EZ Go Robin 2 Cyl 96?? Bogs down...

[Truckntran]

Hi guys....I need to have this cart up and running well asap for an upcoming wedding and it is driving me nuts. It is a TXT around 2006? model cart that has a '96 or so Robin 2 cylinder 4 stroke installed. (Cart shop did the swap when the old cart rusted out but didn't swap over the old data plate.)

After working on it for 2 days, it is finally back to where it was when it died 2 weeks ago.

Symptom: Full gas pedal results in poor acceleration but if you are gentle with the accelerator the engine will reach max governed speed eventually. Low power up hills. Feels like the second cylinder kicks in and runs great occasionally.

What I've done: Initially for no spark condition:

Cleaned and tightened all wiring connections. New coil last year, so installed a new ignitor and voltage regulator and solenoid while I was at it - the old parts were rusted and I did not trust the grounds.

Removed and cleaned off mounting bracket for electronics, and reinstalled on clean bare metal with new hardware and star washers.

Still no spark. (Been testing spark with new and old plugs. no difference)

Did HEI conversion - Now it runs and fairly well too. Nice fat blue spark. I suspect a bad ignitor. (Pulser coil is out of spec but functional still)

Seafoam treatment, cleaned visible carb interior with gumout spray. Air filter is ok, wires look good, lots of new grounds, etc.

Adjusted valves to .004 stone cold. At .006 it ran worse.

Sitting in the shop in neutral it will run up to max governed speed if pedal is pressed down slowly.

Immediate full pedal results in it momentarily bogging, then it accelerates as it clears out .

I have not done any carb adjustment or cleaning other than what was mentioned. Spraying carb cleaner over possible leak areas has no effect.


Any thoughts? What's next?

[trig123]

Compression is ??

[CP241]

Originally Posted by trig123

Compression is ??

What he said. Check compression. And make sure the choke is off and the throttle is wide open for a true reading. Not holding the throttle open will drop the numbers way down.

My TXT was running very similar to what you describe. Very poorly... I checked compression. 1 cylinder was around 70psi and the other was around 100psi. very low...

Luckily for me the valves were WAY tight giving the lowered compression readings. After adjusting to .004 i'm up to ~150psi on both cylinders and it runs great. I don't know what the actual compression spec *should* be, but it's a completely different animal now.

[Truckntran]

Just checked hot compression about an hour ago....150 psi with the first pulse around 95. It seems quite healthy compression wise to me.


I also got out my spark tester--it's one of those you put in the spark plug wire between the plug and the wire. Both cylinders have spark, but when I pull the plug wire on one cylinder it seems to not affect it very much when it is running poorly. It's almost like the coil doesn't have enough zap to make a good spark at both plugs. If I could find a 2 wire coil pack at NAPA or Advance, that's the next thing I'd try. I hate just tossing more and more parts at it.

Perhaps the spark isn't as good as I had thought either, now that I am looking in daylight. (When I finally had spark after the HEI it was pretty dark in the shop. )



Am I correct in assuming that the HEI unit will either work or not work, and the quality of the signal changes little as far as it is concerned? I have yet to even look at the Pulsar or its gap....been avoiding that task..

[Truckntran]

New info.....

With the flywheel side plug hooked up, and the other wire hooked to a grounded spark plug resting against metal, it runs about the same as it has. IE one cylinder.

If I hook the wire from the other cylinder to the near cylinder, it barely runs or won't run. I'm guessing that there is a coil issue now.

Not much if any difference whether the plug wire is on or off the clutch side cylinder. It does have compression and correctly adjusted valves.

Is there any automotive coil I could use with the two outputs? Or could I mount two coils and run the same primary leads to both?

[Truckntran]

Update: I was able to use a GM coil pack with two outputs and two new plug wires to match the coil. It started right up, and took a while to clear out. Now it accelerates pretty well and the second cylinder no longer cuts out. It does have an occasional rough spot or backfire, probably I will be redoing the head this winter. But now it runs well enough to use. I can stop on a hill and get going pretty well as power seems pretty good.

Moral of the story: never assume something is good just because it is fairly new. Shoulda gotten a coil right off.. I am betting the bad coil is what killed the ignitor, and possibly the second ignitor never had a chance....

[trig123]

I use the OEM coils. Works better .

[Truckntran]

Originally Posted by trig123

I use the OEM coils. Works better .

OEM coil was a few days away so....Time to make do with locally sourced parts.

[CP241]

Good find. I did the same thing on my Yamaha. After about 4 aftermarket ignitors, I gave up and used a Chrysler ignition module and ballast resistor, and it ran great. $30 Chrysler parts vs. a $400 ignitor, no contest. It still runs great to this day with no issues at all :)

[CPS]

Also, I know you said you had not opened up the carburetor, but the number one reason these carts bog down, especially upon take off, is a partially clogged carburetor main jet. The other two main reasons for engine bog down is: valves need to be adjusted to .004, and the overlooked reason, bad gas or gas that has been sitting in the tank for over 30 days! If you are using untreated pump gas in your cart, the ethanol in the pump gas absorbs the moisture out of the air, then this moisture settles in the bottom of the tank and carburetor bowl causing no start or hard to start symptoms. It only takes 30 days for this to happen on untreated pump gas!
It’s way easier to do this by completely removing the carburetor.

1) remove air box
2) disconnect fuel lines, choke cable, throttle cable
3) remove 2 nuts holding on the carburetor, carefully slide carburetor off its studs to retain gaskets. TIP: If the carburetor hits the starter/generator while removing carb, just tilt carburetor downwards at the end of the studs, then push downward slightly, this will give you just enough room to remove the carburetor
4) drain gas out of carb by removing bottom bowl retaining bolt
5) carefully remove bowl not to damage bowl gasket. If the bowl is stuck, lightly tap on the bowl itself up as close the carburetor body as you can in a circle motion with the handle part of something like a 3/8 ratchet or similar
6) remove the brass main jet with a flat blade screwdriver (its up inside the threaded hole the bowl bolt goes into)
7) use a very small wire or torch tip cleaning kit to clean out the jet. Spray everything down with carburetor cleaner and reinstall in reverse order.

The jet is brass, so you don’t need to tighten it down HE-MAN tight, just snug tight. IT WILL STRIP OUT IF YOU GO TOO TIGHT

Hope this helps, if you haven’t fixed your issue so far.