VH4D QUESTION

Hi all,

Hope everyone had a nice Christmas. I had a friend who is pretty good with old motors come by to take a look at my VH4D skid loader and the carb spitting issue I have been having, he spent a good 3 hours reading the manual and checking different things and this I know for sure, the timing is correct, the valves both intake and exhaust are working fine, compression is good. what we did find was the carb has 2 almost "ALLTHREAD" type bolts thread on both sides that screw into the top of the carb, then the carb sort of slides under the exhaust manifold, the bolts stick up thru the manifold and simply washer and nut tighten. Problem is we noticed the one bolt doesn"t tighten the threads inside the carb body are stripped out and I cant just get a nut and bolt because the air/fuel adjustment screw is directly in the way so I will need to try and tap and get a slightly larger screw. Question- could this seal breach between the carb and exhaust manifold cause the spitting problem I have been having? thanks all
 
Yes I guess? as you know im not too well versed in this stuff but learning more and more everyday. I guess it would be a vac leak, when I cover the carb with the palm of my hand it sucks it in pretty good? so I guess since the carb attaches to the exhaust manifold the proper terminology would be intake manifold. so if that carb to intake manifold is leaking would that cause it to spit? SCOTT
 
Scott,

I am currently rebuilding this same engine for my Bobcat M-600. You say the valves are good, did you check the valve lash? If so, what is it?

What is the compression? Did you do a leakdown test? A leakdown test may indicate a leaking intake valve.

This to me sounds like a valve issue, but possibly an ignition issue too. You may benefit from new points, condensor, and cap. How long since an ignition tune up?

Does it run better/good with the choke partially, or fully engaged? If so, this would point to a dirty carb.

Regards,
Tim in Mass
 
Yes but should smooth out with use of choke you may have more than one problem.I am just guessing without being there!
 
Yes, vacuum leaks can cause lean backfire through the carb, usually when coming off idle, trying to bring RPM up.

If over sizing the stripped bolt hole is going to be difficult, might be a good place for a Heli-Coil.
 
Thanks to all for the advice however, I righty tightied a little too much and cracked the carb base so had to find one which I did and now just waiting for it to come in. Scott
 

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