85 Marathon Setting for 3 Yrs / Clutch Issue

[TX Buggie]

Noticed what seems to be a lack of power coming out of this thing. Real slow coming out of the gate and takes a while to come up to speed. Any ideas where to start? Carb Adjustment maybe?

[Mr Marathon1990]

ha ha ha, try a bigger motor, mine is waiting a complete rebuild kit, soon it will be back on the mesa

[ruredy]

might be having driven clutch issues. Does it run better in reverse than forward?

[TX Buggie]

Originally Posted by ruredy

Does it run better in reverse than forward?

It does seem to take off better in reverse than forward.

Originally Posted by Mr Marathon1990

ha ha ha, try a bigger motor, mine is waiting a complete rebuild kit, soon it will be back on the mesa

Ok, if I see that thing on the Mesa, and if it got there under it's own power (no trailers or pulling it), the beer is on me!

This fuel starvation problem is kicking my butt. The fuel systems on these thing are so simple, but.......

Here is my problem, I'll prime the fuel system, fill line and filter going to the fuel pump by applying air pressure to tank, then disconnect the line going into the carb and run engine filling line from pump to carb, good steady flow of fuel, looks like she's pumping fine. Everything full as far as I can see, run the thing around the block a time or two, then she act like she runs out of gas, at this point, fuel filters are bone dry, like I am sucking in air not fuel. Replaced all the lines, and bypassed the dropdown tube going into tank with a hose directly into the fuel tank to first filter, all clamps good and tight. Replaced fuel pump, same problem.

I think my problem is either a bad seal where pump mounts to engine causing a leak and low vacuum / pressure so my pump can't lift the fuel up out of the tank, or worn crank case seals causing the same thing. I don't think the little gaskets are available for the fuel pump, where it mounts to the engine, so I will make one and see what happens, if this doesn't work, I'll either go with a electric fuel pump or replace the crank seals. Any thougts?

[ruredy]

If your crank seals are bad a electric fuel pump won't help much if any.
You also kinda need to do a compression test (both forward and reverse.)

[TX Buggie]

Ok, so I did the compression check last night. Did a few in both forward and reverse, engine at temp, for verification purposes.

Forward: Averaged 105 lbs
Reverse: Averaged 117 lbs

I know these numbers could be better, but not to bad. Still trying to wrap my mind around why the numbers are different between forward and reverse. No valves, what gives?

So again, my problem seems to be that the fuel pump can't pull fuel out of the fuel tank. If the filter prior to the pump is full, I have a steady stream of gas exiting the fuel pump. So I cruise it, and after about 10 min or so, fuel starvation, filters are bone dry. Would the compression numbers above cause a weak fuel pump. NOTE: pump is new and had same issue with previous pump.

Second issue, it massive vibration at top speed, still looking into this.

[ruredy]

Originally Posted by TX Buggie

Ok, so I did the compression check last night. Did a few in both forward and reverse, engine at temp, for verification purposes.

Forward: Averaged 105 lbs
Reverse: Averaged 117 lbs

I know these numbers could be better, but not to bad. Still trying to wrap my mind around why the numbers are different between forward and reverse. No valves, what gives?

rotation of the crank pushes rod/piston to whichever side off the cylinder wall it's rotating towards. rings seal different depening on direction of rotation, the psi numbers are always lower going forward cause that's the direction it runs the most an have had more wear.
Compression shouldn'd be really related to fuel pump operation. did you check the gas cap vent? the only other thing I can think of right off is maybe a vac leak at the base of the cylinder or maybe the seals that gets worst the hotter the engine gets.

[TX Buggie]

Originally Posted by ruredy

rotation of the crank pushes rod/piston to whichever side off the cylinder wall it's rotating towards. rings seal different depening on direction of rotation, the psi numbers are always lower going forward cause that's the direction it runs the most an have had more wear.
Compression shouldn'd be really related to fuel pump operation. did you check the gas cap vent? the only other thing I can think of right off is maybe a vac leak at the base of the cylinder or maybe the seals that gets worst the hotter the engine gets.

That makes sense on the different compression readings.

Gas cap vent works, I even removed the cap for verification, and problem still exist. When you say "leak at the base of the cylinder or maybe the seals that gets worst the hotter the engine gets." I am thinking you are referring to the seal between the cylinder and the case and or the crank seals, is this right?

Man this thing is kicking my butt!

I might try an external fuel tank with some gravity feed for a while just for giggles.

[bfi93]

I am going through the exact same thing with my 1987 ez go. We have almost narrowed my problem down to crank seals but not 100% sure on that just yet. My compression is about the same as yours and I am haveing the fuel starvation problems exactly as you described. Will your cart run better with the choke on by chance?

[divot61]

for your shuttering problem it might be the driven clutch, put it up on the jacks and hit the pedal, watch the clutch on the rear end "running true or not?" sometimes the splines inside the driven clutch wear out, i have also seen the output shaft on the rearend get wore