88 EZGO won't rev up to top speed

[1lane66]

Ok I'm at wits end and cann't for the life of me figure this thing out. Worked on multi million dollar fighter jets for 25 years and this 2cycle has gotten me down for the count...Ouch! Here's what's going on,,Have spark, plenty of fuel to carb from fuel pump, good crank case pressure, over 120 psi, spark, clean and clear air filter and canister, exhaust clear and breathing good all the way through the muffler (BBQ'd it) fuel mix at 128 to 1, have gone over all bolts and nuts for tightness, have found no air/vaccume leaks at any gaskets or mounted engine parts, did top end rebuild. Cart will run at a walk but will not ramp up to top end speed even with it up on jack stands. While it's running it has a slight sputter or miss. Have changed out spark plug with no change, took carb completely apart ( 3 times ) following the diagram that has been posted several times down to where there was nothing left to take apart, used fine welding files to clean out all ports and passages, checked float level, tried putting fuel straight to cylinder with no change in engine speed, have replaced carb gaskets each time it was cleaned, has new plug wire and all other wiring is fine, most of it is new. What am I missing??? Been going in circles now for several weeks,,actually months, try to get it to run faster than a walk. Installed a new shorter belt a couple months back for the driven clutch. Driven clutch is free and appears it will work fine if I can ever get any speed out of it. Any Ideas out there. There is one other fellow carter that has the same problem as I do and we're just trying to get them up and going. Thanks Donald Sorry I was so long winded but was trying to cover all I've done to this point. Dave if your out there tell me what you think, could sure use your insight.

[sharse36]

Did you look to see if you got the piston in the right way? Also did you replace the crank shaft seals?

[1lane66]

Yes sir, did that, Dave ask me about that after I finished the top end job, piston is in correct and good seals, good crank case pressure as well as the 120 psi. For got to say this is on a 2pg 1988 model marathon ..

[racin161]

lane66 TWO things to think of and i'm gambling. First is have you conformed that the choke is in fact full open and inline with the carb at operation ? is the throttle opening to full throttle ? Remove the cables and air tube and maybe make a fixed linkage out of wire for the choke to keep it in place during operation and manually operate the throttle linkage! see what it does on jack stands. OK if the same thing the sputtering or lack of power may also still be in the ignition system.Possible coil breaking down or a faulty ignitor. as you have already changed the coil wire I think and new plug. I would seriously think about the hei conversion to eliminate these problems which will not be expensive and you will have a bullet proof ignition. Just my thoughts Dave may chime in but were grasping at straws also and trying to get this thing running. Please give us an update.

[Dave Box]

Donald, I agree with racin161, we are grasping at straws here but I agree with everything above. In addition here are a couple of other obscure points.

Brew City once had an strange problem. Cutting a long story short his regulator died and raised the output of the generator to 18 volts which overloaded the ignitor. Easy to check with a voltmeter across the battery.

Also I wonder what the rpm's are under load and with the back in the air. It might be worth investing in one of those little $10 tachometers on ebay.

Dave

[1lane66]

Thanks guys,, I had thought about the HEI conversion and looked through the treads for info and found a wiring diagram someone had posted on installing one ,,not sure if this one will work on mine. what all will I need and how to hook it up?? I think I've got a small tach some where in the shop that will work to check the rpm with. I have held the throttle all the way open with my hand while it was running just to make sure it was and the choke is all the way open while I was doing that. I'm more incline to go with the electrical side at this point for now and see where that leads to, HEI, another new cable and plug and what ever else I need to do the conversion with. Thanks again for the help,,,,Donald

[Ron Man]

I'm no expert on 2 strokes, but I agree with the cogincenti. Look at the ignition, and consider HEI conversion. I just did that on my 3PG and it solved my starting issue and made a huge difference in running / power. I can help you with pics and P/N's for the HEI conversion if you need it. (I'm also going to post a writeup w/pics on it to make it easier for others to do). Also, an easy check that someone told me about to verify crank seals are good: remove the fuel supply hose from the carb and crank the cart over with the plug out. If you get 1/2" or taller stream of fuel, then crank seals are good. Also, if you need a new carb, I have a brand new BV21 that I wound up not using.

[1lane66]

Ron Man,,thanks for the info. yes I would be in need of the parts and how you hooked yours up (HEI) and the carb how much incase I do need a new one? As for the seals I have plenty of crank case pressure cause I have removed the fuel pump and put my finger on the hole and can feel it each time it strokes downward or back toward the carb and without my finger over it while the engine is turning over it will almost blow fuel mixture to the top of the cart roof and with my finger just off the hole I feel a strong burst of pressure each time and there is no residue coming out around the seals. The pics and explanation of your HEI hook up would be a big help to all I think,,at least those of us that want to convert over. Thanks,,Donald

[Ron Man]

Donald:

Since you asked... here's my writeup. Let me know if you have any Q's.

http://www.buggiesgonewild.com/gas-e...tml#post657834

Now, if your cart is a 2PG, could you measure the length and diameter of your muffler for me? I've asked for them in a thread and nobody's responded yet. I want to see if a 2pg muffler can be retrofitted to my 3pg cart. I need a muffler bad, and a new 3pg muffler will cost more than my cart is worth!!! I can get the fab work done on the 2PG, but I need to know how far off the physical dimensions are first before I go buy one.

[1lane66]

Well finally,,,at last,,,IT RUNS!!!! Got the HEI parts today ,left work early so I could get them installed. Turned the key on , pressed the pedal and away it went . Runs like I thought it should. It was the ignition system that was breaking down and keeping it from ramping up to top speed. Still has a slight cut out at top speed under load but I think it's the float level is to low and not letting enough gas to the fuel bowl. I'm besides myself with joy. Thanks to all who help me with this. I was at the point of taking it to some shop and letting them fix it and charge me a bundle of money but thanks to you folks I got by with a bill of just $30. After all I did to this cart and turns out to be the ignition. I have really learned alot about this engine and cann't thank you guys enough for your help. Donald