Puzzled puzzled puzzled

[ezgogonebad]

Just overhauled 87 ezgo marathon problem is interment istarts here's what I've come up with cleaned carb 3 times sprayed crank seals with starting fluid no change won't try to hit got good spark. Drain gas from carb spray starting fluid in carb and she starts. Put a little gas in carb and she starts and runs I don't know compression but when you put hand over carb it will suck your hand into it hard so I believe crank seals are tight. Cart would run and run awesome but you would have to jack it up spray starting fluid in it and once It started you could drive it all day till you shut it off then it wouldn't start back till you did the same thing again starting fluid till it hit then she would start. I think it's the carb but I've cleaned it 3 times so I'm about to give up I hate to spend money on a carb I don need but I don't know what else it could be.

[1989Marathon]

Does your carb have and idle-air screw? If it does, try opening it to about 1.5 turns from fully closed.

[ezgogonebad]

I have checked that and have adjusted it while trying to start cart and no change

[1989Marathon]

What does it do if you choke it?

[ezgogonebad]

Motor changes noises and starts a funny ticking noise like if it had valves and then most of the time back fires so loud it will deafen you

[1989Marathon]

I would focus on the pilot(low speed) circuit in the carb. It is likely plugged. I know you said you cleaned the carb 3 times, but "cleaned" is a relative term. When you spray cleaner into a hole in the carb, it has to come out somewhere else. If not, it isn't clean. I'm not familiar with that carb, but I would remove the bowl and the air screw, spray cleaner into the air screw hole, and make sure it comes out in the bowl and somewhere near(likely ahead of) the throttle butterfly.

[redcloud]

Do a compression check. If you have low compression it will hard start if you are under 90#s. If above 90#s up to 120#s , check your throttle plate to make sure it closes tight when you let off on pedal completely. the throttle plate should only start to open when you have had about 1/2" pedal travel and hear the click of the limit switch. This causes back firing also if the throttle plate does not close allowing fuel to be sucked in after you have dropped off the limit switch, so when you hit the pedal the next time, it will ignite the fuel left in the exhaust.
One other thought, check your head bolts to make sure you do not have a loose head or blown gasket if low compression is detected.

[Dave Box]

Here is another $0.02 but with the caveat that it is always a long shot to diagnose long distance.

First I am with Redcloud inasmuch as correct compression is far more important in a two cycle than a four cycle. You do need to beg, borrow or steal a tester and get a number. If you are below 90 psi then whatever you spend on a new carburetor will not be helping.

Secondly you cannot test the front crankshaft seal, there is just too much stuff in the way. That said if you really got onto the rear seal and it made no difference then the front maybe good as the rear one takes more stress than the front.

Now for the hypothesis (which is not quite a wild guess as this happened to me on my 86). If the fuel pump diaphragm is damaged it can leak fuel down the pressure pipe and into the crankcase, this causes an unusually rich mixture which will literally flood the engine. When you drain the carburetor and use some easy start (and btw go easy with that stuff) you reduce the fuel supply and introduce a highly volatile mixture which gets the engine running. Once running the pump will start pumping and stop leaking, until the engine stops. When you pull the choke with the engine running you increase the fuel ratio on what is probably a very rich mixture. The unburnt fuel collect in the exhaust manifold until it is ignited with a backfire that will blow your hat off, damage your exhaust baffles and pressurize the crankcase possibly blowing out a seal.

Removing the disassembling the pump is relatively easy and if you do find a crack in the diaphragm I guarantee you have your solution but you will need to look hard as the crack will be easier to feel with your finger tip than to see.

Good luck

Dave

[redcloud]

Agree with DB as that is also a very good point to look at.

[ezgogonebad]

I ordered new carb and fuel pump yesterday hopefully this will fix it. Let me ask this If you had bad compression wouldn't the cart lack a lot of power this thing will haul me and my dad really fast and fly up some pretty steep hills me and him are about 500lbs together plus the carts got 22" tires