1983 EZGO Gas Fouls Spark Plugs Insanely Fast

belercous

New Member
A friend of mine has an early 1983 EZGO golf cart with a 2 stroke engine which gas fouls spark plugs insanely fast. Lately the plugs don't last 15 minutes. Very weak power, often after-fires through the exhaust. Plug gas fouls quickly, looks sooty. The problem has steadily gotten worse over time.

Top end is new; compression is 120.
Coil is good, replaced with another used one, no change.
Replaced the ignitor.
The spark is bright blue (even with plugs that won't start the engine. Yeah, wtf? Tried opening up the gap to get a bigger spark, no change. We're gonna try a hotter plug, but that only matters when an engine is running hot, it doesn't give a hotter spark.
Reed valve works (no blow-back into air filter), not that it would make it run rich.
The fuel pump lower (engine side) diaphragm, is good; no cracks or leaks where fuel could get by.
The carb seems good (floats not sunk, throttle butterfly rod is tight, needle valve & seat are fine, all internal jets open, the 3 idle holes by the butterfly valve are open). A new carb made no difference.
There is no evidence of the crankshaft seals leaking, nor is there any indication of any other leak in the crankcase.

Does anyone have an idea about what is going on? I've spent many hours trying to fix this problem, yet it just keeps getting worse. I've always been a fairly decent mechanic & am quite familiar with 2 stroke engines on dirt bikes, boat engines, weed whips, etc., but this issue has me at my wit's end. Any help would be most appreciated.
 

Rstaley

Cartaholic
The two things that I would look closely at would be the muffler and the mixture. These carts had a history of clogging up their mufflers after time. You could find volumes of information about this, but most people just take the muffler off and have a “muffler BBQ” to cook out the build-up of blockage. You can just loosen the muffler (I know thats easy for me to say) and create an exhaust leak to see if it relieves anything enough to make a difference. The other thing is the mixture. All of the documentation that I have found specifies a mixture of 128 to 1 (and ounce of oil to a gallon of gas). That sure sounds too lean to me, so I have always used 90 to 1 as my standard, but I hear a lot of guys say that they use 50 to 1 (these are usually people who are more familiar with chain saws and motorcycles). It is worth looking at. Other than that, I just hate it when everything is perfect and the thing still doesn’t work right (I’ve had my share of them,).
 

belercous

New Member
The exhaust is clear. I really thought I had it solved when I thought of it, but no, it flows very freely. 128:1 is an insanely low amount of oil, but that's what he runs as premix. On dirt bikes, weed whips, etc., as a rule I used 32:1. My boat runs 55:1 & I never fouled plugs on any of them. This is gas fouling. I've been through two carbs (taken apart, everything checked) no change. It makes no sense. The choke does not ride on.
 

Zman

Cartaholic
Are you using the fuel pump made for the cart or some type of electric pump? some electric pumps have too much pressure and can case flooding at wide open driving
 

Rstaley

Cartaholic
Zman has a good point there. The original system only supplies about 1.5 psi at most. Anything above that will get by the needle and seat. The carburetor wasn’t designed hold back a lot of pressure. I’d put a transparent fuel filter in the line to the carburetor and watch to see what is going on. It should never be full of fuel, but just have enough in it to supply the need of the carburetor as the float opens and closes the needle and seat. You will see some fuel come into the filter when the needle and seat is open, but when it closes off, the filter will stop filling, (unless there is a leak in the system) until the next shot is needed. Many people think they should see the filter full all of the time, and that just isn’t the way it works.
 

belercous

New Member
It has the original carb on it. It has a clear filter which rides about 4/5 full. Turning the carb upside down I can't blow air into it. A human can blow about 3-3.5 psi.
 

belercous

New Member
I read about an HEI coil fixing another older EZGO like my buddy's. Perhaps a hotter spark would fix his too. If not, I'll return it. (I know that parts sellers say they don't accept returns on electrical parts, but they don't have any choice if it's bought on a credit card) Where can I find one of these? Buggies Unlimited doesn't sell them.
 

HotRodCarts

Cartaholic
If the spark is continous and bright blue I doubt that's the problem. You can buy the HEI coil and module from most auto parts stores. Here's a link to a thread where another member just did the HEI conversion. There's also several other threads here with details on doing the HEI conversion.
 
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