QuestionHi John-
Me again. I think I may have found the problem. And it's something you mentioned. I took the carb apart again, but this time more thoroughly, and found some varnished gas partially pluggin the needle valve hole. I never did this before because the carb had previously been "rebuilt" very recently. I guess I shouldn't have trusted that work. Anyway, It ran like a champ for a while and then started bogging down again. So I took the carb apart one more time, and found some more varnished stuff in another orifice. I'm in the process of replacing the filter and gas line now, so I hope that finally does the trick. The only thing that has me baffled is why swapping the carbs initially didn't make this problem go away. Could be a contributing governor problem, which I adjusted, or a near empty fuel tank causing incomplete gas flow as you suggested. Anyway, I think I'm wrapping this one up either way, so many thanks again for your help!
Lance
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Followup To
Question -
John-
Hey. Compression measured 147lbs cold and hot, although it wasn't very hot. Hot enough to get it going and exibit the behavior (about 10 seconds or so, give or take). No I haven't tried this with a full gas tank, but I would think that's a long shot as there's about a foot of gas line between the tank and the carb. I did bypass the fuel filter for a while to see if that was the problem, but no dice. I never took off the governor arm. I only loosened the nut and screw enough to adjust the part that was adjustable (it moves about 10 degrees forward or backward from vertical and is held in place by the screw.
I called Robin today and they're supposed to e-mail me an actual manual for this engine as it's not on their web site. We'll see if it says anything about the governor. The only other thing I can think is to just get a new carb. Thanks again for your suggestions!
Lance
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Followup To
Question -
John-
I'll check the float again, but as I noted I already swapped the carbs and that didn't work. So I was guessing that it wasn't a carb problem, although I'm not totally sure the other carb is without problems.
Lance
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Question -
Hey John. That is really generous of you to look into this a bit! The only numbers are as follows:
MBW Ground Pounder, Slinger, WI 53086
Model R450/1
Robin engine:
EC10D
98ml
2.9/5000 KW/RPM
Fuji Heavy Industries
Carb:
MIC (stamped on one side)
Mikuni Kogyo (stamped on the other side)
That's all there is!
Lance
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Question -
John-
Excellent suggestion, but unfortunately it didn't help. This muffler offers no access internally, so I had to just swap out another used muffler. But that didn't help matters. And there was no significant carbon buildup in the exhaust port.
Any other thoughts/ideas? Could some sort of air/vacuum leak cause this behavior? I think this thing is just possessed. :(
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Question -
Hi. I have a MBW Ground Pounder soil compaction device (sometimes called jumping jacks). It has a 4hp Robin two cycle engine on it. The problem is that when it is at full throttle it will just spontaneously lose power like it's either getting too much gas or not enough. When it's operating normally at full speed I can visually see that even though it should be at full throttle the governor rod and throttle are pulled back so that the throttle is only open about half way. Then, the governor/thottle linkage spontaneously opens full throttle and it bogs down. Then the governor/throttle back off and the engined picks back up. This continues randomly. Unfortunately each time it does this, the lack of engine power causes the machine to lose its pounding cadence and it starts jumping out of control.
I've found that a leaner mixture of gas helps a little. There's only one adjustment screw on the carb and that has no effect. Adjusting the governor setting doesn't seem to help. I swapped carbs from another similar model (same carb) and it didn't help. The only other thing that has helped a bit was to make the governor spring (between the governor arm and the user throttle control a little more taut.
I'm completely baffled here. Could this be some sort of governor problem? Thanks for any advice or suggestions!
Answer -
Hello Lance:
Remove the Muffler and Inspect the Exhaust Port for Carbon Blockage. Check the Muffler and the Spark Arrestor Screen for Blockage. The Spark Arrestor Screen is in the Muffler. If the Exhaust Port or Muffler/Spark Arrestor Screen is Clogged it will Cause the Problem You Described. Hope this Helps. Let me know what Happens, Please. Thanks.
Good Luck
Respectfully
John
Answer -
Hello Lance:
Send me All the Model, Type and Code Numbers Off of the Engine, Please. With these I can View a Breakdown of the Engine and the Carburator and Better Assist you. Thanks.
Respectfully
John
Answer -
Hello Lance:
From the Breakdown, I suggest you Check the Float Level in the Carburator. If the Float Level is too High it Will Flood the Engine of Fuel and If it is too Low it will Starve the Engine of Fuel. Check the Compression. If the Compression is Low it will Cause this Problem Also. You can View a Parts Breakdown and Service Manuals from this Addy http://www.robinamerica.com/manuals/engMans.lasso#. Hope this Helps. Let me know what Happens, Please. Thanks.
Good Luck
Respectfully
John
Answer -
Hello Lance:
Have we Done a Compression Check? Does the Engine Do this With the Gas Tank Full? Did you Remove the Governor Arm from the Shaft at anytime while doing the Carburator? Thanks.
Respectfully
John
Answer -
Hello Lance:
I Suspect the Governor May be Out of Adjustment. Governors are very Critical in Adjustment. Glad your Getting a Manual. Sorry I wasnt of more Help. Let me know what Happens, Please. Thanks.
Very Good Luck
Respectfully
John
Answer Hello Lance:
Varnish that Gas Forms Inside the Carburators of Small Engines give all the Small Engine Mechanics a Headache. It is Hard to Remove and If Not Completely Removed it will Do as it Did with you. It will Flake Off and Continue to Cause Problems. Im Glad we Made Progress on this. Always Remember Us at All Experts. May the All Mighty Bless You and Yours. May All your Mechanical Problems be SMALL ONES. Thanks for the Email.
Very Good Luck
Respectfully
John
