Rebuild engine or not?

[steelhorse79]

I just picked up an older marathon that did not run. I planned on totally rebuilding the motor, but thought I would see if I could get it running first. Compression is 85psi. It has strong spark , but no fuel. They told me the engine was filling with gas and a mechanic told them it needed seals(I assume crank seals). I found the fuel pump was hooked up wrong and fuel was going directly into the crank case. I turned it over and fuel blows out the vacume hose. how can I clean this out before I try to start it?Could damage have already occured. I believe its an 89 cart with a ec25-3pg engine. How does 85psi sound for compression? Thanks in advance for any opinions. Also I have a workshop manual on the way im just anxious to get some thoughts.

[Plumbergs]

85psi is pretty low. Sounds like its time for a rebuild.

[steelhorse79]

What is the psi of a healthy engine?

[ScooterMcTavish]

Around 130. Generally anything under 100 is due for a rebuild.

[Dave Box]

85 psi is terminal so it is time for a rebuild. It is not a difficult job but you will need some mechanical aptitude. I enjoy this stuff and my finger itch to rebuild another, conversely if you don't enjoy it then this might cloud your decision. If money is no object (and that applies to only a few) I would pick up the complete kit at ~ $400 ish. If you are on a budget then you already know that you need the top end kit ~$200. Before you decide try this. Grab hold of the clutch on the engine and look at the shaft it is attached to. Now pull the clutch up as if you are trying to lift the engine. If there is even the slightest movement between the crankshaft and the engine you have more problems than just compression.
Whatever you decide I urge you most strongly to replace the crankshaft seals. It is all a pain but when they wear they gradually slow your engine down until one day it just won't run.

Dave

[steelhorse79]

I have no problem with rebuilding ,have done many 2 stroke dirt bikes in my day. I actually checked the crank just like you posted when I bought it. I do not feel any movement at all. I only paid $100 and figured to put about 4 or 500 into it. The rest of the cart is in very good condition. 1 more question is what is the best way to block off or eliminate the oil injection. We always did this on our dirt bikes or 4 wheelers so the first thing I want to do is take this one off. Great site,it is always great to hear from people who have been there done that.

[Dave Box]

I don't know if it is the best way but the easiest way (and thus in my opinion the best way) is to cut the oil pipe about an inch from the elbow behind the carburetor and drive an appropriately sized screw covered in mastic into the pipe. Then you can simply undo the two bolts that hold the pump to the fan cover and junk it. I also junked the oil reservoir just to keep it tidy under the seat. Premixing should be done at 128:1 which is actually 1 ounce oil to 1 gallon of gas. The only exception is after a rebuild when EZGO recommend 40:1 for the first tank.

Dave

[steelhorse79]

Thanks Dave for the great info. Do you have any oil you prefer? I always ran golden spectro in my bikes but have read on here people like klotz and some dont care, what do you think?

[bbriggs]

I wonder how much one can depend on compression readings of a 2-stroke engine with obvious fuel delivery problems? If the rings are not properly oiled can one rely on such a reading?

[steelhorse79]

got cart running last night ,will take compression test again to see if i get something different.