Predator 212 wont fully start

[BaconBitRacing]

I’m going to open it up and check the internals. Thanks all.

Great, pictures please!

 

[Vash]

Bad gas... Too much air... Pulling the engine apart ain't hard and if you don't damage the gaskets u can re use them for testing. I pulled apart one cleaned the heads and valves checked the cam and had it back together and running in about 3 hours. If you pay attention where it came from it will go back together.

 

[Karttekk]

What do you mean when you say you "messed with the carb?" Why did you mess with the carb and how did you mess with it? You might have the gaskets installed wrong, there could be crud in the gas tank either blocking fuel flow or keeping the needle open in the carb inlet seat. Do you have a pinched fuel line? Maybe a one way fuel filter on backward? Need more information. Too narrow of a fuel line? Stale gas? Water in the gas? Put a new spark plug in it. Dunno.

 

[Karttekk]

The coil could be on it's way out too. Don't rule out an electrical issue. Pull the spark plug, attach the coil wire to it, ground the plug and pull the rope. Are you getting a strong, blue spark? Check for cracks in the coil wire. Check all of your grounds.

 

[Karttekk]

Check the oil level. If you're low on oil the low oil switch will kill the engine or not allow it to start. Something to consider.

 

[Master Hack]

We don’t have crystal balls

I’ve heard of brass balls, but never crystal! Is that one of these new gender things?

 

[panchothedog]

They can only be exposed in the gender neutral bathroom.

 

[LtDansNewLegs]

Opened up the valves and checked the rods and recalibrated the valve gaps. Took off the fly wheel and didn’t see anything wrong so put it back on. Realized I was missing the stock carb insulator since I switched from a Mikuni to a stock carb and installed that. With those 3 changes, one of them did the trick and now it’s idling like a charm. Only problem is it cuts out at half throttle, but I’ll save that for another day. Thank you everyone for your help and insight!

 

[Karttekk]

There you go!

 

[Master Hack]

Vac leak….

 

[panchothedog]

I've heard that without the insulator they won't run with the stock carb. So glad to hear you solved the problem. Usually turns out to be something basically simple, but none the less Overlooked.

 

[LtDansNewLegs]

All,
I wanted to update you on the real issue that was causing this problem. The camshaft exhaust lift had been hitting something and smoothened itself down to where there was no lobe. I measured the lift on the exhaust and it was .003 with the intake lobe lift being .266

 

[BaconBitRacing]

All,
I wanted to update you on the real issue that was causing this problem. The camshaft exhaust lift had been hitting something and smoothened itself down to where there was no lobe. I measured the lift on the exhaust and it was .003 with the intake lobe lift being .266

Wow that’s interesting, next time you’re going to clearance the crank, aren’t you?

 

[Karttekk]

What do you mean by the "camshaft exhaust lift was hitting something?"

 

[Denny]

I’d like to see pictures of the carnage.

 

[BrownStainRacing]

I’d like to see pictures of the carnage.

Yea me too. Cause theres way no that can happen with these pushrod engines.
1st, the compression release is on the exhaust lobe. If you lost .015" on the exhaust lobe, that means you now have .015" + valve lash on the exhaust side, the compression release would NOT work when you try to pull start it, and will bruise your hand, wrist, if not break it..... you will give up really quick and try to figure out why it's so hard to pull. So this .003" lobe lift doesn't make sense.
Now, when you start getting around .025" valve lash on the exhaust side, the pushrod will pop off the rocker arm and not open the exhaust valve. So the intake charge will come thur the intake valve seat, because the intake valve will open, get compressed, and then what??? It can't go out the exhaust because the pushrod is off the rocker arm. again you would not be able to pull the rope.

Something jus dont jive with this.

 

[panchothedog]

BrownStain. I know I am kinda hijacking here, BUT if one were REchecking
valve lash and one cam lobe had .265" lift and the other lobe was so worn down that it only had .003" lift HOW could you miss that while adjusting the valves. Maybe a misunderstanding somewhere along the line.

 

[BrownStainRacing]

BrownStain. I know I am kinda hijacking here, BUT if one were REchecking
valve lash and one cam lobe had .265" lift and the other lobe was so worn down that it only had .003" lift HOW could you miss that while adjusting the valves. Maybe a misunderstanding somewhere along the line.

Exactly!!!!
One would have to reset valve lash about every .015"-.025" of lobe wear, to keep from breaking their arm.

But how many times would one have to do that to get down to .003" lift, from .265".

Now, I'm not the smartest guy, but if something ain't working after a couple or 3 times, I might wanna change what I'm doing.

I've seen my share of cams wear out the exhaust lobe, and they all pop really bad, and throw flames out the intake (backfire). And super hard to pull the rope.

I'm starting to think he has miss worded something. I jus can't see this happening.

 

[LtDansNewLegs]

Nope. No misswording. I threw out the cam otherwise I’d attach a pic. It basically had zero lift which may explain why it would choke out and shut off after giving any gas. I also never took out the valves or push rods, just adjusted the valve lash to what was TDC. I know much more about the engine now to just take them all out, but at the time, I didn’t.

 

[BrownStainRacing]

That's it. Learn as you go. Now you know what to look for.