STUMPED full rebuild and still 60 psi of compression

[Ascender]

2pg two stroke was running really slow and had 60 psi of compression, I did a complete top end rebuild, new jug, piston, rings, head gasket etc, I am STILL only getting 60 psi of compression?????? it starts right up and runs but its very sluggish on hills! I have tried two different compression gauges, one is new, and the piston is in the right way. I also inspected and changed reed valve seals. I am stumped... Could I have a bad head? The vent tube also pours gas out of it, I am going to order a new carb today.

[CP241]

Couple things, first, (just to make sure) hold the carb butterfly all the way open with your hands while cranking during compression test or it will read low. Secondly, it can take a little run time for the rings to seat. Once seated compression will increase.

Did you install the rings the correct direction? I don't knowk about the 2pg specifically, but most 2 stroke motors (or motors in general) the top ring is different from the 2nd ring. And they CAN be installed upside down. There should be a dot, or a letter, or some type of a mark indicating "this side up" on the ring. Both of which will affect compression.

Did you replace crank seals while it was apart?

[Lochlin]

I am not an EZGo guy but know other 2 cycle carts pretty well. If the below is not correct someone will chime in

Man, 60 psi is low. That thing shouldn't be running at all. I know you have tried a couple of different gauges but 60 psi still sounds too low to run and I suspect that there is something up with those readings.

Fuel coming from your vent tube is a concern as that means that your float bowl is flooding. Did you try adjusting your float a bit? If your carb is flooding out it can cause sluggish running.

[cart around]

Starting right up, and running, but still having 60 psi on two gauges leads me to believe that it's your technique, not the actual compression.

Sluggish on hills points to a clutch problem.

An overflowing vent points to a float that needs to be adjusted.
Sometimes overtightening the bowl nut will crush the bottom of the bowl. That will block the cross drilled holes in the stem causing the gas to also spill out of the vent. Depending how badly they are blocked, the cart won't run at all, or will run poorly from a lack of fuel.

The rings are Keystone type. The bevel side goes up, and the ends wrap around the alignment pins in the ring grooves. Did you check the ring gap before installation? This manual will have all of your specs.

[Ascender]

Originally Posted by cart around

Starting right up, and running, but still having 60 psi on two gauges leads me to believe that it's your technique, not the actual compression.

Sluggish on hills points to a clutch problem.

An overflowing vent points to a float that needs to be adjusted.
Sometimes overtightening the bowl nut will crush the bottom of the bowl. That will block the cross drilled holes in the stem causing the gas to also spill out of the vent. Depending how badly they are blocked, the cart won't run at all, or will run poorly from a lack of fuel.

The rings are Keystone type. The bevel side goes up, and the ends wrap around the alignment pins in the ring grooves. Did you check the ring gap before installation? This manual will have all of your specs.

Thanks for the reply... I am not sure how else i can check the compression. I pulled the carb and the exhaust and rechecked the compression with very little change. I was able to see the rings through the exhaust port and i am pretty sure the bevel side it towards the head, I am getting ready to go down and recheck that. I am going to order a new carb, Both of the clutches are new and so is the belt. I am thinking the carb is flooding causing it to fully run. I haven't started to look at the ignition system yet. The 60 psi is just what gets me but i do agree that it should not run with that low of compression. I am going to go to autozone and rent their gauge and see if there is any different but i check my two gauges with an air compressor and they both read correct.

[CP241]

Originally Posted by Ascender

Thanks for the reply... I am not sure how else i can check the compression. I pulled the carb and the exhaust and rechecked the compression with very little change. I was able to see the rings through the exhaust port and i am pretty sure the bevel side it towards the head, I am getting ready to go down and recheck that. I am going to order a new carb, Both of the clutches are new and so is the belt. I am thinking the carb is flooding causing it to fully run. I haven't started to look at the ignition system yet. The 60 psi is just what gets me but i do agree that it should not run with that low of compression. I am going to go to autozone and rent their gauge and see if there is any different but i check my two gauges with an air compressor and they both read correct.

If you buy a new carb, get an OEM one. Any other carb will just leave you chasing your tail because aftermarket carbs tend to create more problems than they actually solve. You can get an OEM carburetor here https://shop.txtsv.com/carburetor-bv24-18-98

[Ascender]

Originally Posted by CP241

If you buy a new carb, get an OEM one. Any other carb will just leave you chasing your tail because aftermarket carbs tend to create more problems than they actually solve. You can get an OEM carburetor here https://shop.txtsv.com/carburetor-bv24-18-98

Thanks for the suggestion I will order one. I just pulled the engine, the rings were upside down so i filled them over still no change. i installed the old head gasket and got 80psi gained 20 psi, so i am thinking it has to be in the head. I put a straight edge on it and everything looks straight. Is there anyway to do a leak down test?

[Lochlin]

You can try doubling up on the head gaskets. If the head / cylinder aren't still perfectly milled after all of these years sometimes another gasket will rectify things.

Leak downs can be done a couple of ways, the entire engine or just the top end. With the latter, which is all you probably need, just get a good compression reading, leave the compression gauge in place and leave things sit. Your compression should hold steady for hours.

Simple additional thought...are you torquing your bolts to spec? Too little and things will leak. Too tight and you'll warp the head gasket. Also, I am not sure about your cart but a lot of motors require a specific sequence of tightening the head bolts. Would anyone know if that's the case with a 2pg?

[Ascender]

Originally Posted by Lochlin

You can try doubling up on the head gaskets. If the head / cylinder aren't still perfectly milled after all of these years sometimes another gasket will rectify things.

Leak downs can be done a couple of ways, the entire engine or just the top end. With the latter, which is all you probably need, just get a good compression reading, leave the compression gauge in place and leave things sit. Your compression should hold steady for hours.

Simple additional thought...are you torquing your bolts to spec? Too little and things will leak. Too tight and you'll warp the head gasket. Also, I am not sure about your cart but a lot of motors require a specific sequence of tightening the head bolts. Would anyone know if that's the case with a 2pg?

i doubled the gaskets still that same, I torqued them to 18 ft lb in a star pattern, when i torqued them to 28 that is when i got the extra 20 psi.

[CP241]

Originally Posted by Ascender

i doubled the gaskets still that same, I torqued them to 18 ft lb in a star pattern, when i torqued them to 28 that is when i got the extra 20 psi.

Take a full sheet of 320-400 grit sandpaper and put on a FLAT surface. not plywood with bumps but something flat and level. Hose it down with WD40 and using light pressure, drag the head in a figure 8 pattern on the sandpaper. Just a lap or two. If there's any imperfections in the head, that can sometimes help it to stand out. IF so, keep doing this until everything is even, smooth, and shiny/new looking. hose it off really well with brake cleaner and make sure there's no sandpaper particles left and reinstall.

If it's warped or if there's a gouge in it or something uneven, this can usually take care of it pretty easily/quickly. just take your time and go slow.