Predator 60363 dies when given throttle

[jtesh96]

Little background info: engine is a Predator 212cc 60363 engine with some light mods done to it. 18lb valve springs, removed governor, pod filter, and I put a real small motorcycle muffler on it because it was too loud for the neighbors with it being straight piped. Other than the muffler, all the mods were done by the previous owner. Also, when I got the kart, it ran fine before and after the muffler installation.

About a week ago I made the mistake of putting some bad gas in it. It ran roughly for a little while after that but soon it wouldn’t run or start at all. So after realizing the gas I was using was bad I drained the tank and stripped the carb and cleaned it out throughly. The main jet seemed okay but the emulsion tube had a little gunk in it. It was at this point I realized this was the stock emulsion tube and it is to my understanding when people modify these engines and put pod filters on, they increase jet size and use different emulsion tubes. I’m not sure if the main jet is stock, it’s hard to tell the difference in a .28 and .36 main jet just by looking at it without any reference. Regardless, I slapped everything together, put in some clean, fresh 100% gas, no ethanol, in the tank, and tried to start, but nothing. Pulled the spark plug and noticed it was the high performance autolite plug but was covered in carbon and not making spark. Due to the carbon on the spark plug, I decided to pull the cylinder head and check out the cylinder and valves. The carbon build up was pretty significant. I cleaned it out and went to the auto parts store and picked up a new NGK plug. Side note, I think the bad gas clogged the emulsion tube and caused the engine to run very rich and hence the carbon build up, hopefully that is the end of the story with the carbon build up.... but adding this info just in case it is related.

So that brings me to today. The engine will start but only if the choke is set just right which is just barely open. And I mean barely. Open it just a little more and the engine dies. But it’ll sit there and idle just fine all day. If I touch the throttle, engine dies. Unless I open the choke at the same time as I press the throttle. Then it goes like **** until I let go of the throttle and come to a stop and the engine dies because the choke is wide open.

Some things to note that I have noticed currently:
-the mixture screw does absolutely nothing. While the engine is idling, I can turn it all the way in or all the way out, the engine runs the same. This seems odd to me and I don’t know what it means. It is currently set at 1.5 turns out as a default.
-sometimes, not all the time, when I pull the cord to start the engine, it goes very stiff randomly and without warning. The handle gets ripped out of my hand and results in a lot of pain and cursing... If I have a firm grip on the handle and don’t let it slip out, I can literally drag the kart across the garage with the pull cord if it has gone stiff like this. This only happens about once every three pulls. This is definitely not normal and I also don’t know what this means. Also, there is no knocking in the engine when it is running so it’s not like the spark plug is hitting the cylinder.
-letting the engine warm up fully does not affect the engine dying. Also, the oil is fresh and oil level is good.

Sorry for the huge post. I am just baffled as to what is going on and thought the recent events might be important. Any help is greatly appreciated.

 

[JTSpeedDemon]

Cool, you have Predator Hemi! You must not be in California!

Here's my advice.
The tuning issue: The bad gas must've gummed up the idle/pilot jet, that would explain it dying without choke AND the screw not working. Take apart the carb and CLEAN every little passage! I personally work best with spray carb cleaner, but you can also strip all of the seals/gaskets off the parts and boil the carb in lemon juice.

The locking/kickback: Sounds like a starter issue. If you don't want to mess with it, I believe a new starter assembly is only like $20. Otherwise, I don't know the exact problem, but it sounds like a starter issue. When it locks and rips out of your hand, does it retract into the housing again?
Take off the blower housing. do you have a billet flywheel? They are VERY shiny and the fan is one piece with the flywheel. Lighter billet flywheels can amplify kickback issues if it's an engine and not a starter issue.

I hope this helps you figure this engine out.

 

[jtesh96]

I went ahead and took the idle/pilot jet out and sprayed it real good with some carb cleaner. I didn’t notice anything wrong with it before and I’ve definitely cleaned it at least twice this week trying to get it running. But I decided to do it again just so I could tell you that I did it and boom my problem is solved! It won’t run at wide open choke but dies much more slowly if I try that. I believe I read once that these engines are known to need a little extra choke to run sometimes. It’s also about 20 degrees outside so maybe the slight denser cold air is playing a role here.. but I’m not a scientist. On that note, about froze to death on a test ride around the block but very worth it since I could at least make it around the block again.

Thanks for the reply! You were spot on. Two minds always think better than one.

Also I swear, sometimes the best way to clean a carb is to just take it apart and put it right back together.
(That’s kind of a joke, don’t shoot me)

 

[BigWes]

Predators and starter kickback...once you start tinkering with the engine get used to it. I wear gloves and notice it the most on my hemi. Especially if the fuel mix is off. Usually happens if it's rich or flooded. It's not a starter issue. It's basically fuel detonation causing kickback.

Sounds like that carb is still dirty.

 

[JTSpeedDemon]

Cool! Glad you could determine the issue! As BigWes said, it sounds like it's still a little dirty, maybe run some proper size drill bits through the jets(by HAND) to get every last git of gunk out. Also make sure the passages behind them are clear.
Yeah, the carbs are tuned at the factory for generally good performance at different elevations and climates, but sometimes they do need a little re tuning for different circumstances. But I'd say the little tuning problem is still some leftover gunk.
Don't worry, it's not as bad as a ~34 yr. old carburetor! I've had to pull mine apart ~3 times and I STILL haven't worked all the kinks out! The PO really bubba'd my carb.
About the starter, does it still kick back? If so, does the rope retract again?

 

[jtesh96]

As for the starter, yes it retracts just fine even after being ripped from my hand. I’ve noticed that it only goes stiff if the spark plug is in and it’s on particular spot in the engine rotation. It seems to be when the cylinder hits TDC on either the exhaust stroke or intake stroke, hard to tell since it’s only stiff like this when it’s all put together. If I cautiously get just past that tough spot in the rotation, retract the cord completely, and pull the cord from there, the engine starts right up in one pull without ripping the cord from my hand. No weird sounds happen regarding the starting procedure or getting past that tough spot. Maybe I should just wear gloves from this point forward and suck it up?

 

[karl]

Please excuse me if this was already suggested,

TL/DR

Anybody suggest checking valve lash? You changed springs, what did you set the lash to? Did you use feeler gauges?

Too loose lash can cause a nasty kickback. (been there not fun)

My hemi with billet ARC flywheel has never kicked back in 3 years.

 

[Speed Assault]

these Clone parts are notorious for poor quality and installer not being careful.
One thing I have read that is Always over looked and not mentioned is that your needle seat can be bad. It's invisible to the naked eye but if its bad, it allows the engine to flood.

Get a new Needle seat ( Coned shaped Rubber needle head) $3.

5 minutes.
after i bought my New Engine I was always chasing this problem until I changed the needle seat.

 

[Flyinhillbilly]

I’m going to say that you should pull the pilot jet again and alternate between spraying it with carb cleaner, and running a piece of fine wire up through the center of it. Those can be a pita to get genuinely clean.
As far as the kickback goes I say check the valve lash since you had the head off.

 

[mckutzy]

-When you removed the gov.. was it all taken out or just the outside mech, ie. You didnt open the case???

-Did you replace any internals... Con rod and/or piston?
If not... Why replace the stock springs if stock rod??? You now dont have a gov for the conrod which may explode potentially(if you didnt already replace with billet).

-When replacing the carb after cleaning, did you replace the gaskets in the right order and also the right orentation?

-Is the insulator cracked?

-When you replaced the new jet after the new filter.. did you drill that jet to match a plug test or just match what everyone else typically does???

-When you say mixture screw... Do you mean a plastic Black headed Philips screw on top... or actually on the carb a small brass screw on the side near the insulator plate??

-Have you checked the flywheel key, to see if it might have sheared a bit?

 

[karl]

I hate to be that guy, but its been almost 3 months since the OP logged in ,

I think its probably repaired, replaced, or sold by now

no need to drag threads from the depths

 

[mckutzy]

Good point... I didnt actually see the date off hand...
Oh well... if buddy responds.. cool... if not, im sorry to hear that....