the main jet and make sure it is open and clean (torch tip files or sewing needles), you will see small jets and passages in the float bowl-they must be open and clean, note where the passages blow out of in the carb throat...you can check them with compressed air and a gun with a rubber tip.   Regular spray carb cleaner and some rubber gloves and goggles is ok....going to NAPA and getting a gallon of Berrymans CHEM DIP is better (BAD BAD STUFF USE PPE AND BE CAREFULL). Especially if you use the chem dip....remove all gaskets and rubber from the carb body and soak it in the chem dip for at least 24 hours, wash with soap and water or spray carb cleaner after it is done..Whatever the chem dip touches you should be prepared to throw away (except for the carb LOL).   DO NOT LET THAT STUFF TOUCH YOUR SKIN, it will not burn you it is just bad and the smell takes weeks to wear off. Blow it out again, make sure all passages are clear and then reassemble. IF you did not do it first thing make sure you replaced the fuel filter and got fresh gas before you try to start it!!!   I would bet a six pack of good German beer that will get you going if you do it right.   I reckon if you do not want to tackle it a good LWS would charge you about five hours labor to do the same thing...a good small engine shop could do it easily.

I have to agree with Joe ...it is 98% chance you have a plugged up carb from old fuel and lack of use. BTW if your going to fix it you need to go ahead and replace the oil filter and oil with fresh. Oil sours from fuel/exhaust vapors with little use...if it just sits around.

Good luck Mr. Gravitt
Best regards
Tommy

By Milton Gravitt (***)

Date 06-08-2011 22:39

Thanks Tommy, I found my manual and it said on idle it is to idle at 2200 rpm and when you kick it up on fast it should run at 3700 rpm. You would think it was going to go dead on idle ,but now it might be idling right now.I will check it out this weekend a little further.
How do you like working for yourself, do you miss working in the air conditioning, because when you work in the aerospace industry it was air conditioning wasn't. It has being hot here when I get home I don"t like to get outside.

M.G.
It is an Onan Motor.Tommy if I drink a six pack of good German beer I wouldn't get anything done.LOL

By Tommyjoking (****)

Date 06-08-2011 23:51

Yea Milton it is hot as Hades here...I only miss the A/C and my little tig table when I am not making money.....other then that screw it!!! I can handle the Sun and the Dirt. My wife is suffering heat exhaustion right now, I was getting cold chills out on an install last week in the Sun, I had drank about 12 12 oz bottles of water that day.

Idle is pretty high on those little motors Milton, if it sounds like it is coughing and about to die I can tell you without much question it is a stuffed up carb or a lack of fuel supply. Do those checks I outlined first, but i can just about guarantee you will be cleaning that carb out in the end. It is practically a brand new machine so it is well worth the effort to clean her up and make it run right. I will pm you my phone number if you need any help on it.

Take care
TOmmy

By Pickupman (***)

Date 06-08-2011 23:55

I have a Trailblazer with an Onan in it. It gets regular use but still runs crappy from time to time. Asked the guy who works on it for us and he recommended dumping a whole can of Sea Foam in the tank once in a while. The stuff they sell for "Gas" these days will barely burn if you put a match to it. The Sea Foam really helps. You might try it to.

By DaveBoyer (*****)

Date 06-09-2011 02:05

Once You get it cleaned out and working properly... Use a fuel stabilizer, don't keep a full tank, as You won't use it up before all the good stuff evaporates, and run the engine frequently.

I have a Ranger 9 that I keep mostly for standby power for the house, and I run it every month to keep the battery charged and the carb working. I use fuel stabilizer and carb cleaner in the gas to chase away the evil spirits.

By Milton Gravitt (***)

Date 06-09-2011 12:42

Thanks you all for your advice and help.
M.G.

By Regmanager (**)

Date 06-10-2011 14:28

Good advice from all. Welding machines are made to run. They should have at least 100 hrs a year. All newer models, no matter what engine have anti back fire solenoids directly on the carb. Touchy little things when it comes to bad gas. I was assuming his 99 was a kohler as Onan was in transition with Robin in 98. Removing that carb and replacing it is easy as pie compared to the onan. Just the carb bolts and linkage. No bolts under the manifold to fool with. We had an ice storm here in 2000 which knocked out power for weeks. We sold 1000 in that time. I've replaced solenoids and carbs on 600 of them. The problem with the kohler is you can clean the jets but the varnish never disappears. So much less hassle to just toss the carb and start fresh.