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Wisconsin Engines

Bobcat VH4D vapor lock?


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  #1  
Old 07-21-2008, 09:40 PM
retmsg retmsg is offline
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Question Bobcat VH4D vapor lock?

Help my bobcat 610 runs great for about 10 min then she falls on her nose, The only way to keep it going is to choke it. I have replaced the fuel lines from 1/4 to 3/8 and insulated the fuel lines. I have converted the fuel pump from mech to electric and have a consent supply of fuel. She ran great all winter and did not have this problem untill I started to work it in the heat, Any ideas ???
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Old 07-21-2008, 11:11 PM
Ed Radtke Ed Radtke is offline
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Default Re: VH4D vapor lock?

If the engine is non original to this machine,then look at the intake,exhaust manifold to see if they are cast as one piece.if they are then use a saw to separate them.When you look at them you will see where to cut.This is the factory recommendation to solve carb boiling problems.There is no need to remove them for this.Also be sure the fuel tank vent is open.
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Old 07-22-2008, 08:24 AM
K D Redd K D Redd is offline
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Default Re: VH4D vapor lock?

Have you looked at your ignition system also? Sometime an ignition problem can mask itself as a fuel system problem even do to pulling the choke will keep the rnginr running.

Kent
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Old 07-22-2008, 09:39 AM
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Elden DuRand Elden DuRand is offline
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Default Re: VH4D vapor lock?

Also check to make sure the gas tank vent is not clogged.

Take care - Elden
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Old 07-22-2008, 06:25 PM
Zira Zira is offline
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Default Re: Bobcat VH4D vapor lock?

If this is a coil/distributer ignition, try replacing the coil.
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Old 07-22-2008, 07:32 PM
JHFoster JHFoster is offline
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Default Re: Bobcat VH4D vapor lock?

These points/condenser are harder to change then the old fords tractors with the dist. in front of the engine. The last time I changed mine in my bobcat I pulled the motor.
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Old 07-23-2008, 08:16 PM
retmsg retmsg is offline
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Default Re: VH4D vapor lock?

Quote:
Originally Posted by Ed Radtke View Post
If the engine is non original to this machine,then look at the intake,exhaust manifold to see if they are cast as one piece.if they are then use a saw to separate them.When you look at them you will see where to cut.This is the factory recommendation to solve carb boiling problems.There is no need to remove them for this.Also be sure the fuel tank vent is open.
Thanks for your input on seperating the manifolds I thought it was a poor design. I think that this engine is OEM, I have refilled my FUEL tank and feel I have gotten some poor fuel as I ran it hard for 1hr @ 90 deg with no problems. Is the manifold modification only on bobcat applications ??.
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Old 07-23-2008, 08:22 PM
retmsg retmsg is offline
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Default Re: Bobcat VH4D vapor lock?

Quote:
Originally Posted by JHFoster View Post
These points/condenser are harder to change then the old fords tractors with the dist. in front of the engine. The last time I changed mine in my bobcat I pulled the motor.
My dist is in the back of the bobcat and easy access when I open the door
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Old 07-25-2008, 09:39 PM
Ed Radtke Ed Radtke is offline
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Default Re: Bobcat VH4D vapor lock?

The modification applied to any application that developed the problem.
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Old 07-04-2009, 03:58 PM
JameySmith JameySmith is offline
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Default Re: Bobcat VH4D vapor lock?

I had the same problem with my melroe 610 and the oil seal on the distributor was bad so the engine was pumping oil up into the points causing poor ignition
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Old 05-10-2010, 03:47 PM
brwracing brwracing is offline
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Default Re: Bobcat VH4D vapor lock?

I have a bobcat 720 with a tired vf4d 30 horse engine.

Is it worth keeping this old engine running?
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Old 05-10-2010, 04:57 PM
Dempster Dempster is offline
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Default Re: Bobcat VH4D vapor lock?

You'll spend as much either way fixing the engine you have or trying to convert it with a small diesel like used in the newer ones today.
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Old 05-10-2010, 05:10 PM
Dempster Dempster is offline
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Arrow Re: Bobcat VH4D vapor lock?

This illustration from a Wisconsin VG4D manual shows where to make hack saw cuts on a manifold on a engine that will be ran mostly in hot weather and suffers from hard starting in hot weather.
Attached Thumbnails
Wisc VG4 Manifold Cuts 002.jpg   Wisc VG4 Manifold Cuts 2.jpg  
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