Yamaha G1 Starts Up Great But Loses Power and Sputters Under Acceleration

Malibujoel

Member
Hi All.
I just picked up a Yamaha G1 golf cart that has been sitting for a few years. So I cleaned out gas tank and put in new fuel. New fuel filter and fresh oil and new battery and new cables. Also has a new spark plug in it. Starts right up and idles great. But when I accelerate it loses power and sputters under acceleration. I replaced the carburetor thinking it’s probably gummed up and plugged. Still same issue. Any suggestions would be much appreciated!
Thank you in advance.
 

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HotRodCarts

Cartaholic
Are you sure the golf cart is actually running or is it just cranking over on the starter? Dose it have spark and compression? Welcome to the forum. :hattip:
 

Malibujoel

Member
Starts right up and has great idle. I can start to accelerate just fine for a few seconds and then loss of power and sputters. But never dies or rough idle.
 

Malibujoel

Member
And yes the cart is running. I can drive it in reverse and forward except for it starts to loose power in both directions and sputters.
 

Malibujoel

Member
I just took a compression test. 90 lbs. I removed the muffler and looked at piston. No scoring. I assume just sitting the rings are stuck.
 

Malibujoel

Member
Thank you hotRodCarts!
I just removed the cylnder and on top of piston reads 25. So I assume .25 over. Bore still looks good. Can still see the cross hatch marks. Think I will go with a new piston kit with rings .25 and new gaskets instead of just rings to play it safe. Any thoughts before ordering parts?
 

HotRodCarts

Cartaholic
If the piston is stamped .025 over. If the skirts on the piston aren't scored you could probably still use it. I'd have the cylinder honed.
 

Malibujoel

Member
Thanks. The difference in price with a new piston or not is around $20.00. I opted to get a new piston. Old piston a bit rough on the top. Going to slap in a new coil for good measures. I hope for success after replacing all the parts.
 

WallysWorld

Member
I had a similar problem and narrowed it down to my throttle cable having breaks in the outer covering allowing too much play. I have ordered 2 now, both wrong, but labeled as G1 cables.. so for now I have heat shrink'd the broken areas and on one pieces really rigged it with a few pieces of metal clothes hanger and some zip-ties to give a little strength. seems to working good now without the issue you are describing... so I guess what I am saying in my long winded reply is, check your throttle cable.. hahahaha
 

Malibujoel

Member
Thanks Wally’s World! I will take a look at the cable over the weekend and see if it has any issues as you described.
 

Malibujoel

Member
I installed the new piston and rings and gaskets for cylinder head. Also installed a new ignition coil for good measures. Went to fire it up and a no go. Fuel was coming out of exhaust port between muffler and head. Checked and had no spark. Checked and had battery voltage to coil. But the ground wire going to coil was not supplying ground. So I used a jumper wire from a good ground to the ground side of coil and she fired right up and seems to run ok. I checked oil from oil pump and barely any oil comes out but might be normal but not sure how much it should supply to carburetor.
Few questions. Does anyone know where the ground from coil goes to and exactly we’re? Also how much should the oil pump squirt to carburetor? Muffler is just held on with 2 springs and that’s it? No support at body of muffler? Just moves around quite a bit.
Any and all inputs are greatly appreciated!
 

Malibujoel

Member
Seems like allot of throttle travel before trans engages. What is the measurement to be at throttle cable before engagement of trans?
 

Malibujoel

Member
A few other items that are a issue. Cart does not idle on its on unless you lightly throttle accelerator pedal. Has new carb and tried to age adjustments on carb. Also with a light throttle still has a slight popping from exhaust?
 

Malibujoel

Member
I just went back out and unplugged and plugged back in all connectors at the CDI thinking possible corrosion or just a bad connection at one of the 6 wires. Fired it up and now idles just fine????
But won’t stay running without my make shift ground to ignition coil. Brought multi meter back out to find ground good in wire up to connector that screw goes through coil holding onto engine cover . Cut open heat shrink around connector to find wire broke off. Put new connector on and low and behold it runs.

Only question left are there supposed to be brackets or straps that go around muffler to secure it or the muffler just floats on springs holding on to baffle that bolts the exhaust port of cylinder head?
 
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