Help! Predator 212 won't start no matter what I do

#1
So I have a non-hemi 212 predator, and it ran fine before I started doing mods to it. When I installed the stage 1 kit from GPS, I couldn't run the engine off of choke for more than a few seconds, and it would eventually die out anyway. I replaced the stock carburetor and it still did the same thing. Just yesterday I got a 22mm mikuni and slapped it on the engine, tried to start it, and it would still not start. I am at a complete loss right now, and have no idea what to do.
- has spark but the spark plug is wet (see picture)
- head is in similar condition to the spark plug (tiny bit of wetness and completely black
- key is not sheared on flywheel
- turns over fine, fights back
I've read multiple forum posts on here and people here seem to be really knowledgeable about this stuff, any help is appreciated
 

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mustangfrank

Well-Known Member
#2
Wet and black indicates too rich but your first symptom of dying off choke indicates lean, likely a plugged pilot, float issue, etc. Now it won't start at all? Did you leave the governor alone/stock?

Put a fresh plug in it and double check whatever you did to the carb, I'm assuming the main jet was replaced? I'd go back to whichever one it ran well with, you're not going to gain anything with a Mikuni on an otherwise stock engine anyway.
 
#3
Wet and black indicates too rich but your first symptom of dying off choke indicates lean, likely a plugged pilot, float issue, etc. Now it won't start at all? Did you leave the governor alone/stock?

Put a fresh plug in it and double check whatever you did to the carb, I'm assuming the main jet was replaced? I'd go back to whichever one it ran well with, you're not going to gain anything with a Mikuni on an otherwise stock engine anyway.
I do plan to put a fresh plug in, getting one tomorrow hopefully
I just did the governor removal to go with the mikuni, not planning on running it long with the stock rod/flywheel
mikuni jets are stock, needle adjustment is stock
hope this helps
 

toomanytoys

Well-Known Member
#4
I'd say your best bet would've been to get it to run on the stock carb first then move onto other mods. You've thrown a whole other variable into the mix.

Did you buy a real mikuni or a Chinese copy?

The chikuni carbs are real hit or miss from my research.
 
#5
I'd say your best bet would've been to get it to run on the stock carb first then move onto other mods. You've thrown a whole other variable into the mix.

Did you buy a real mikuni or a Chinese copy?

The chikuni carbs are real hit or miss from my research.
I bought a chikuni for reason of cost, I know the geniune ones are reliable as hell, if i had the money i would definately go for that
i dont think its a carburetor issue, since i went through 3 different stock carbs (all working, cleared jets etc.) still wouldnt run at all. even before i removed the governor it still had the issue of staying running
maybe its something wrong with the top end? (valves, huge wet carbon residue on combustion chamber, valves need to be lapped) or could be something as simple as the spark plug being bad, i have no idea what it could be
unrelated question, but since this is my first mikuni type carburetor, what is a good adjustment for the needle clip? i know it takes some fiddling but any recommendation helps
 
#6
Your plug looks fouled and if it is it will not run and most likely will not fire as the black carbon will conduct the spark to ground without jumping the gap. Even it it sparks out of the engine under compression it will not. Pick up a few cheap plugs so if another one fouls you dont have to go back to the store to get another. Toomanytoys is correct when you change something and it does not work, don't go changing more stuff, instead back off the changes one by one. If you took the engine apart to remove governor now there are more things like cam timing and valve adjustment you may have inadvertently messed up.
 
#7
Your plug looks fouled and if it is it will not run and most likely will not fire as the black carbon will conduct the spark to ground without jumping the gap. Even it it sparks out of the engine under compression it will not. Pick up a few cheap plugs so if another one fouls you dont have to go back to the store to get another. Toomanytoys is correct when you change something and it does not work, don't go changing more stuff, instead back off the changes one by one. If you took the engine apart to remove governor now there are more things like cam timing and valve adjustment you may have inadvertently messed up.
well it doesnt seem like i messed up, i did go back to just the stage 1 kit on my 212, and while i was taking it apart, i did a compression test. showed about 39 psi with compression release so I think that is the issue, should i replace all of my gaskets, or should i replace the rings?
 
#8
I would first check your exhaust valve lash. You should have around 60psi compression if exhaust valve is set correctly. make sure to set it a few degrees ATDC of the overlap stroke.
 
#9
By the way the compression release is anything but precise. It is possible that the exhaust is set correctly and the compression is only 39PSI. If so you could open the clearance of the exhaust from .003 to .004-.005.
 
#10
By the way the compression release is anything but precise. It is possible that the exhaust is set correctly and the compression is only 39PSI. If so you could open the clearance of the exhaust from .003 to .004-.005.
ill check the lash tomorrow, ill also check to see if the rings are worn at all once i try out the lash change
 

mustangfrank

Well-Known Member
#11
Again, take smaller bites and chew...how did the rings wear out if it hasn't really run since before you modded it? I don't recommend reusing head gaskets unless you really know what you are looking at, I'd have a new one on hand before you go down that rabbit hole. Sounded like you already had the head off if that's how you were looking at the combustion chamber, that's another potential source of compression loss.
 
#12
Again, take smaller bites and chew...how did the rings wear out if it hasn't really run since before you modded it? I don't recommend reusing head gaskets unless you really know what you are looking at, I'd have a new one on hand before you go down that rabbit hole. Sounded like you already had the head off if that's how you were looking at the combustion chamber, that's another potential source of compression loss.
yeah, i had the head off before to inspect it after i saw those readings, ill pull it again and check the gasket and see if its damaged. i will probably just replace it
 
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mustangfrank

Well-Known Member
#13
ok, ill check the head gasket before i do the exhaust lash
Maybe I should have stayed on the sidelines, I said that to try to prevent you from removing the head if you haven't already when you mentioned the rings. Check and set the lash as @ole4 said and see where you are then, he knows far more about these engines than I do!
 
#14
Maybe I should have stayed on the sidelines, I said that to try to prevent you from removing the head if you haven't already when you mentioned the rings. Check and set the lash as @ole4 said and see where you are then, he knows far more about these engines than I do!
my bad lol, i had already taken the head off before to remove the governor but wasnt sure on the head gasket's condition. ill set the lash like @ole4 had told me and ill tell you guys what happens
 
#15
I gave you bad info, sorry, you set valves a few degrees ATDC on COMPRESSION stroke. On overlap both valves are slightly open.
 
#17
I gave you bad info, sorry, you set valves a few degrees ATDC on COMPRESSION stroke. On overlap both valves are slightly open.
so i just adjusted it to .005, tried to start, and nothing happened. redid compression test and now apparently i have only 30 psi of compression
 
#18
So you are at .005 on ex and .001-.003 on intake correct Back when the engine was running fine was the motor harder to pull over with the pull starter than it is now? You have a new plug and spark correct? Would you happen to have starting fluid?
 
#19
So you are at .005 on ex and .001-.003 on intake correct Back when the engine was running fine was the motor harder to pull over with the pull starter than it is now? You have a new plug and spark correct? Would you happen to have starting fluid?
i'd have to check my intake but i remember setting the lash to .003. when it was bone stock it was harder to pull over, and i had it sitting for a while before i got my frame. i got the stage 1 kit and it started running bad, then now it just doesn't start. i just got my new plug and I do have starting fluid
 
#20
Turn off gas so carb does not get fuel. You can drain float bowl on mikuni with the screw on the bottom of the float bowl. Open throttle and give a two second spray of starter fuel into carb. Pull the starter and see if it shows any signs of life. You may want to hold throttle open a slight bit when cranking.
 
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