Club Car DS backfire out carb

[muckinfonkey]

Here is the proper view of the flywheel and coil at TDC. Still struggling here.....

- Confirmed bright white spark
- removed ground from Rev Limiter
- Getting fuel, spark plug is wet
- rotating clockwise at clutch (it's a 2000+ cart)
- Valves adjusted to .005
- Compression is 150+

Still just spits and sputters and backfires fireballs from the Carb....

This is what I get for starting to feel confident working on these things for 20+ years...... never seen anything like this.....

[charlie99]

Re-reading above, I'm not quite sure how you verified the flywheel key without removing the flywheel.

Could maybe be broken or loose rivets on the plastic cam gear?

If it were me, my next step would be to check the ignition timing (assuming you have a timing light). You can do this in the cart if you remove the plastic shroud (not the sheetmetal):
* put piston at TDC of compression stroke
* Paint one flywheel fin, and mark it's position on the sheetmetal
* Hook up timing light; using the strobe, mark the position of the painted fin on the sheetmetal.
* measure between the two marks. Some fancy timing lights have a dial you can use for this.

[muckinfonkey]

Originally Posted by charlie99

Re-reading above, I'm not quite sure how you verified the flywheel key without removing the flywheel.

Could maybe be broken or loose rivets on the plastic cam gear?

If it were me, my next step would be to check the ignition timing (assuming you have a timing light). You can do this in the cart if you remove the plastic shroud (not the sheetmetal):
* put piston at TDC of compression stroke
* Paint one flywheel fin, and mark it's position on the sheetmetal
* Hook up timing light; using the strobe, mark the position of the painted fin on the sheetmetal.
* measure between the two marks. Some fancy timing lights have a dial you can use for this.

Doesn't the location of the magnet in relation to the coil give me the same information about whether it has skipped time or not?
I agree though I don't have definitive confirmation of that keyway sharing or not.

[Fairtax4me]

If the nut that holds the flywheel on is tight then there's no real reason to suspect the ignition timing is a problem.
Did this just start happening or did it happen after doing some kind of work on the cart?
Is this the original engine for the cart? The early FE290s were counter clockwise rotation, so if the engine has been replaced at some point it's possible its rotating the wrong way.

Are you sure the cam is turning? The rivets that hold the gear on the camshaft can shear off. Remove the valve cover and spin the engine and make sure both valves open properly in sequence.
I would also try and open up the valve clearance to around .010 and see if it will then start and run.
Lastly I would do a leakdown test to verify there is not a valve or seat problem.

[muckinfonkey]

Originally Posted by Fairtax4me

If the nut that holds the flywheel on is tight then there's no real reason to suspect the ignition timing is a problem.
Did this just start happening or did it happen after doing some kind of work on the cart?
Is this the original engine for the cart? The early FE290s were counter clockwise rotation, so if the engine has been replaced at some point it's possible its rotating the wrong way.

Are you sure the cam is turning? The rivets that hold the gear on the camshaft can shear off. Remove the valve cover and spin the engine and make sure both valves open properly in sequence.
I would also try and open up the valve clearance to around .010 and see if it will then start and run.
Lastly I would do a leakdown test to verify there is not a valve or seat problem.

I will need to look at the number on the motor to confirm but I'm fairly certain it's the original engine.
Yes the valves are functioning when the motor spins.
If I had a valve that wasn't seated properly enough to run the cart would I still be getting 150lbs of compression?
I'm not sure what a leak down test is....

[CP241]

Backing up a bit...

Post 1 carb is new and has been cleaned. Post 11 spark plug is wet.

Is this an one mikuni carb or an aftermarket? And what brand/model spark plug is installed?

While 150 compression isn’t “great” it should be plenty for it to run. Though these cylinders never seem to show signs of wear, the intake valves do tend to wear on these over time, and 21 years is a long time on a small motor like this. This is theoretical but if the intake valve is worn, I could see how it has been adjusted back to spec fir lash, though now the lift and duration will be affected and possibly not let “enough” air in. Both reducing the compression slightly (because there’s less air to compress) and affecting the air/fuel mix.

There’s no evidence for this without pulling the head, and this maybe throwing a dart in the dark, but could be a possibility.

[Golf cart guy]

Had one the customer wired the starter wrong and it was turning the motor the wrong way. Seems you kinda said you checked that, but Id double check, and its a simple check.
The CC gas is a simple motor

[Fairtax4me]

Originally Posted by muckinfonkey

I will need to look at the number on the motor to confirm but I'm fairly certain it's the original engine.
Yes the valves are functioning when the motor spins.
If I had a valve that wasn't seated properly enough to run the cart would I still be getting 150lbs of compression?
I'm not sure what a leak down test is....

I’ve had intake valves adjusted too tight and had good compression when cranking but would sputter and not start, and spit back out of the carb.
A leak down test is similar to a compression test except you apply 90-100psi air pressure into the cylinder at TDC. There are some special tools for this, but most compression testers have an adapter to hook an air hose to the hose that threads into the plug hole. It has to be set perfectly at TDC or else it will just spin the motor over. Useful for finding burned or bent valves or valves that are hung open but appear to be closed. Put air in, listen to where it comes out.

Other though is that something could have built a nest in the tail pipe or the muffler is clogged. Back pressure in the exhaust will cause similar symptoms even with proper compression.
150 psi is not low, but just tossing out some ideas of things I would check if I could put hands on the engine.

[lockman1]

Just Curious... since it was never really mentioned,

Do you have the intake hose (and air box w/filter) connected while trying to start it?
Kawi FE engines don't start, or run very well without it hooked up...

[muckinfonkey]

Update......
Worked on this **** thing for 6 hours tonight and still no luck. I haven't responded individually to a few of everyone's post so I will try to hit as many as I can here....

1. Got the flywheel off tonight and confirmed that the key is still intact and no other damage is noted.
2. Took the head off.... The valves were dirty but not terrible.... I lapped them and they cleaned up great....still same problem
3. This is the original engine, it is turning clockwise.
4. I have not done the leak down test I don't have the right equipment for that but I am getting about 150 to 160 lb of compression
5. I've run it with the air box on and the air box off it's the same either way
6. The valves are opening and closing as the cart cycles
7. With the spark plug out I get a good steady bright white spark
8. Suspecting possibly a plugged or partially plugged muffler I ran it with and without the muffler.... Exhaust is flowing out of the muffler
9. I took the ground wire off the limiter


I believe my next step is to install the old carburetor and the old fuel pump once they are found. I'm shooting in the dark at this point.

I really appreciate all the responses, at this point I'm suspecting that it's something dumb that's right in front of my face.