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Old 02-17-2020, 10:15 AM
XRJSKX XRJSKX is offline
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Default Predator 212 wonít start after rebuild.

Okay guys this is my first post on this site but Iíve gotten a lot of valuable information from here in the past so I thought yíall could help. I have a predator 212 that I bought used on a old kart. It has always ran fine, started on first or second pull but it would only top out at 27 MPH and it cut off terribly cornering hard. I pulled the crankcase cover and removed the governor and oil pressure sensor and plugged the holes with a bolt/oring and some permatex and put it back together. I did have the head off to clean up some rough edges and just inspect it while it was apart but I did not have the cam or the valves out at any time. I reassembled the engine and have nothing but problems. Put fresh oil and gas in it no start, checked spark and it has strong spark, not solid blue spark but blue/orange. Adjusted valves at TDC and with the other method I found on here still nothing. Flywheel key is not sheared and cam was never removed so timing should not be an issue. Thought maybe carb was problem but have pulled all jets and thoroughly cleaned everything and it still will not even start with starting fluid. I did get it to pop twice when pulling it with throttle wide open but nothing since. Almost seems to me like itís not getting fuel but I have blown through the carb and it does not seem clogged. Any advice would be greatly appreciated Iíve tried everything I can think of and am about to the point of buying a new engine.

---------- Post added at 12:15 PM ---------- Previous post was at 11:56 AM ----------

Now if I spray a shot of starting fluid in the intake with the throttle open it will pop once or twice out the exhaust but nothing else and then it backfired through the intake and tried to catch fire so Iím done with it until i get some more opinions.
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Old 02-17-2020, 11:40 AM
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Did you get the valve lash set right? Are both of the rocker valves moving correctly?

It sounds like you have a timing issue.
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Old 02-17-2020, 12:00 PM
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I tried .005/.007 (int/exhaust) , .005/.005 and .003/.003 with no luck, I’m beginning to think I’m not setting the valves at the right location. I’ve been finding TDC with a screwdriver in the spark plug hole and I tried setting them with another method I found where you set them at different locations in the stroke both with no luck.
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Old 02-17-2020, 12:45 PM
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Let us see how you have your carb setup...
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Old 02-17-2020, 01:36 PM
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If I was having this issue I would
1) replace spark plug
2) remove carb and pull start at wot with starter fluid

Do this and check back
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Old 02-17-2020, 02:12 PM
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I have to find a new spark plug for it this week, havenít been able to find a match around town.
I tried removing carb and starting with starting fluid and it backfired out the intake and caught fire.
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Old 02-17-2020, 02:22 PM
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NGK Bpr6es.....
One of the most common ones... and thats ringing it off the top of my head....
It also happens to be what my truck uses...
Dont need special or fancy electrodes... just plain Jane NGK's
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Old 02-17-2020, 10:50 PM
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You should be able to find the generic spark plug at any appropriate store in town. If you are having trouble finding a spark plug, it means that you are looking for the wrong one
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Old 02-18-2020, 07:43 AM
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I’ve been a professional auto mechanic for over 25 years, and even now I NEVER assume that I did something right if it has a new problem after I’ve worked on it. I’m the first guy to tear it back apart and double check everything.
If I were you I’d double check the cam timing, set the valve lash, and check to make sure the carb and insulator garkets are oriented correctly. If all of this is in order it should start and run fine.
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Old 02-18-2020, 02:08 PM
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You still haven’t replaced the spark plug so don’t rule that out yet.

Did you set valve lash at TDC on the exhaust or compression stroke? If you don’t know the difference, that could be a problem.
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Old 02-18-2020, 06:12 PM
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Quote:
Originally Posted by KartFab View Post
You still havenít replaced the spark plug so donít rule that out yet.

Did you set valve lash at TDC on the exhaust or compression stroke? If you donít know the difference, that could be a problem.
I havenít been able to mess with it any more yet because of work, but that same thought hit me on the way to work this morning. This is my first time having to set valves on a small engine like this and I honestly donít know the proper way to find the location to set them at.
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Old 02-18-2020, 06:43 PM
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At TDC the piston is at the TOP of the cylinder. For the compression stroke it is at the bottom.

Just because the valves are closed doesn't mean the engine is at TDC.
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Old 02-18-2020, 07:18 PM
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I have been judging TDC by a screwdriver in the spark plug hole to determine to the topmost point, gonna try to go get a new plug on my break tomorrow.
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Old 02-18-2020, 07:24 PM
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Quote:
Originally Posted by Solomonster212 View Post
At TDC the piston is at the TOP of the cylinder. For the compression stroke it is at the bottom.

Just because the valves are closed doesn't mean the engine is at TDC.
Close.
The piston is not at the bottom on the compression.

There's tons of videos on youbube that explain it very clearly so take a gander there.

Tdc is where the spark happens. Both valves are closed and piston at top.
Then the explosion moves the piston down.
As the piston reaches the bottom and starts it's way back up the exhaust valve opens and the piston pushes the spent charge out. This the the exhaust stroke. At the end of this the piston is back on top, but this is not TDC.
the exhaust will close and the intake valve open as the piston starts moving back down sucking in a new fresh fuel air mix.
At the bottom the intake will close and the piston starts back up in the compression stroke.
Back at the top with both valves closed the spark ignites and we start again.

Remove the spark plugs and you can carefully feel the piston with a screwdriver as it rolls over the top.

Watch the valves and you can tell which is TDC and which is not.

If you pull the fan shroud you can also see the magnet pass by the coil. That's a quick way to see if the piston is at top or bottom. It lines up twice so you still need to watch the valves to be sure.
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Old 02-18-2020, 07:35 PM
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Well, I know when my engine is at TDC. And I know when it's not. Enough said there for sure. ��

---------- Post added at 08:35 PM ---------- Previous post was at 08:34 PM ----------

Lol
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Old 02-19-2020, 07:45 AM
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One almost foolproof wat to set the lash is to roll the engine until one valve is all the way open, and adjust the one that isn’t. I often do it that way on V8’s and still do it that way on these little engines.
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Old 02-19-2020, 04:54 PM
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Unless you put them stupid clips on your chevy rocker arms and adjusted while engine was running of course always had a couple pop off when you touched the throttle.....oil everywhere

Haven't used those for 20 years
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Old 02-19-2020, 08:37 PM
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Quote:
Originally Posted by Bansil View Post
Unless you put them stupid clips on your chevy rocker arms and adjusted while engine was running of course always had a couple pop off when you touched the throttle.....oil everywhere

Haven't used those for 20 years
Those things are a scam. They never stay on.
I used to have an old valve cover with a strip cut out of the middle where I could get to the rocker nuts. Then I figured out that I could roll it through with a ratchet and set them faster than I could R&I a valve cover twice to set it running.
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