Newbie Engine Trouble

[ADDPJ]

Hi Everyone. First post. First GoKart. Carter Lightning been sitting for 10 years gx160/200 clone. Got it running. Had a issue so i had to take it apart. Took out the governor and oil sensor( since i already had it disassembled). I used a degree wheel and got it to what i believe to be 24/25* BTDC. Engine started. Put it in the cart. I have 2 issues making me crazy, and ill i can assume is that i somehow set the timing incorrectly.
1. The engine takes effort to start. Most of the time i either need to pull the cord a ton of times or turn the torque pulley to about 25*(assumed by feel) then its starts first pull. I can drive it shut it off and it will start no problem first pull, as long its warm or with in time of me getting it first started. I let it cool and i'm back to square one. Doesn't backfire, smoke, sputter, runs well. Flywheel is stock.
2. Kart has an electric start which worked before i took the engine out. Solenoid is new, fuses are new. Starter now turns the engine, I get spark, but never fires.

I'm assuming both issues are related. Sorry for the length on this and thank you in advance for you input

 

[madprofessor]

Pretty awful to be repeatedly yanking a pullrope when you have a working starter. What did you do to determine you were getting spark?
Laying spark plug against outside of motor? Screwdriver in the spark plug boot, jumping spark to ground? Etc.?
Not an expert on electric start, but that's what I'd be using to start it with. With fully charged battery, that is. Max engine rotation speed. Can't imagine why the starter would prevent starting if the spark's still there, unless just barely turning engine over.
My 212's have been using PVL flywheels that come with 28 degrees BTDC timing, and recommending 30 degrees. I personally use a 7.2 degree advance key, so 35.2 degrees total. I'd say advance your timing a few degrees,

 

[Karttekk]

What happens if you shoot a blast of starting fluid in the intake cold starts? If it fires right up you have a lean condition cold. You could have low compression. Do a wet/dry compression test and look for a significant change in readings from dry to wet. If that doesn't help recheck your valve adjustment or timing.

 

[madprofessor]

Karttekk, the comparison value of a wet/dry test sounds like a great idea in theory. Two questions, what is it, and how do I do it?
Only compression testing I've ever done is with the rubber nipple type gauge with a max pointer on it, held tight into the spark plug hole. Would love to have a little less one-person octopus arms method of doing it, especially with a comparison to look at.

 

[ADDPJ]

Hi Everyone, Thank you for the responses. Ill try and answer everyone here.

I just took another spark plug and plugged it in and let the wire hang on the frame. That's how i tested for spark.
Battery is new since the old one was 10 years old and even after leaving it on the tender the starter sounded like it was dying, so i retired it.
The Flywheel on that is stock and i set it for 24/25* which was spec for a GX160/200 clone. I will try 30*
I have not tried the start fluid test. I will try that as well and follow up. I do try to pump the throttle a few times before starting, that doesn't help.
Not sure what a wet dry compression test is. I do have a compression gauge and have tested for compression previously. I will check that again.
Just to make sure i have the correct info for valve lash.....008 on exhaust and .006 on intake, @ TDC of compression?

Thank you all again for the help. Ill check these items after work and followup.

 

[madprofessor]

"about 25*"............Just figured out what you mean by "torque pulley", and what's done. Seems you're saying you manually rotate the motor by twisting the drive pulley (on crankshaft) by hand to what you feel by the resistances is 25 degrees BTDC. Never gave any thought in the past to what degree of the rotation the compression release rides the cam shoulder, cracking open the exhaust valve for a few degrees.
Suddenly now I want to know how much pullrope you're using.
My motors used to have some kickback issues with a rope pull of about 36"-38", and then I found out my Predator 212's have 51" of rope. Started stepping back a little to give me room for a full (4') pull, and no motor has kicked back on me since.
Since your motor won't start with a pull unless you rotate the motor to a certain point, I have to believe you're not getting a long enough pull. Pull the whole length of the rope out and measure it, compare that to how far you've been pulling it. Try getting it started from any random position using that whole length of pull available, just don't break the rope.

 

[ADDPJ]

"about 25*"............Just figured out what you mean by "torque pulley", and what's done. Seems you're saying you manually rotate the motor by twisting the drive pulley (on crankshaft) by hand to what you feel by the resistances is 25 degrees BTDC. Never gave any thought in the past to what degree of the rotation the compression release rides the crank shoulder, cracking open the exhaust valve for a few degrees.
Suddenly now I want to know how much pullrope you're using.
My motors used to have some kickback issues with a rope pull of about 36"-38", and then I found out my Predator 212's have 51" of rope. Started stepping back a little to give me room for a full (4') pull, and no motor has kicked back on me since.
Since your motor won't start with a pull unless you rotate the motor to a certain point, I have to believe you're not getting a long enough pull. Pull the whole length of the rope out and measure it, compare that to how far you've been pulling it. Try getting it started from any random position using that whole length of pull available, just don't break the rope.

I will check on that. I did replace the pull rope as the original kind of disintegrated. Yes i have been turning the drive pulley on the crank side. Got tired of taking the pull rope side cover off. I'm kind of at the point where i can almost do tdc by feel i've done this so much. i do have a predator lying around i can see if i can swap the ropes. Ill measure as well. Ill alos try the other gentleman's suggestion on the timing.

I'm assuming both issues are related and i have to pull the rope so many damn times because the timing is off and eventually the flywheel is landing where it needs to be then it starts. Innerwebs' told me 20-25* and i actually asked in another group and (25*) was confirmed, so I'm going to try all of this this evening and check back. Thank you for your assistance.

 

[madprofessor]

A little concerned about that floppy valve lash setting. Manuals call for a loose setting, maybe that loose or a little less, but everybody I know who sets for performance uses .003" for both intake and exhaust valves.
If you set them again, just be sure and slowly rotate while looking closely at the exhaust valve. Be sure you actually see the point at which the exhaust valve cracks open and closed that tiny bit during compression release. TDC of compression stroke is the point at which to set valve lash, just be sure you're off of the compression release point or you'll get it wrong.

 

[ADDPJ]

A little concerned about that floppy valve lash setting. Manuals call for a loose setting, maybe that loose or a little less, but everybody I know who sets for performance uses .003" for both intake and exhaust valves.
If you set them again, just be sure and slowly rotate while looking closely at the exhaust valve. Be sure you actually see the point at which the exhaust valve cracks open and closed that tiny bit during compression release. TDC of compression stroke is the point at which to set valve lash, just be sure you're off of the compression release point or you'll get it wrong.

I will readjust this evening. Thank you for the assistance.

 

[Karttekk]

A wet dry compression test should tell you if the cylinder is sealing during the compression stroke. I bought a hose that fits my compression gauge and the spark plug hole/threads. Attach the tester to the engine then either crank the starter or pull the rope a few times until the needle on the gauge stops. Record the reading. Remove the tester, add a capful of oil in the cylinder, reinstall the compression tester then crank the engine a few times until the needle on the gauge stops. Record the reading. If both readings are within 10 lbs. or so you should be okay. If the readings are off by say 20 lbs. or so, there's an internal engine issue whether it's rings or a scored cylinder wall or even a leaky valve. As far as pulling the rope, if the engine is dialed in properly, (valves adjusted correctly, good compression, good spark, carb working right), you should only have to tug on the rope a short distance and the engine should fire right up. No need to pull the rope out 3 feet or whatever. A Robin Subaru engine and a Predator engine I had both started with a tug on the rope maybe a foot if that. Madprofessor is correct about the valve adjustment, you have them too loose. 3 0r 4 thousandths is what they should be set at COLD engine. pay attention to how he's telling you to find TDC. Turn the engine by hand with the plug out a few turns while watching the valves. One should open then close then the other should open then close then you'll see the exhaust valve "bump" open slightly then close, that the compression release working. I put a screwdriver or thin shaft in the plug hole so I can see when the piston is at TDC, it will rise with the piston. Report back with results.

 

[Karttekk]

Adding oil will temporarily seal the cylinder, this is the "wet" portion of the test.

 

[ADDPJ]

Hi Everyone,

Checking in. I tried to get in as much as I could. I will have more time tomorrow. I first tried to spray some starting fluid before I did anything. That didn't work. I lashed the valves to .003. I changed the timing to 30* and it started 8 times out of 10 on the first pull. The other 2 were 2 pulls. Definite improvement from where i was. I let it sit for about 35 min while i picked my son up from Tennis and when i got back started up on the second pull. Unfortunately still wouldn't start with the starter. I will check compression as specified tomorrow and check back in. Thank you everyone for the help

 

[madprofessor]

So glad my doctor has cleared me to use Advil again, because that starter of yours is giving me a headache.
If it turns out to be something simple, I'm going to be Rolaids pizzed awf at myself for not figuring it out yet.

 

[ADDPJ]

So glad my doctor has cleared me to use Advil again, because that starter of yours is giving me a headache.
If it turns out to be something simple, I'm going to be Rolaids pizzed awf at myself for not figuring it out yet.

We'll to make matters worse. I tried to pull the string on it again this morning before i left for work and it took 7 pulls again. As it gets closer to the 7th pull i can hear it getting closer to wanting to start. Will check compression today. Once it starts even if i run it for 10 seconds it will start fine until hours later after its been off for a while...

 

[Denny]

Check wiring or switch because it is definitely not mechanical. I think it is a bad switch personally.

 

[ADDPJ]

Check wiring or switch because it is definitely not mechanical. I think it is a bad switch personally.

The on/off switch on the engine?

 

[madprofessor]

Denny's onto something. If it's got a common keyswitch like a car's ignition, where you twist the key to start and release it, makes sense.
The key can be on to run, and break the run connection as the key's twisted to start. Spring release back to run position, run connection gets remade. So connection would always be solid while pullstarting, and broken while key's twisted to start.
Right or not, that's a good call.

 

[ADDPJ]

Denny's onto something. If it's got a common keyswitch like a car's ignition, where you twist the key to start and release it, makes sense.
The key can be on to run, and break the run connection as the key's twisted to start. Spring release back to run position, run connection gets remade. So connection would always be solid while pullstarting, and broken while key's twisted to start.
Right or not, that's a good call.

So just take the key out? or just disconnect the starter altogether. Is suggestion in relation to my pull start problem or just trying to use the starter in general?

 

[ADDPJ]

65lbs dry and 65 wet. It actually went to 70 wet and dropped slowly to 65

 

[Bansil]

No reference is to:

"off" position coil is grounded so engine is not able to run.
"Run" position coil is not grounded so when you pull rope engine will run
"Start" position coil should be NOT be grounded AND 12v power is supplied to solinoid to engage starter.

If switch is bad you could be trying to start engine with starter BUT connection is broken to coil and it thinks it is off and grounded

Disclaimer, my explanation is very simplified due to knowing your exact setup