Par car slow all the time

[AGELE55]

Originally Posted by Tankercart

gloved finger up the tail pipe.... lol nice. So I took the cylinder off and used the manual lochlin already posted for measuring and inspection. Sadly didn't find anything substantial to determine the cylinder is out of round. A little larger at the bottom of the cylinder but still well within limits. The ring gap is larger. The manual states .007-.023, and mine is .046.

I placed the cylinder on level surface and set the head on top with no gasket in-between. I do notice a very slight rocking one direction and not the other....

After re-examining the piston it's a little more worn than I thought. The skirt has some irregularities. I could buy a new one for 50 bucks and hope for the best.... But I talked to a guy today who told me he'd bore the next OS and mill the head ($70) if I got him the bigger piston and rings. All in $140 dollars. That's 20 dollars cheaper then the new cylinder, but I'd still have to clean all that carbon out of the exhaust port... what do you guys think? .020? worth it?

Side note: the piston connecting rod has some radical play. is that normal? I think there's a roller bearing in there, and probably shouldn't have slop, but it's a 30 year old engine.

For the $ difference, I’d probably go with a new cylinder. .046 is pretty loose. Not sure if it’s 65psi loose, but new parts at least remove all doubt.
So... define “radical play”. Or hopefully you meant radial play...lol

[Tankercart]

Originally Posted by AGELE55

For the $ difference, I’d probably go with a new cylinder. .046 is pretty loose. Not sure if it’s 65psi loose, but new parts at least remove all doubt.
So... define “radical play”. Or hopefully you meant radial play...lol

Darn... I was hoping you were gonna say bore and mill... I weighed it pretty heavily considering my budget. I figured if I got the new cylinder (163) then I need a new piston (50) for a total over $200. The plus would be I don’t have to chisel the carbon. The negative is I’d still need to mill the head to be sure that’s not warped. OR i order and oversized piston/rings and bore and mill for a total of $150. The negative is I have to be so careful getting that carbon out the exhaust port unless the technician does it for me idk... the positive is it increases the power slightly and I can brag about it lol.

Yeah radial play sorry. Forward and aft motion.

[AGELE55]

Ultimately, - your cart and your money = your decision...lol
I’d be really curious to see the results of a wet compression test before you replace or rework the cylinder.

[73eldo]

I have not heard good things about the quality of the replacement cylinders lately but I know that my original lasted a long time so I had mine machined. In theory there is nothing wrong with properly machining one but you get a new one that maybe wasn't machined that well to start with or not very good metal?

[Tankercart]

I am a fan of the wet test because it easy. But I already pulled the cylinder off and committed to machining. I did do a bunch of research on the wet test. Agele55 mentioned it was originally used for 4 stroke engines with valves. Some people do wet test 2 strokes BUT there’s a bunch of people who say “well of course the compression increases” but it doesn’t guide you in troubleshooting and some guys state it ruins your compression tester.

73eldo. Yes I agree.. new parts can be questionable. After doing a bunch of research on the reed valve.. Man there are a bunch of poorly machined reviews for multiple sellers.

[Tankercart]

Well fellas... she’s runs! Had the cylinder bored .20 over and the head milled. New oversized piston and rings. Goes way faster about 20 mph. Noticeable slower going up hill but the more it ran the more deeper the belt got into the drive clutch. I suspect some rust in both the secondary and primary clutch. Sadly the compression has not changed!!!!! It still reads 65 psi.

The cart seems to take a few seconds to get going. The overflow of the carb leaks more fuel than I like. It’s pretty constant. The carb is new. Does anyone know how to set these Chinese carbs?

[AGELE55]

Originally Posted by Tankercart

Well fellas... she’s runs! Had the cylinder bored .20 over and the head milled. New oversized piston and rings. Goes way faster about 20 mph. Noticeable slower going up hill but the more it ran the more deeper the belt got into the drive clutch. I suspect some rust in both the secondary and primary clutch. Sadly the compression has not changed!!!!! It still reads 65 psi.

The cart seems to take a few seconds to get going. The overflow of the carb leaks more fuel than I like. It’s pretty constant. The carb is new. Does anyone know how to set these Chinese carbs?

Well... well.... uh...
-Way faster is good.
-65 psi is a mystery.
-Taking a few seconds to get going could be crankcase seals. My G1 had issues getting going until I cahanged them.
The carb should not overflow at all under normal circumstances. Maybe the float is a bit out of adjustment (too high)so as it never seats the needle valve... which possibly could relate to the slow start?... and maybe the uphill thing? too much gas?
At any rate, you have definitely made progress! Keep on keeping on.

[73eldo]

Leaking fuel can't be good how well the engine runs. Its likely pretty rich and rich doesn't make power especially after you get some build up which you will running rich.

I have not messed with the cheapo carbs myself but what I hear is its a 50/50 chance that they will work and if they don't there generally isn't anything you can do to fix them.

What do you have for a fuel pump? IF its electric you may just have too much pressure.

Since this is a par car I assume this is the Walbro style with the float bowl? Leaking gas with that style implies that you have a float and or needle and seat issue. That's fairly easy to test but then depending on what you find if it can be fixed or adjusted.

I would pull the carb and try to drain all the gas out of it. Grab a short piece of new hose to the inlet and blow in it. With the carb in the normal direction you should be able to blow air in it. Flip it upside down while blowing. It should stop. If it doesn't there is your problem.

Assuming it didn't shut off take the bowl off and do the test again and see if maybe pressing on the float a bit helps? IF it does is that because the float is hitting something? If so can you see any way to not make it hit? Grind off what its hitting? The plastic floats you usually can't adjust by heating them so you have to figure out another way to make them work.

If its not hitting anything then its got to be an issue with the needle and seat. These likely have a small O ring shoved up in the bore as a seat. Maybe the O ring fell out or wasn't pressed in straight and seated?

[Tankercart]

I’ll take it off an inspect the needle/float system. Does anyone have any advice on setting the idle adjustment/ air fuel screws.

[AGELE55]

Originally Posted by Tankercart

I’ll take it off an inspect the needle/float system. Does anyone have any advice on setting the idle adjustment/ air fuel screws.

Gently bottom it out, then back it out 1-1/2 turns.