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**Predator 212 Hemi Valve Lash Question, Uncontrolled RPM Please Help**

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BHall3

New member
I have a two part question for you guys. 1.) I've adjusted both the exhaust AND intake valve lash at .003" per a lot of videos I've watched while the engine was at top dead center on the non-compression stroke. Now when I try to start it, the tension on the pull rope is so hard it makes it almost impossible to start. What did I do wrong or what is the correct lash for both exhaust and intake? 2.) I'm still struggling with the high uncontrollable RPMs once the engine is started. I posted another thread about this but I couldn't get a clear answer. The engine at idle revs up by itself with no input from the throttle butterfly, after awhile of idling it revs super high to the point I have to shut the engine off to prevent damage or injury. Also, while its running, if I open the choke it acts like I open the throttle all the way (which I'm not touching the throttle at all and it is completely closed) and revs extremely high. Would this be due to incorrect valve lash? I've checked for leaks on the carb, the black idle screw is all the way out, carb is super clean.

Modifications I've done: ARC Speedway Billet Flywheel with 32° advanced timing, complete governor removal (sealed hole with correct bolt with red Loctite), removed oil level float/sensor (sealed hole with correct bolt with red Loctite), header pipe, Airspeed II intake adapter with filter, 18 pound WMS racer valve springs and a WMS side throttle plate that mounts to the flywheel cover.

Any and all help is much appreciated! Thanks in advance. I'm willing to give out my personal phone number and email if need be for faster communication and to send pictures or videos of the engine and what it is doing.
 
first the lash needs to be set on the compression stroke.
bring it up too compression then using a Philips screw driver find tdc set it there . its important that its at tdc or just slightly past like one quarter inch no more.
lash setting at .003 could be okay .0015 may help .
too loose the compression release wont work.
too tight it wont start.
the revving issues ; someone asked about a throttle return spring do ypu have one?
have you had the carb off for any reason and if so what did you do ?
take the throttle kit off and tie the butterfly back will it do the same thing ?
when you look in the carb is the butterfly closed ?
 
Flattop1 thank you for your reply,

Compression stroke meaning, when I stick my thumb over the spark plug hole, I should feel the compression trying to suck my thumb in the hole correct? And then once the piston is at the top of that stroke adjust the lash?

I do not have a throttle return spring on the engine, the WMS throttle kit has a heavy duty spring on the "flap" that keeps the throttle rod pushed back at all times, meaning the butterfly is always kept closed until that "flap" is pulled forward (by throttle cable or by hand) towards the front of the kart. If I knew how to paste/post pictures in here I would show you but all I can do is send a link to the WMS throttle kit. https://www.ebay.com/itm/Throttle-L...or-212cc-OHV-Engine-and-Similar-/123433545425 Do I need to attach a throttle return spring to it even though the butterfly is staying closed the whole time?

Yes, I have taken the carb off several times for cleaning and such, just took it completely apart cleaned everything and put the new jet in awhile ago (forgot to mention the jet in the mods in my initial post, .36 I believe) I'll have to take it off and see if the butterfly is closed when the carb is off of the block, I have not checked that yet as well as tying the butterfly back.
 
No when it wants to push out . both valves should be closed.
That return spring should be sufficent.
I suspect an air leak .
Two things.
First are you sure the air filter adapter gaskets are correct as they can be upside down . 2 gaskets on the plastic insulator one on each side .
Second get you a spray bottle full of water.
A second person would help here. Be sure its clamped or bolted down .
Start it and try to control speed by chokeing it with your hand on off on off.
Spray around the carb with the water it should stop or stutter at the leak.
Actually from what you describe the leak or broken insulator should be visible.
 
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Problem solved, I'm an idiot, that WMS throttle plate holds the throttle butterfly back (towards) the back of the motor which is wide open on the carb, and then when you pull the throttle cable or manually pull the throttle linkage towards the front of the motor, it closes the butterfly. So it was completely backwards essentially and I didn't event think twice about it. So when you "hit the gas" it actually closes the butterfly instead of opening it which explains the very high RPM once you start it. I adjusted the valve lash just as you said and it makes a lot more sense now. I hope someone else can learn from my mistake and I'll call it stupidity! Thank you flattop1 for all of your help and suggestions, it is much appreciated!
 
Quick question I am having the same problem. I did some valve work and I reset the clearances on both to .003 but it feels a little to right when I try and pull start it what should I do. Thanks.
 
Cas68 said:
Quick question I am having the same problem. I did some valve work and I reset the clearances on both to .003 but it feels a little to right when I try and pull start it what should I do. Thanks.
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Reset the lash , be very careful to be right at tdc on compression.
Watch the valves and especially the exhaust so it's not on the compression release . It will open and close very quickly a slight amount .
Try to get them at .0015-2 .
 
It is at top dead center and the moment I move the shaft a little the exhaust starts opening is that what you are talking about?
 
Yes move it a little more till it shuts .
The are two tdc cycles , one is the compression stroke, one is the overlap . You want compression .
You may know this , its easily confused .
 
Alright because it just seems odd to me that immediately after the intake closes the exhaust starts opening. So I should move it backwards so that the exhaust valve isn't being opened at all?
 
I am also seeing a lot of people talk about the compression release and was wondering if maybe my lash is ok just I need to pull it when the compression isn't high?
 
The exhaust compression release is a quick open close .
Use a pencil in the plug hole to feel the piston movement.
Just start over it's a bit trickey , try to roll it at the clutch the rope moves things too fast .
 
Cas68 said:
Quick question I am having the same problem. I did some valve work and I reset the clearances on both to .003 but it feels a little to right when I try and pull start it what should I do. Thanks.
Click to expand...
Did you get it figured out ? Cas68
 
Cas68 said:
Alright because it just seems odd to me that immediately after the intake closes the exhaust starts opening. So I should move it backwards so that the exhaust valve isn't being opened at all?
Click to expand...
That sounds like overlap to me if you're at TDC. Or am I missing something.
 
The Intake valve valve closes Lets say 42* ABDC the piston travels to TDC on the compression stroke approximately (I forget) 10* BTDC on the compression stroke the decompresser raises the exhaust valve. If it was overlap the Intake would be opening as the ex is closing. Make certain you are turning the engine the correct direction, just as the ex bumps, turn past TDC both valves are closed adjust valves. The other way is adjust Ex when In fully open, In when Ex is full open.
 
Easier way to remember, at least for me, is, adjust intake as exhaust starts to open. Adjust exhaust as intakes starts to close.

Works for any four stroke engine, provided lash is set on cam base circle.
 
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