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Curtis B.
Curtis B., Technician
Category: Construction and Road Equipment
Satisfied Customers: 26032
Experience:  Technican turned service manager with multiple lines of equipment and rental units.
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5/22/15 I have a Bobcat M 610 with a Wisconsin engine. When

Customer Question

5/22/15
Hello
I have a Bobcat M 610 with a Wisconsin engine.
When I start the engine, it will start and run at low rpm. When the throttle is moved to run at higher rpm it stalls, if throttle is
moved quickly back to lower rpm position, it recovers and continues to run. If throttle is left at high rpm it stalls and dies. I
installed a new gas filter and new fuel pump.
The machine is able to be driven and bucket is moveable at low rpm, but as soon as the rpm is increased the engine dies.
Usually the engine will restart.
Can you help?
Thanks, Duke
Submitted: 1 year ago.
Category: Construction and Road Equipment
Customer: replied 1 year ago.
I noticed pressure buildup in the gas tank
Expert:  Curtis B. replied 1 year ago.
With the VH4D, have you checked for spark on all cylinders? I suspect you have engine that may be only running on two cylinders! Loosen the spark plug wires and with engine idling, pull off one wire at a time and check for spark. Then pull both wires on one bank, to see if engine continues to run. If engine dies when both wires are removed, the opposite side is not firing.
Customer: replied 1 year ago.
I loosened the spark plug wires and with engine idling, pulled off one wire at a time and check for spark. Then pulled both
wires on one bank, to see if engine continues to run. Engine continued to run.
Expert:  Curtis B. replied 1 year ago.
Distributor or magneto? Have you replaced the points and condenser in the distributor? Have you tried moving the timing?
Customer: replied 1 year ago.
The points and condenser in the distributor are ok, also installed new plugs
Expert:  Curtis B. replied 1 year ago.
Point gap correct? Have you tired to turn the distributor to change the timing? Have you checked the manifold vacuum with gage, to see if the vacuum falls off to near zero on throttle up? This would show if the exhaust is plugged.
Customer: replied 1 year ago.
The engine had a tuneup by a mechanic. I have no means at this time, to check the manifold vacuum with a gage. The muffler is
accessible and the exhaust is steady
Expert:  Curtis B. replied 1 year ago.
Engine not throttling up can be many things, but the points setting is one that needs to be right! And the timing needs to be set. Did it run right after you got the (tuneup)?
Customer: replied 1 year ago.
Yes
Expert:  Curtis B. replied 1 year ago.
Have YOU checked the points?
Customer: replied 1 year ago.
No, but I will. I'll have to do it tomorrow.
Expert:  Curtis B. replied 1 year ago.
OK, points on 4 cylinder needs to be .020 to .025 inch.
Customer: replied 1 year ago.
I will check the points. I believe they are properly set, what are the next things to do while I'm at the engine
Expert:  Curtis B. replied 1 year ago.
See if the carburetor has good fuel flow to it, when cranking.
Customer: replied 1 year ago.
I will check if the carburetor has good fuel flow to it, when cranking as you suggest, when I changed the fuel pump I checked
the flow at that time, but I will check it again. What else?
Expert:  Curtis B. replied 1 year ago.
Next I would try turning the distributor to change the timing.
Customer: replied 1 year ago.
I am uncomfortable messing with the timing on an engine that starts with no problems.
Expert:  Curtis B. replied 1 year ago.
OK, I can under stand that. But all you have to do is mark where it is, so you can return it to the exact same place if needed. Let me know what you find. Thanks.
Customer: replied 1 year ago.
What do you want me to change it to?
Expert:  Curtis B. replied 1 year ago.
I always just move it as engine is running , a little bit at a time, to see if it runs better or worse, if worse, I go back the other direction! I set it where it runs the best, ***** ***** down the distributor.
Customer: replied 1 year ago.
Are you saying move the distributor a bit tighten it down then drive it to see how it runs, or runs at an idle?
Expert:  Curtis B. replied 1 year ago.
I would just do it at idle, and then check it, just loosen the distributor so it can be moved, not fully loose! Then if it seems to run better, then run your test!
Customer: replied 1 year ago.
The engine runs great at an idle right now, the problem is running at a high rpm or full throttle
Expert:  Curtis B. replied 1 year ago.
You have to make some changes , unless you are satisfied with idle. I can only make suggestions that I feel will help. Something has changed since you had it tuned up!
Customer: replied 1 year ago.
I agree something has changed since it was tuned up, and I am happy to make changes, but in your last suggestion your asking me to adjust the distributor to attain a good running engine at idle, that is already running good at idle. Again the problem is the engine does not run at a high rpm or full throttle. I understand you know more about mechanics than I do, so I will do as you suggest because maybe I am missing something.
Expert:  Curtis B. replied 1 year ago.
OK, let me know. I will be here.

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