oily muffler

hecktwa

I have recently purchased a 1989 EZGO cart and I'm doing a top end job on it due to low compression. When removing the muffler assy, I noticed it seems to be caked with oily deposits up inside of it. After installing a new jug and piston assy, I kinda hate putting that oily thing back on there. Now since I won't have all that blow-by anymore in the cylinder...will it sort of "clean" itself over time with a tighter fit and new restored compression? I see where marathon mufflers are very pricey and the muffler itself is otherwise in good shape, I would like to avoid the cost of buying a new one. Any thoughts? Thx

BGW

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cart around

Throw the muffler into a hot fire for a few hours. Lots of threads about muffler barbecues on here.

While it's apart, change your crankshaft seals. It's worth the effort.

hecktwa

I had not thought of that, and sounds like great idea! Good timing on that too as I currently have large burn pile on my south 40 that I will be firing up in the next few days, Ill throw the muffler on it and let it bake!

Yeah, I've changed the crank seals out already...good idea there as well. I'm really looking forward to getting everything back together and seeing how it's going to run. It actually didn't run half bad before even with only about 90lbs compression, so I'm looking for some definite improvement when I get done, thanks for the suggestions.

hecktwa

Well, after an extended period what with waiting for clutch pullers and various parts on my repair job, I finally got everything back together. I have a problem even though I took my time and took great pains to get everything right, I've done something wrong...I have very low compression. About 70 lbs in both fwd and rev and at any throttle position. The repairs I made were new cylinder, piston, rings, all related gaskets, new carburetor, replaced both crank seals, new starter and belt and new battery. I premix fuel and started with the first tank at a slightly richer mix of 100:1 for break-in purposes. I removed the oil reservoir tank and related hoses and linkage off the front cover. I plugged the lines that previously went to the carb. I also bbq'd my muffler while I had everything out. I have pulled the cylinder and piston back off to see if perhaps I had installed the piston or rings incorrectly(I hadn't). The port opening on the piston was facing the intake side and the beveled side of both piston rings were installed facing up. I did notice quite a bit of fuel run out of the exhaust port and had run down into the L shaped pipe between the head and the muffler. Likewise, when I removed the reed valve assy, it too was quite saturated in fuel. What seemed odd to me is that with the cylinder off and looking down in the crankcase area, it seemed completely dry. Perhaps that is normal for a 2 cycle, I'm no expert on them for sure. When I try to start the cart it only moves by the spinning of engine via the starter drive belt...it's not firing up on its own like it used to do after a few seconds of cranking starter. Before tearing it back down, I tried the trick of spraying carb cleaner down around the crank seals while cranking it with wheels raised off the ground and it made no difference that I could tell. This has me completely stumped. I've done or checked everything I know to do. I started this project in an attempt to make the cart perform better as it had become a real oil burner and just 90 lbs compression...but at least it ran! Now I'm worse off than when I begun. I must have overlooked something or done something wrong, but right now I have no idea what it is. Any thoughts and advice greatly appreciated.

cart around

EZGO says 40:1 on the first tank of gas after a rebuild.

I would check for spark first.

After you exhaust all troubleshooting options, and decide to take it apart again, it might be time to measure the bore, and the piston. Also measure end gap on the rings. I'm wondering if somebody sent you an oversize jug with a standard size piston.

Was the new cylinder crosshatched good? I would think that it was already done at the factory.

One last thing. The fuel air mixture flows under the piston, through the crankcase, and up into the cylinder. That's how the bearings are lubricated. It should be wet down there.

hecktwa

I wasn't aware of the recommended 40:1 mix....I will drain the tank and re-do that before re-starting whenever that may be.

I did check the spark and had a good, steady blue spark with the plug out and grounded.

I can't remember who I got the top end kit from, ordered online, it was a few months ago but it appeared to have a nice cross-hatch finish in the bore. Also on assembly, it felt very snug as I slipped the cylinder down over the piston. However, I didn't break out the micrometers and take any measurements. I will do that now that I have the top end apart to check and see if it is oversize bore and that the piston size matches bore size with clearance within specs.

So I guess the key symptom I'm seeing is that above the piston in the exhaust port and pipe and also in the reed valve area, it is literally flooded with fuel while the bottom end is basically dry. When you say the fuel mix come up from the crankcase under the piston, would it be correct then that the fuel originates thru the ports on the side of the piston? Could possibly the reed valves be installed wrong?

cart around

Yes, the fuel enters through the intake port of the piston, and travels underneath.

I'm thinking that if the reed valves were an issue, fuel would be spitting out the intake into the air cleaner.

It seems like the lower port is blocked not letting the mixture flow through.

Did you wrap the ends of the rings around the alignment pins that are in the piston grooves?

Dabble Inn

Dang 70lbs isn't good, I just did mine and only getting 110lbs. My 32 year old one was getting 115lbs when I took it off ffs, I did check the piston and bore and they were within factory specs but I forgot to check the ring end gap.

Just an fyi;
To check ring end gap slide the ring down the cylinder about a 1/2" and square it up by inserting the piston down on top of it. Then use a feeler gauge in the gap.. Here's the specs if ya need them;

Cylinder Bore 2.8350" to 2.8357"

Piston 2.8321" to 2.8327"

Ring End Gap .008" to .016"

hecktwa

Well, I've checked a few more things. The ring end gap is right at the max spec of .016. Maybe the rings are cheap quality and haven't come close to seating yet? The new cylinder and piston set I ordered off ebay is standard size but the mike shows it actually slightly below minimum size for both piston and cylinder. The piston is 2.823 and the cylinder is 2.829. I haven't miked it at various places on the piston to check and make sure the diameter is consistent at every location and the same with the cylinder. I've heard the war stories about cheap third world parts and that could be the case here. After all the piston and cylinder do not mike out within the EZGO specs. It doesn't seem to be off much but what matters to me is the piston to wall clearance being correct and that it is consistent at all points of the piston and cylinder.

I do need to correct one thing I previously said about the bottom end being basically dry. Well, the cart had sit for a few days and I guess what fuel mix was on top had run to the bottom of the case as it had a fair amount of fuel standing in the bottom of the case that I could clearly see once I removed the piston. Would that be normal? I mean would there ever be a time when you would actually have fuel standing in the bottom of the case?

I always operate with the mindset that if you end up with a problem you didn't have to begin with, it usually is either something you did(or didn't do) incorrectly or you got a defective part...even a new part! What do you all think?

hecktwa

The cylinder and piston measurements are off a bit...it's tighter at the bottom than it is at the top of the piston. There is already a pretty good amount of scruffing on the lower skirting of the piston just from the spinning over of the engine while trying to start. I really don't understand the amount of fuel standing in the bottom of the crankcase. I have it down this far, I might as well yank the engine on out again and this time go ahead and open up the case and start at square one and try to figure just what is going on here.